JP2016061357A - Power transmission device and on-vehicle display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device which can surely prevent backlash between a rack and a pinion, and an on-vehicle display device which can surely prevent rattling of a display body in moving or in stopping.SOLUTION: A main rack 17 and a sub-rack 18 are carved on an extension wall 16 protruding from a back surface of a display body 3, a drive gear 10 of a backlash removal gear 12 is engaged with the main rack 17, and a brake gear 11 is engaged with the sub-rack 18. The backlash removal gear 12 includes: the drive gear 10 rotationally driven by the power of a motor 6; the brake gear 11 coaxially arranged with the drive gear 10; a friction plate 19 interposed between the drive gear 10 and the brake gear 11; and a coil spring 21 for elastically energizing into a direction for bringing the drive gear 10 and the brake gear 11 into press contact with the friction plate 19.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power transmission device having a backlash prevention means between a rack and a pinion that mesh with each other, and a vehicle-mounted display device that operates a display body using such a power transmission device.

  Conventionally, the display body is housed in a recess provided in a dashboard, etc., and this display body is rotated by a power transmission device equipped with a rack, a pinion, etc., so that the display body protrudes from the recess only during use. There is known a vehicle-mounted display device that can be used (for example, see Patent Document 1).

  A vehicle-mounted display device disclosed in Patent Document 1 includes a lid body that is pivotally supported by a dashboard so as to cover a recess, a power transmission device that rotates the lid body about an axis, and a dashboard. A sliding member having a guide hole disposed inside the display body, and one end of the display body is pivotally supported on the inner wall surface of the lid, and the other end of the display body is a guide for the sliding member. Inserted in the hole. The power transmission device includes a driven gear (rack) provided in the vicinity of the support shaft of the lid, a drive gear (pinion) that meshes with the driven gear, and a motor that rotates the drive gear. Installed inside the dashboard.

  In the vehicle-mounted display device schematically configured as described above, when the motor is rotated in either the forward or reverse direction, the rotation is transmitted to the lid body through the meshing portion of the drive gear and the driven gear. Rotates around the support shaft in a direction to open the recess, and the display body is pulled up from the recess and exposed on the dashboard. Further, when the motor is rotated in the other direction with the display body exposed in this manner, the lid body rotates in a direction to close the recess around the support shaft, and the display body is pushed down accordingly, and the inside of the recess is It is stored in.

  By the way, in the case of driving a movable body (lid body or display body) using a power transmission device having a rack (driven gear) and a pinion (drive gear) as described above, backlash between the rack and the pinion is prevented. Unless measures are taken, there is a problem that the movable body is loose during movement or is stopped. As such backlash prevention means, a backlash removal gear called a scissor gear is incorporated in the transmission path of the power transmission device, and two identical and coaxial gears constituting the scissor gear are engaged with the rack, and springs are engaged with these gears. In order to eliminate play by applying torque, a widely used one is used (see, for example, Patent Document 2).

JP-A-8-9291 JP-A-6-94103

  However, when backlash between the rack and pinion of the power transmission device is prevented by the scissor gear, it is difficult to incorporate a spring with a large load between the two gears constituting the scissor gear. The lash removal force becomes a small value, and it becomes impossible to reliably prevent the play of the movable body having a large total weight like the display main body. In addition, in an in-vehicle display device that rotates a display body using a motor as a driving source, it is common to transmit the rotation of the motor to the final stage pinion via a reduction gear train. There is also a problem that the number of parts and cost increase accordingly.

  The present invention has been made in view of such a state of the art, and a first object thereof is to provide a power transmission device that can reliably prevent backlash between a rack and a pinion. The second object is to provide an in-vehicle display device that can reliably prevent backlash of the display body during movement or stoppage.

  In order to achieve the first object, a power transmission device of the present invention includes a movable body that is movably supported by a support member, a main rack and a sub rack that are provided on the movable body and face each other in parallel. A drive gear that is pivotally supported by the support member and rotates with a motor as a drive source; a brake gear that is arranged coaxially with the drive gear; and a friction plate that is interposed between the drive gear and the brake gear; An elastic body that elastically urges the drive gear and the braking gear in a direction in which the brake gear is pressed against the friction plate, and the drive gear is engaged with the main rack and the brake gear is engaged with the sub rack. Made the configuration.

  In the power transmission device configured as described above, when the driving gear meshing with the main rack is rotated in one direction by the power of the motor, the braking gear meshing with the sub rack is rotated in the opposite direction to the driving gear. Since a large friction torque due to the urging force of the elastic body acts between the drive gear and the brake gear, the brake gear rotates in the opposite direction while always sliding with respect to the drive gear. At that time, since the elastic body presses against the friction plate between the drive gear and the brake gear to obtain a friction torque, a large friction torque is generated even with a small drive gear and a brake gear. Therefore, it is possible to reliably prevent both the backlash between the main rack and the drive gear and the backlash between the sub rack and the braking gear.

  In the above power transmission device, when a reduction gear train composed of a plurality of gears including a drive gear is interposed between the motor and the main rack, and the final gear of this reduction gear train is a drive gear, the final gear If the drive gear includes the backlash prevention means as described above, a standard gear without a backlash prevention function can be used for the remaining gears.

  In the power transmission device described above, the movable body may be slidably supported by the support member, but the movable body is rotatably supported by the support member and the main rack and the sub rack are movable. It is preferable to extend in a circular arc shape around the rotation axis of the body because the movable body including the display main body can be smoothly rotated.

  In this case, a pair of extending walls facing each other with a predetermined interval are provided on the back surface of the movable body, and a main rack and a sub rack are formed on the opposing inner surfaces of these extending walls, respectively. It is preferable that the movable body can be rotated with a good balance.

  In this case, a gear box that houses the reduction gear train is disposed between the pair of extending walls, and the drive gear is fixed to both ends of the support shaft that is supported by the gear box. The components of the power transmission device from the motor to both drive gears can be compactly arranged in a limited installation space on the back of the movable body, which is preferable.

  In order to achieve the second object, an in-vehicle display device according to the present invention includes an in-vehicle display body having a display screen and a power transmission device for moving the display body between two different positions. In the display device, the power transmission device includes a drive gear that rotates using a motor as a drive source, a brake gear that is arranged coaxially with the drive gear, and a friction that is interposed between the drive gear and the brake gear. A plate, an elastic body that elastically biases the drive gear and the braking gear in a direction to press-contact the friction gear, and a main rack and a sub rack that extend in parallel to the display body, The drive gear is engaged with the main rack, and the brake gear is engaged with the sub rack.

  In the in-vehicle display device configured as described above, a main rack and a sub rack that extend in parallel with each other are provided on the display body, and a drive gear that meshes with the main rack is rotated in one direction by the power of the motor. Then, the braking gear meshing with the sub-rack rotates in the opposite direction to the driving gear. However, since the friction torque due to the urging force of the elastic body acts between the driving gear and the braking gear, the braking gear is the driving gear. Will always rotate in the opposite direction while sliding. At that time, the driving force and the braking gear are pressed against the friction plate interposed between them by the urging force of the elastic body so as to obtain a friction torque. Even if the driving gear and the braking gear are small, a large friction torque is obtained. Since it can be generated, not only the backlash between the main rack and the drive gear but also the backlash between the sub rack and the braking gear is prevented, and it is possible to reliably prevent the display body from being loose during movement or stopping. Can do.

  In the above-described in-vehicle display device, a pair of extending walls facing each other with a predetermined interval are provided on the back surface of the display main body, and a main rack and a sub rack are formed on the facing inner surfaces of these extending walls, respectively. It is preferable that the display body can be moved smoothly with good balance.

  In the power transmission device of the present invention, the movable body is provided with a main rack and a sub rack facing each other in parallel, and when the drive gear meshing with the main rack is rotated in one direction by the power of the motor, it meshes with the sub rack. Although the braking gear rotates in the opposite direction to the drive gear, friction torque due to the urging force of the elastic body always acts between the drive gear and the brake gear. Not only the rush but also the backlash between the sub rack and the braking gear can be surely prevented.

  In the in-vehicle display device of the present invention, the display main body is provided with a main rack and a sub rack extending opposite to each other in parallel, and when the drive gear meshing with the main rack is rotated in one direction by the power of the motor, the sub rack The brake gear meshing with the drive gear rotates in the opposite direction to the drive gear, but friction torque due to the urging force of the elastic body always acts between the drive gear and the brake gear. Both backlash between the secondary rack and the braking gear are prevented as well as backlash between the two, and it is possible to reliably prevent backlash of the display body during movement or stopping.

It is the perspective view which looked at the vehicle-mounted display apparatus which concerns on the example of an embodiment from the front side. It is the perspective view which looked at this in-vehicle display device from the back side. It is a side view of this vehicle-mounted display apparatus. It is a rear view of this vehicle-mounted display apparatus. It is sectional drawing which follows the VV line of FIG. It is a principal part top view of the power transmission device with which this vehicle-mounted display apparatus is equipped. FIG. 7 is a perspective view corresponding to FIG. 6. It is sectional drawing which follows the VIII-VIII line of FIG. It is a disassembled perspective view of the backlash removal gear with which this power transmission device is equipped. It is a perspective view which shows the meshing state of this backlash removal gear and a rack. It is operation | movement explanatory drawing of this backlash removal gear.

  DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 7, an in-vehicle display device according to the present embodiment is a base material (not shown) such as a dashboard in a vehicle interior. ), A support body 1 fixed in the recess, a display body 3 rotatably supported by the support member 1 via a shaft 2, and power for rotating the display body 3 between a standing posture and a lying posture. A transmission device 4 and the like are provided.

  A gear box 5 is integrally provided on the support member 1, and a motor 6 is attached to the bottom surface of the gear box 5. A plurality of gears constituting a reduction gear train 7 are pivotally supported on the gear box 5, and a worm 8 fixed to the rotating shaft of the motor 6 is engaged with a first gear 7 a of the reduction gear train 7. A drive gear 10 that is the final stage gear of the reduction gear train 7 is fixed to both ends of the support shaft 9 that is supported by the gear box 5, and is arranged coaxially with the drive gear 10 as will be described later. The backlash removal gear 12 is constituted by the braking gear 11 and the like.

  The display main body 3 includes a movable case 13 having a rectangular opening 13a on the front surface and a display device 14 including an LCD or the like housed in the movable case 13, and the display screen 14a of the display device 14 is movable. The case 13 is exposed from the opening 13a. The display device 14 is a touch panel type display device in which a touch pad (coordinate input device) is stacked on the front surface, and can perform menu selection on the display screen 14a by pressing the user's fingertip or the like against the touch pad. It has become. Since the display device 14 includes a heat generating element that generates heat, such as a driver LSI or a backlight, the movable case 13 includes a heat generating portion 15 as shown by a two-dot chain line in FIG. Yes.

  The movable case 13 is made of a metal material having good thermal conductivity, such as aluminum or magnesium alloy, and a pair of extending walls 16 facing each other with a predetermined interval project from the back surface of the movable case 13. Although the movable case 13 and the extending wall 16 are integrally formed by die casting, those formed separately may be integrated by screwing or the like. A main rack 17 and a sub rack 18 are engraved on the inner surfaces of the extension walls 16 facing each other, and both the main rack 17 and the sub rack 18 extend in an arc shape around the shaft 2. As apparent from FIG. 3, the extension wall 16 is formed in a fan shape in a side view, and a main rack 17 is formed along the outer peripheral edge of the extension wall 16 farthest from the shaft 2. The sub racks 18 are engraved in parallel with a certain interval. As will be described in detail later, the drive gear 10 of the backlash removal gear 12 is engaged with the main rack 17, and the braking gear 11 of the backlash removal gear 12 is engaged with the sub rack 18.

  As shown in FIGS. 8 and 9, the backlash removing gear 12 described above has a braking gear rotatably supported by the drive gear 10 fixed to the support shaft 9 and the small-diameter portion 9 a on the distal end side of the support shaft 9. A gear 11, a ring-shaped friction plate 19 made of felt (nonwoven fabric) or the like interposed between the drive gear 10 and the brake gear 11, and a stop plate 20 locked to the small diameter portion 9 a of the support shaft 9. The stopper plate 20 and a coil spring 21 interposed between the brake gear 11 are configured. The brake gear 11 is pressed against the drive gear 10 via the friction plate 19 by the elastic force of the coil spring 21. ing. In the backlash removal gear 12 configured as described above, the coil spring 21 which is an elastic body presses the drive gear 10 and the brake gear 11 against the friction plate 19 interposed therebetween to obtain a friction torque. Therefore, a large friction torque can be generated even with the driving gear 10 and the braking gear 11 having a small diameter.

  The drive gear 10 is a gear having a larger diameter than the brake gear 11, and the drive gear 10 is engaged with the main rack 17, whereby the rotation of the motor 6 is changed from the drive gear 10 at the final stage of the reduction gear train 7 to the main rack. 17 is transmitted. Here, as shown in FIG. 10, the tooth width dimension W <b> 1 of the main rack 17 is set sufficiently larger than the tooth width dimension W <b> 2 of the sub rack 18, so that the drive gear 10 is buffered with the sub rack 18. It is possible to mesh with the main rack 17. Further, since the brake gear 11 is a gear having a smaller diameter than the drive gear 10, the brake gear 11 arranged coaxially with the drive gear 10 can be meshed with the sub rack 18 without buffering with the main rack 17. ing.

  As shown in FIG. 11, the main rack 17 has a large number of heat radiating grooves 17a cut out from the tooth bottom toward the inside (the outer peripheral edge side of the extending wall 16). If the length is h and the total tooth depth of the main rack 17 is H, the depth h of the heat radiating groove 17a is set in a range of 1 to 2 times the total tooth depth H of the main rack 17. Similarly, the sub rack 18 also has a large number of heat radiating grooves 18a cut out from the tooth bottom toward the inside (center side of the extending wall 16). The depth of the heat radiating grooves 18a is set to h1, Assuming that the total tooth depth of the sub rack 18 is H1, the depth h1 of the heat radiating groove 18a is set in the range of 1 to 2 times the total tooth depth H1 of the sub rack 18.

  Since the main rack 17 and the sub rack 18 each have a large number of heat radiating grooves 17a and 18a, a fin shape having a large heat sink cross-sectional area is formed on the extending wall 16 having good thermal conductivity. The movable case 13 can be provided with a heat sink function having a high heat dissipation effect. Therefore, the heat of the heat generating portion 15 built in the movable case 13 can be transferred to the heat sink portion of the extending wall 16 (the main rack 17 and the sub rack 18) without the need to add cooling parts such as cooling fans to the movable case 13. The heat can be efficiently radiated from the (formation region) to the outside. As described above, the depth h of the heat radiating groove 17a is set in a range of 1 to 2 times the total tooth depth H of the main rack 17, and similarly, the depth h1 of the heat radiating groove 18a is set to the total tooth height H1 of the sub rack 18. By setting it in the range of 1 to 2 times, the strength of the teeth of the main rack 17 and the sub rack 18 and the heat radiation effect can be secured in a well-balanced manner.

  Next, the operation of the in-vehicle display device configured as described above will be described.

  As shown in FIGS. 1 to 3, when the display main body 3 protrudes from the recess of the installation base material into the vehicle interior and is held in the standing posture, the drive gear 10 of the pair of backlash removal gears 12 corresponds to the corresponding main gear. The brake gear 11 that is coaxially arranged with the drive gear 10 meshes with the lowermost portion of the corresponding sub rack 18. Here, since a large friction torque due to the biasing force of the coil spring 21 acts between the driving gear 10 and the braking gear 11 constituting the backlash removing gear 12, the backlash and braking between the driving gear 10 and the main rack 17 are performed. Both backlashes between the gear 11 and the sub rack 18 are absorbed, and it is possible to reliably prevent the play from occurring in the display body 3 that is stopped in the standing posture.

  In addition, since the touch panel type display device 14 is used in the present embodiment, a pressing force is applied by the user to the display main body 3 that is stopped in the standing posture at the time of the touch operation. In addition, since a large friction torque is acting between the driving gear 10 and the braking gear 11, the display main body 3 is not easily displaced by the pressing force from the user, and it is possible to prevent the operation feeling at the time of touch input from being deteriorated.

  When the motor 6 rotates in either the forward or reverse direction in this state, the rotation is transmitted from the worm 8 to the drive gear 10 via the reduction gear train 7, so that the main rack 17 meshing with the drive gear 10 is moved to the motor 6. Driven by the rotational force of. At this time, as shown in FIG. 11, when the drive gear 10 meshed with the lowermost portion of the main rack 17 rotates clockwise (in the direction of arrow A), the main rack 17 and the sub rack 18 are included. Since the display body 3 (extension wall 16) rotates clockwise about the shaft 2 (in the direction of arrow B), the braking gear 11 meshing with the sub rack 18 is counterclockwise (in the direction of arrow C) opposite to the drive gear 10. Direction). Also at this time, a large friction torque acts between the drive gear 10 and the brake gear 11, and the brake gear 11 always rotates in the opposite direction while sliding with respect to the drive gear 10, so Both the backlash and the backlash between the braking gear 11 and the sub rack 18 are absorbed, and it is possible to reliably prevent the backlash of the display main body 3 during the rotation.

  As the meshing position of the main rack 17 with respect to the drive gear 10 moves upward as the motor 6 rotates in one direction as described above, the display body 3 gradually falls from the standing posture and the tilt angle is adjusted. When the drive gear 10 moves to a position where the drive gear 10 meshes with the uppermost portion of the main rack 17, the display main body 3 tilts to substantially the same plane as the surface of the installation base material and assumes a recumbent posture. The tilt angle of the display body 3 in the lying position can be set as appropriate.

  When the motor 6 rotates in the opposite direction to the above in the recumbent posture of the display body 3, the meshing position of the main rack 17 with respect to the drive gear 10 shifts from the uppermost part to the lowermost part. It can be made to protrude and face a user. Therefore, by controlling the rotation direction and rotation amount of the motor 6, the display main body 3 can be stopped at an arbitrary angular position of the standing posture and the recumbent posture, and the driving gear 10 and the braking gear of the backlash removal gear 12 are braked. Since a large friction torque always works between the gears 11, it is possible to suppress the occurrence of backlash not only when the display body 3 is stopped but also during the rotation.

  As described above, in the in-vehicle display device according to this embodiment, the backlash removal gear 12 is incorporated in the power transmission device that rotates the display main body 3 by the rotational force of the motor 6. A drive gear 10 whose removal gear 12 is rotationally driven by the power of the motor 6, a braking gear 11 coaxially arranged with the driving gear 10, and a friction plate 19 interposed between the driving gear 10 and the braking gear 11 Since the drive gear 10 and the brake gear 11 are constituted by a coil spring (elastic body) 21 that is elastically biased in a direction in which the drive gear 10 and the brake gear 11 are pressed against the friction plate 19, a large friction torque is generated between the drive gear 10 and the brake gear 11. Can be generated. Then, the main rack 17 and the sub rack 18 are formed on the extending wall 16 projecting from the back surface of the display body 3, and the drive gear 10 is engaged with the main rack 17 and the brake gear 11 is engaged with the sub rack 18. Therefore, when the drive gear 10 meshed with the main rack 17 is rotated in one direction by the power of the motor 6, the braking gear 11 meshed with the sub rack 18 is always slid against the drive gear 10 in the opposite direction. Thus, the backlash removal gear 12 can reliably prevent backlash between the drive gear 10 and the main rack 17 and backlash between the braking gear 11 and the sub rack 18.

  In the in-vehicle display device according to the present embodiment, a pair of extending walls 16 are provided on the back surface of the display main body 3, and a main rack 17 and a sub rack are respectively provided on the opposing inner surfaces of the extending walls 16. 18 is engraved, and the pair of backlash removal gears 12 that rotate synchronously with the power of the motor 6 are meshed with the racks 17 and 18 of the corresponding extension wall 16 so that the display main body 3 can be smoothly balanced. It can be rotated.

  In addition, a gear box 5 is provided on the support member 1 that pivotally supports the display body 3, and the gear box 5 is disposed in a space sandwiched between a pair of extending walls 16. Since the drive gear 10 of the backlash removal gear 12 is fixed to both ends of the support shaft 9 supported by the gear box 5, the motor 6 is installed in a limited installation space on the back surface of the display body 3 (movable case 13). To the backlash removal gear 12 can be compactly arranged.

  The final gear of the reduction gear train 7 housed in the gear box 5 is a drive gear 10 for the backlash removal gear 12, and is generated between the gears of the reduction gear train 7 by the backlash removal gear 12. Since backlash is absorbed, a standard gear without a backlash prevention function can be used as the remaining gear except the final gear. However, any stage gear other than the final stage of the reduction gear train 7 may be a backlash removal gear such as a scissor gear.

  In the above embodiment, the case where the power transmission device of the present invention is applied to a vehicle-mounted display device has been described. However, the field of application is not limited to this, for example, a recording / reproducing device for an optical recording medium. The present invention can be applied to all types of driving devices such as an optical pickup transfer mechanism that uses a rack and a driving gear to rotate or linearly move a movable body.

  In the above-described embodiment, the rotation type in-vehicle display device in which the display main body 3 is pivotally supported by the support member 1 has been described. However, the lift type in which the display main body is slidably supported by the support member. In such a case, the main rack and the sub rack may be extended in a straight line.

1 support member 2 axis 3 display body (movable body)
DESCRIPTION OF SYMBOLS 4 Power transmission device 5 Gear box 6 Motor 7 Deceleration gear train 8 Worm 9 Support shaft 10 Drive gear 11 Braking gear 12 Backlash removal gear 13 Movable case 13a Opening part 14 Display apparatus 14a Display screen 15 Heating part 16 Extension wall 17 Main Rack 17a Heat radiation groove 18 Sub rack 18a Heat radiation groove 19 Friction plate 20 Stop plate 21 Coil spring (elastic body)

Claims (7)

  A movable body that is movably supported by the support member, a main rack and a sub rack that are provided on the movable body and face each other in parallel; a drive gear that is pivotally supported by the support member and rotates using a motor as a drive source; The brake gear arranged coaxially with the drive gear, the friction plate interposed between the drive gear and the brake gear, and the elastic force in the direction in which the drive gear and the brake gear are pressed against the friction plate A power transmission device comprising: an elastic body for energizing, wherein the drive gear is engaged with the main rack, and the brake gear is engaged with the sub rack.   2. The reduction gear train comprising a plurality of gears including the drive gear is interposed between the motor and the main rack, and the final gear of the reduction gear train is the drive gear. A power transmission device characterized by that.   3. The movable body according to claim 2, wherein the movable body is rotatably supported by the support member, and the main rack and the sub rack extend in an arc shape around the rotation axis of the movable body. Power transmission device.   4. The main rack and the sub rack according to claim 3, wherein a pair of extending walls facing each other with a predetermined interval are provided on the back surface of the movable body, and the extending surfaces of the extending walls are opposed to each other. A power transmission device is formed.   5. The gear box according to claim 4, wherein a gear box that houses the reduction gear train is disposed between the pair of extending walls, and the drive gear is fixed to both ends of a support shaft that is pivotally supported by the gear box. A power transmission device characterized by that. In a vehicle-mounted display device comprising a display body having a display screen and a power transmission device for moving the display body at two different positions,
The power transmission device includes a driving gear that rotates using a motor as a driving source, a braking gear that is arranged coaxially with the driving gear, a friction plate interposed between the driving gear and the braking gear, An elastic body that elastically biases the drive gear and the braking gear in a direction in which the brake gear is pressed against the friction plate, and is provided with a main rack and a sub rack that extend in parallel to the display main body, An in-vehicle display device characterized in that the drive gear is engaged and the brake gear is engaged with the sub rack.   7. The display panel according to claim 6, wherein a pair of extending walls facing each other with a predetermined interval are provided on the back surface of the display main body, and the main rack and the sub rack are respectively disposed on opposing inner surfaces of the extending walls. An in-vehicle display device characterized in that is formed.