Sliding door drive device

Provided is a sliding door drive device enabling suppression of bulging against a body panel being a fixing target. The sliding door drive device includes a long guide frame, a first driven pulley and a second driven pulley being supported at both ends of the guide frame in a longitudinal direction, respectively, a belt being wrapped around the first driven pulley and the second driven pulley, and a belt drive part driving the belt. The guide frame includes a guide wall guiding the belt between the first driven pulley and the second driven pulley. The sliding door drive device further includes a sliding plate being placed at a position sandwiching the belt with an inner side of a curved part of the guide wall, and sliding on the driven belt.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application 2021-144031, filed on Sep. 3, 2021 and Japanese Patent Application 2021-032564, filed on Mar. 2, 2021, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to a sliding door drive device.

BACKGROUND DISCUSSION

A door opening-closing device is described in JP2019-100081A (Reference1) as a sliding door drive device opening and closing a sliding door of a vehicle. The door opening-closing device includes a belt guide part extending along a guide rail, two timing pulleys provided at the front end and the rear end of the belt guide part, respectively, a belt wrapped around the two timing pulleys, and a pressing pulley pressing the belt down toward the belt guide part.

The guide rail includes a linear part extending in a lengthwise direction and a curved part curved from the front end of the linear part toward a cabin. Therefore, the belt guide part also includes a linear part associated to the linear part of the guide rail and a curved part associated to the curved part of the guide rail. The pressing pulley is provided in the curved part of the belt guide part. Specifically, the pressing pulley prevents the belt from being driven in a state of being apart from the curved part of the belt guide part.

When a door opening-closing device as described above is fixed to a body panel of a vehicle, the pressing pulley is positioned between the belt guide part and the body panel. Therefore, a vehicle as described above needs to be provided with a recessed part on the body panel for avoiding interference by the pressing pulley.

A need thus exists for a sliding door drive device which is not susceptible to the drawback mentioned above.

SUMMARY

A sliding door drive device that solves the aforementioned problem is a sliding door drive device being fixed to a body panel of a vehicle and moving a sliding door of the vehicle in an opening direction and a closing direction. The sliding door drive device includes a long guide frame, a first driven pulley, a second driven pulley, a belt, a belt drive part, and a sliding part. The guide frame is curved in such a way that an end of the guide frame in the closing direction is positioned more inward in a vehicle widthwise direction than an end in the opening direction when the guide frame is fixed to the body panel. The first driven pulley and the second driven pulley are supported at both ends of the guide frame in a longitudinal direction, respectively. The belt is wrapped around the first driven pulley and the second driven pulley. The belt drive part drives the belt. The guide frame includes a guide wall guiding the belt between the first driven pulley and the second driven pulley. Denoting a curved part of the guide wall by a curved part and a surface of the guide wall facing the body panel by an inner side, the sliding part is placed at a position sandwiching the belt with the inner side of the curved part of the guide wall and slides on the driven belt.

DETAILED DESCRIPTION

An embodiment of a vehicle including a sliding door drive device (hereinafter also referred to as a “door drive device”) will be described below.

As illustrated inFIG.1, a vehicle10includes a vehicle body20, a sliding door30, and a door drive device40. In the following description, a vehicle widthwise direction is also referred to as a “widthwise direction,” and a vehicle lengthwise direction is also referred to as a “lengthwise direction,” and a vehicle vertical direction is also referred to as a “vertical direction.”

The vehicle body20includes a body panel22on which a door opening21is provided, an upper rail23placed above the door opening21, a center rail24placed behind the door opening21, and a lower rail25placed below the door opening21. The upper rail23, the center rail24, and the lower rail25are fixed to the body panel22. In the vertical direction, the upper rail23is positioned above the center rail24and the lower rail25, and the center rail24is positioned between the upper rail23and the lower rail25. The upper rail23, the center rail24, and the lower rail25are members for defining an opening-closing direction of the sliding door30.

As illustrated inFIG.2, the body panel22is a side body panel constituting a side of the vehicle body20. While being hidden by the door drive device40inFIG.2, an insertion hole for passing part of components of the door drive device40in the widthwise direction is bored through the body panel22in a plate thickness direction. The center rail24includes a first rail24A extending forward, a second rail24B extending inward in the vehicle widthwise direction in an arc shape from the front end of the first rail24A toward the front, and a third rail24C extending linearly from the front end of the second rail24B. While illustration is omitted, each of the upper rail23and the lower rail25also includes structures associated to the first rail24A, the second rail24B, and the third rail24C. Accordingly, each of the upper rail23, the center rail24, and the lower rail25is curved in such a way that the front end is positioned inward relative to the rear end in the widthwise direction. The upper rail23, the center rail24, and the lower rail25being curved allows the sliding door30to move in the widthwise direction near a fully closed position. Note that the radius of curvature of the curved part of the center rail24is smaller compared with those of the upper rail23and the lower rail25. The reason is that when the radius of curvature of the curved part of the center rail24is increased, the length of the door opening21in the lengthwise direction decreases due to the front end of the center rail24extending further forward.

As illustrated inFIG.1, the sliding door30includes a door body31sized according to the door opening21, an upper hinge unit32placed in an upper part of the door body31, a center hinge unit33placed in a rear part of the door body31, and a lower hinge unit34placed in a lower part of the door body31.

The upper hinge unit32and the lower hinge unit34are positioned near the front end of the door body31, and the center hinge unit33is positioned near the rear end of the door body31. The center hinge unit33is positioned in a central part of the door body31in the vertical direction. The upper hinge unit32is engaged with the upper rail23in such a way as to be movable along the upper rail23. The center hinge unit33is engaged with the center rail24in such a way as to be movable along the center rail24. The lower hinge unit34is engaged with the lower rail25in such a way as to be movable along the lower rail25.

Then, by the upper hinge unit32, the center hinge unit33, and the lower hinge unit34moving relative to the upper rail23, the center rail24, and the lower rail25, respectively, the sliding door30opens and closes between a fully closed position where the door opening21is fully closed and a fully opened position where the door opening21is fully opened. The sliding door30opens by moving backward and closes by moving forward, according to the present embodiment. In other words, an opening direction of the sliding door30is backward, and a closing direction of the sliding door30is forward. The sliding door30may open by moving forward and close by moving backward in another embodiment.

Door Drive Device40

As illustrated inFIG.3toFIG.5, the door drive device40includes a guide frame50, a belt drive part61, a drive pulley62, two pressing pulleys631and632, two driven pulleys641and642, a cover65, a belt66, a connector67, a protection plate68, and a sliding plate70.

The door drive device40is fixed to the body panel22along the center rail24at a position vertically aligned with the center rail24. Then, the door drive device40moves the sliding door30in the opening direction and the closing direction. In the following description, fixing the door drive device40to the body panel22is also referred to as “mounting the door drive device40on the vehicle body20.”

As illustrated inFIG.3andFIG.4, the guide frame50has a long form, similarly to the center rail24. Specifically, when mounted on the vehicle body20, the guide frame50in curved in such a way that the front end is positioned inward relative to the rear end in the widthwise direction.

In the following description, a part extending forward in the guide frame50is referred to as a “first linear part50A,” a part extending inward in the widthwise direction in an arc shape from the front end of the first linear part50A toward the front is referred to as a curved part50B, “and a part extending linearly from the front end of the curved part50B is referred to as a second linear part50C,” as illustrated inFIG.3andFIG.4. The first linear part50A is longer than the curved part50B and the second linear part50C, and the curved part50B and the second linear part50C have an equal length. In terms of a relation with the opening-closing direction of the sliding door30, the front end of the guide frame50is an end in the closing direction, and the rear end of the guide frame50is an end in the opening direction.

As illustrated inFIG.4andFIG.6, the guide frame50includes a bottom wall51, an upper wall52, a guide wall53, a housing part54, a support wall55, a retention wall56, and a fixing part57. For example, the guide frame50is made of a resin material and is formed by using a metal mold.

As illustrated inFIG.4, the bottom wall51, the upper wall52, and the guide wall53are long curved members, similarly to the center rail24. The bottom wall51connects to the lower end of the guide wall53, and the upper wall52connects to the upper end of the guide wall53. In other words, the bottom wall51and the upper wall52sandwich the guide wall53. The length of each of the bottom wall51and the upper wall52in a longitudinal direction is slightly longer than the length of the guide wall53in the longitudinal direction. As illustrated inFIG.6, the upper wall52includes two contact parts521protruding along a radial direction of the curved part50B in the curved part50B. The two contact parts521are positioned with a space in between in the longitudinal direction of the guide frame50.

In the following description, a surface of the guide wall53facing inward in the widthwise direction is referred to as an “inner side,” and a surface of the guide wall53facing outward in the widthwise direction is referred to as an “outer side.” The inner side is a surface facing the body panel22when the door drive device40is mounted on the vehicle body20.

As illustrated inFIG.4, the housing part54is integrated with the upper wall52and the guide wall53at a position closer to the front end than the central part of the guide frame50in the longitudinal direction. The housing part54includes an enclosure541housing the drive pulley62and the two pressing pulleys631and632, and a flange542extending from an edge of the enclosure541. When the door drive device40is mounted on the vehicle body20, the enclosure541is positioned inside the body panel22through the insertion hole, and the flange542is positioned outside the body panel22.

As illustrated inFIG.6, the support wall55extends upward from the curved part50B of the bottom wall51. In other words, the support wall55faces the inner side of the curved part50B of the guide wall53. Denoting a direction in which the support wall55extends by a height direction, the support wall55is slightly curved in a plan view in the height direction. A surface of the support wall55facing the guide wall53extends in the vertical direction. On the other hand, a surface of the support wall55facing the body panel22when the door drive device40is mounted on the vehicle body20is tilted relative to the vertical direction. In other words, the surface of the support wall55facing the body panel22extends along the outer surface of the body panel22.

As illustrated inFIG.4, the retention wall56extends upward from the first linear part50A of the bottom wall51. In other words, the retention wall56faces the first linear part50A of the guide wall53. The retention wall56is positioned between the rear end of the guide frame50and the housing part54in the longitudinal direction of the guide frame50. A surface of the retention wall56facing the guide wall53extends in the vertical direction. On the other hand, a surface of the retention wall56facing the body panel22when the door drive device40is mounted on the vehicle body20is tilted relative to an upward direction. In other words, the surface of the retention wall56facing the body panel22extends along the outer surface of the body panel22. While the guide frame50according to the present embodiment includes three retention walls56, the number of retention walls56may be arbitrarily changed. Then, the retention wall56guides movement of the belt66with the first linear part50A of the guide frame50.

The fixing part57extends upward from the upper wall52. A plurality of fixing parts57are provided with a space in between in the longitudinal direction of the guide frame50. The fixing part57is a part through which fastening members such as a screw and a bolt pass when the door drive device40is mounted on the vehicle body20, in other words, when the guide frame50is fixed to the body panel22.

As illustrated inFIG.3, the belt drive part61includes a motor611, an output shaft612to which motive power of the motor611is output, and a case613housing components of the belt drive part61. The belt drive part61includes, in the case613, an unillustrated speed reducer transferring motive power of the motor611to the output shaft612. An axial direction of the output shaft612is the widthwise direction. The output shaft612is connected to the drive pulley62. As illustrated inFIG.2, when the door drive device40is mounted on the vehicle10, the belt drive part61is placed inside the body panel22. In this respect, the belt drive part61may be considered to sandwich the body panel22with the guide frame50.

As illustrated inFIG.4, the drive pulley62, the first pressing pulley631, and the second pressing pulley632are housed in the housing part54of the guide frame50. Specifically, the drive pulley62, the first pressing pulley631, and the second pressing pulley632are rotatably supported by the enclosure541. At this time, the drive pulley62is positioned between the first pressing pulley631and the second pressing pulley632in the longitudinal direction of the guide frame50. Further, when the door drive device40is mounted on the vehicle body20, axes of rotation of the drive pulley62, the first pressing pulley631, and the second pressing pulley632extend in the widthwise direction. The drive pulley62is a toothed pulley.

As illustrated inFIG.4, the first driven pulley641is rotatably supported at the front end of the guide frame50in the longitudinal direction. Specifically, the first driven pulley641is supported between the front end of the bottom wall51in the longitudinal direction and the front end of the upper wall52in the longitudinal direction. The second driven pulley642is rotatably supported at the rear end of the guide frame50in the longitudinal direction. Specifically, the second driven pulley642is supported between the rear end of the bottom wall51in the longitudinal direction and the rear end of the upper wall52in the longitudinal direction. In these respects, the bottom wall51and the upper wall52may be considered to sandwich the guide wall53in an axial direction of the first driven pulley641and the second driven pulley642. Furthermore, the guide wall53may be considered to be positioned between the first driven pulley641and the second driven pulley642.

When the door drive device40is mounted on the vehicle body20, axes of rotation of the first driven pulley641and the second driven pulley642extend in the vertical direction. In other words, the axes of rotation of the first driven pulley641and the second driven pulley642have a skew positional relation with axes of rotation of the drive pulley62, the first pressing pulley631, and the second pressing pulley632. The first driven pulley641and the second driven pulley642are idlers.

The cover65is a part covering the drive pulley62, the first pressing pulley631, and the second pressing pulley632that are housed in the housing part54. The cover65includes a through-hole651for connecting the output shaft612of the belt drive part61to the drive pulley62. The cover65is fixed to the housing part54of the guide frame50.

The belt66is a toothed belt made of an elastomer such as rubber or resin. The belt66is wrapped around the drive pulley62, the two pressing pulleys631and632, and the two driven pulleys641and642in a state of surrounding the guide wall53of the guide frame50. As illustrated inFIG.4, the axes of rotation of the drive pulley62and the two pressing pulleys631and632, and the axes of rotation of the two driven pulleys641and642have a skew positional relation, according to the present embodiment. Therefore, as illustrated inFIG.5, twists occur in the belt66around a part where the belt66is wrapped around the drive pulley62and the two pressing pulleys631and632. Specifically, a twist occurs between the pressing pulley631and the sliding plate70, and a twist occurs between the pressing pulley632and the retention wall56in the belt66.

As illustrated inFIG.3, the connector67is a bracket for fixing the center hinge unit33of the sliding door30to the belt66. Specifically, one end of the connector67is fixed to the center hinge unit33, and the other end is fixed to the bracket.

For example, the protection plate68is formed by pressing a metal plate, as illustrated inFIG.3. The protection plate68is fixed to the second linear part50C of the upper wall52of the guide frame50from above. When the protection plate68is fixed to the guide frame50, the belt66is covered by the protection plate68in the horizontal direction. Thus, the protection plate68suppresses the belt66guided along the second linear part50C of the guide frame50coming in contact with a foreign substance.

As illustrated inFIG.6, the sliding plate70includes a body part71supported by the support wall55of the guide frame50, two extension parts72extending in such a way as to avoid the support wall55of the guide frame50, two engaging parts73engaged with the upper wall52of the guide frame50, and a locking part74engaged with the bottom wall51of the guide frame50. For example, the sliding plate70is formed by pressing a metal plate such as a stainless plate. The sliding plate70is an example of a “sliding part.”

The body part71is rectangular when viewed from a plate thickness direction. The body part71is slightly curved in such a way as to form an arc shape in a plan view. Specifically, the body part71is curved at a curvature equal to that of the curved part50B of the guide wall53of the guide frame50in a plan view. One end of the body part71in a transverse direction is slightly crooked across the body part71in the longitudinal direction. The two extension parts72extend from both ends of the body part71in the longitudinal direction, respectively. Each of the two extension parts72extends in a direction slightly tilted relative to the longitudinal direction of the body part71. In a plan view of the sliding plate70, each of the two extension parts72is tilted in a direction with an increased degree of curving relative to the body part71. The two engaging parts73extend in the transverse direction of the body part71on both sides of the body part71in the longitudinal direction, respectively. The two locking parts74extend from the front edges of the two extension parts72in the transverse direction of the body part71, respectively. In terms of a relation with the vehicle10, the two engaging parts73extend upward, and the two locking parts74extend downward.

As illustrated inFIG.7andFIG.8, the sliding plate70is inserted into the guide frame50. Specifically, the sliding plate70is inserted between the curved part50B of the guide wall53and the support wall55. At this time, the sliding plate70is elastically deformed slightly. Thus, the sliding plate70is placed at a position sandwiching the belt66with the inner side of the curved part50B of the guide wall53. In other words, the sliding plate70is supported by the guide frame50.

In a situation in which the sliding plate70is supported by the guide frame50, the body part71of the sliding plate70is in surface contact with the support wall55, as illustrated inFIG.8andFIG.9. In other words, the body part71of the sliding plate70is positioned between the support wall55and the belt66.

As illustrated inFIG.8andFIG.10, the two engaging parts73of the sliding plate70are engaged with two contact parts521of the upper wall52of the guide frame50, respectively. When the sliding plate70is inserted into the guide frame50, the two engaging parts73of the sliding plate70are elastically deformed slightly. Then, the two engaging parts73of the sliding plate70are placed below the two contact parts521of the upper wall52of the guide frame50, respectively. As a result, the sliding plate70is sandwiched between the two engaging parts73and the bottom wall51in the vertical direction.

As illustrated inFIG.6andFIG.11, the two locking parts74of the sliding plate70are locked to the bottom wall51of the curved part50B. At this time, while the support wall55of the guide frame50is positioned closer to the body panel22than the body part71of the sliding plate70, the two locking parts74of the sliding plate70are positioned closer to the body panel22than the bottom wall51of the guide frame50. At this time, the sliding plate70sandwiches the guide frame50by restoring force.

Thus, the sliding plate70is firmly supported on the guide frame50without using a fastening member such as a screw. As a result, the sliding plate70can press the belt66down toward the curved part50B of the guide wall53.

Operation of the present embodiment will be described.

As illustrated inFIG.3, when the sliding door30is opened, the belt66is driven in such a way that the connector67moves backward. On the other hand, when the sliding door30is closed, the belt66is driven in such a way that the connector67moves forward. In a situation in which the belt66is driven, the belt66slides on the sliding plate70, as illustrated inFIG.7. In other words, the belt66moves in one direction and in the other direction between the inner side of the guide wall53and the sliding plate70, in the curved part50B of the guide frame50. Thus, the sliding plate70suppresses the belt66interfering with the body panel22.

Effects of the present embodiment will be described.(1) The door drive device40includes the sliding plate70sliding on the driven belt66instead of a pulley rotating according to the driven belt66, as a structure preventing interference between the belt66and the body panel22. Therefore, the door drive device40enables reduction in bulging against the body panel22since a structure rotatably supporting a pulley is unnecessary.(2) The sliding plate70is plate shaped. Therefore, the structure of the door drive device40can be simplified compared with, for example, a case of using a plurality of pins as the “sliding part.”(3) As illustrated inFIG.9, the sliding plate70is positioned between the curved part50B of the guide wall53and the support wall55and specifically between the belt66and the support wall55, in the door drive device40. In other words, on the basis of the sliding plate70, the support wall55is positioned in a direction in which reaction force from the belt66acts. Therefore, the sliding plate70is resistant to displacement toward the body panel22even when the reaction force from the belt66acts. Accordingly, the door drive device40enables stabilization of the posture of the sliding plate70relative to the guide frame50.(4) As illustrated inFIG.9, the support wall55of the guide frame50has a shape running along the outer surface of the body panel22. Therefore, the support wall55of the guide frame50can be in surface contact with the outer surface of the body panel22. Accordingly, reaction force from the belt66acting on the sliding plate70can be received not only by the support wall55but also by the body panel22. Accordingly, the door drive device40enables suppression of load concentration on the support wall55.(5) As illustrated inFIG.7andFIG.10, the two engaging parts73of the sliding plate70are engaged with the contact parts521of the upper wall52of the guide frame50. Specifically, two engaging parts73of the sliding plate70are engaged with the contact part521of the upper wall52of the guide frame50from below. Therefore, movement of the sliding plate70in the vertical direction is restricted by the bottom wall51and the upper wall52of the guide frame50. Accordingly, the door drive device40enables stabilization of the posture of the sliding plate70.(6) As illustrated inFIG.7andFIG.11, the two locking parts74of the sliding plate70are locked to the bottom wall51of the guide frame50. Therefore, the door drive device40enables stabilization of the posture of the sliding plate70in the plate thickness direction.

The present embodiment may be modified and implemented as follows. The present embodiment and the following modified examples may be implemented in combination without technically contradicting one another.The belt66may be changed to a belt80illustrated inFIG.12. The belt80is a toothed belt, similarly to the aforementioned embodiment. As illustrated inFIG.12, the belt80includes a belt body81, a plurality of core wires82, a first covering layer83, and a second covering layer84. Each of the belt body81, the core wire82, the first covering layer83, and the second covering layer84is annular.

The belt body81is made of an elastomer such as rubber or resin. The belt body81is preferably made of a material with high durability and high abrasion resistance. A material of an elastomer constituting a part on the tooth side of the belt body81and a material of an elastomer constituting a part on the back side may be different. The core wire82is a reinforcing member of the belt body81. The core wire82is preferably made of a material with high strength against tension, such as resin fiber and metal. The core wires82are embedded in the belt body81in a state of being aligned in a widthwise direction of the belt80.

The first covering layer83covers the tooth side surface of the belt body81, and the second covering layer84covers the back side surface of the belt body81. The first covering layer83is a so-called tooth cloth. The second covering layer84corresponds to an example of a “covering layer” including a sliding surface80S sliding on the sliding plate70and the like. The first covering layer83and the second covering layer84are cloth-formed members made of synthetic fiber such as nylon. A coefficient of friction between the second covering layer84and the sliding plate70is lower than a coefficient of friction between the belt body81and the sliding plate70. In other words, a coefficient of friction between the material of the first covering layer83and the second covering layer84, and the metal constituting the sliding plate70is lower than a coefficient of friction between the elastomer constituting the belt body81and the metal constituting the sliding plate70. The first covering layer83and the second covering layer84are preferably made of a material with self-lubricity. A coefficient of friction in the present embodiment refers to a coefficient of kinetic friction.

For example, when the belt80is manufactured through a vulcanization process, it is preferable to bring components of the belt80into intimate contact with each other in the vulcanization process. Therefore, the core wire82, the first covering layer83, and the second covering layer84preferably undergo a pretreatment for improving adhesion with the elastomer constituting the belt body81before the vulcanization process.

When the sliding door30is opened and closed, sliding resistance is generated between the sliding surface80S of the belt80and the sliding plate70, or sliding resistance is generated between the sliding surface80S of the belt80and the retention wall56. In the aforementioned modified example, what slides on the sliding plate70in the belt80is the second covering layer84having a relatively low coefficient of friction with metal. Accordingly, the aforementioned modified example can reduce sliding resistance generated, for example, between the driven belt80and the sliding plate70.

When the twisted belt80slides on the sliding plate70or the like, only part of the belt80easily slides on the sliding plate70compared with a case of the untwisted belt80sliding on the sliding plate70or the like. Therefore, when the twisted belt80slides on the sliding plate70or the like, the belt80may be partially abraded. In this respect, the belt80includes the second covering layer84having a relatively low coefficient of friction with metal. Therefore, the belt80is resistant to partial abrasion even when the twisted belt80slides on the sliding plate70or the like.

As described in the aforementioned embodiment, the radius of curvature of the curved part of the center rail24is smaller compared with those of the upper rail23and the lower rail25. Therefore, the radius of curvature of the curved part50B of the guide frame50of the door drive device40also decreases. As a result, sliding resistance between the driven belt80and the sliding plate70also tends to increase. Accordingly, an effect of suppressing sliding resistance by providing the second covering layer84in the belt80may be considered to be enhanced, according to the aforementioned modified example.The door drive device40may include a pulley rotating according to the driven belt66in place of the sliding plate70, as a structure preventing interference between the belt66and the body panel22. In this case, when the belt66is replaced with the belt80according to a modified example, sliding resistance generated, for example, between the driven belt80and the aforementioned pulley can be reduced.The guide frame50may not include the support wall55. In this case, the sliding plate70is preferably fixed to the bottom wall51or the upper wall52of the guide frame50.The sliding plate70may be replaced with a pin or the like slidable on the belt66. In this case, the pin corresponds to an example of the “sliding part.”The support wall55of the guide frame50may function as the “sliding part.” In this case, a material of the support wall55is preferably selected in such a way that the support wall55is not abraded due to sliding on the belt66.The sliding plate70may be integrated with the support wall55of the guide frame50when the guide frame50is resin formed. Thus, the sliding plate70can be more firmly fixed to the guide frame50.For example, the sliding plate70may be fixed to the guide frame50by using fastening members such as a screw and a bolt or may be glued to the guide frame50by using an adhesive.The shape of the sliding plate70may be appropriately changed. For example, the sliding plate70may not include a structure associated to the engaging part73or may not include a structure associated to the locking part74.The sliding plate70may be fixed to the guide frame50by providing a hole in the bottom wall51of the guide frame50and inserting the sliding plate70into the hole.The door drive device40may be installed on the body panel22along the upper rail23or may be installed on the body panel22along the lower rail25.

A sliding door drive device that solves the aforementioned problem is a sliding door drive device being fixed to a body panel of a vehicle and moving a sliding door of the vehicle in an opening direction and a closing direction. The sliding door drive device includes a long guide frame, a first driven pulley, a second driven pulley, a belt, a belt drive part, and a sliding part. The guide frame is curved in such a way that an end of the guide frame in the closing direction is positioned more inward in a vehicle widthwise direction than an end in the opening direction when the guide frame is fixed to the body panel. The first driven pulley and the second driven pulley are supported at both ends of the guide frame in a longitudinal direction, respectively. The belt is wrapped around the first driven pulley and the second driven pulley. The belt drive part drives the belt. The guide frame includes a guide wall guiding the belt between the first driven pulley and the second driven pulley. Denoting a curved part of the guide wall by a curved part and a surface of the guide wall facing the body panel by an inner side, the sliding part is placed at a position sandwiching the belt with the inner side of the curved part of the guide wall and slides on the driven belt.

The sliding door drive device with the aforementioned structure can open and close the sliding door by transferring motive power to the sliding door through the belt. The sliding door drive device includes the sliding part sliding on the driven belt instead of a pressing pulley rotating relative to the driven belt, as a structure preventing the belt from interfering with the body panel. Therefore, the sliding door drive device enables reduction in bulging against the body panel since a structure rotatably supporting a pulley is unnecessary.

In the aforementioned sliding door drive device, the sliding part may be a plate-shaped sliding plate curved along the curved part.

The structure of the aforementioned sliding door drive device can be simplified compared with a case of, for example, using a plurality of pins as a sliding part.

In the aforementioned sliding door drive device, denoting a direction in which axes of rotation of the first driven pulley and the second driven pulley extend by an axial direction, the guide frame may include a bottom wall and an upper wall sandwiching the guide wall in the axial direction across the guide frame in the longitudinal direction, and a support wall extending from the bottom wall in such a way as to face the inner side of the curved part of the guide wall and supporting the sliding plate in a state of being in contact with the sliding plate.

In the sliding door drive device with the aforementioned structure, the sliding plate is positioned between the curved part of the guide wall and the support wall and particularly between the belt and the support wall. In other words, on the basis of the sliding plate, the support wall is positioned in a direction in which reaction force from the belt acts. Therefore, the sliding plate is resistant to displacement in a direction in which the reaction force acts even when the reaction force from the belt acts. Accordingly, the sliding door drive device enables stabilization of a posture of the sliding plate relative to the guide frame.

In the aforementioned sliding door drive device, denoting a direction in which the support wall extends from the bottom wall by a height direction, the upper wall of the guide frame may include a contact part sandwiching the sliding plate with the bottom wall in the height direction.

The sliding door drive device with the aforementioned structure enables stabilization of a posture of the sliding plate relative to the guide frame in the height direction.

In the aforementioned sliding door drive device, the sliding plate may include a body part supported by the support wall, and a locking part locked to the bottom wall on both sides of the body part in the longitudinal direction.

In the sliding door drive device with the aforementioned structure, the locking part of the sliding plate is locked to the bottom wall of the guide frame. Therefore, the sliding door drive device enables further stabilization of the posture of the sliding plate relative to the guide frame.

In the aforementioned sliding door drive device, denoting a surface of the belt sliding on the sliding part by a sliding surface, the belt may include a belt body made of an elastomer, and a covering layer including the sliding surface and covering the belt body. A coefficient of friction between the covering layer and the sliding part may be lower than a coefficient of friction between the belt body and the sliding part.

Sliding resistance is generated between the belt and the sliding part when the sliding door is opened and closed. In this respect, the coefficient of friction between the covering layer and the sliding part is lower than the coefficient of friction between the belt body and the sliding part in the sliding door drive device with the aforementioned structure. Accordingly, the sliding door drive device enables reduction in sliding resistance generated between the belt and the sliding part compared with a case of not providing the covering layer in the belt.

The aforementioned sliding door drive device may further include a drive pulley being supported by the guide frame and being driven by the belt drive part. An axis of rotation of the drive pulley may have a skew positional relation with axes of rotation of the first driven pulley and the second driven pulley. The belt twisted between the first driven pulley and the second driven pulley may be wrapped around the drive pulley.

When the twisted belt slides on the sliding part or the like, only part of the belt easily slides on the sliding part, compared with a case of the untwisted belt sliding on the sliding part or the like. Therefore, when the twisted belt slides on the sliding part or the like, the belt may be partially abraded. In this respect, the belt includes the covering layer having a relatively low coefficient of friction with the sliding part in the sliding door drive device with the aforementioned structure. Therefore, the belt is resistant to partial abrasion even when the twisted belt slides on the sliding part or the like.

In the aforementioned sliding door drive device, the vehicle may include an upper rail placed above a door opening to be opened and closed by the sliding door, a lower rail placed below the door opening, and a center rail placed at a position advanced from the door opening in the opening direction and between the upper rail and the lower rail in a vertical direction. The upper rail, the lower rail, and the center rail may define an opening-closing direction of the sliding door. The guide frame may be fixed to the body panel in such a way as to run along the center rail.

The aforementioned sliding door drive device enables suppression of bulging against the body panel being a fixing target of the sliding door drive device.