This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2013-044568, filed on Mar. 6, 2013, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a door latch device.
2. Description of the Related Art
A door latch device that holds a door of a vehicle in a closed state includes a base plate having a striker entry groove entered by a striker, a latch rotatably supported on a latch shaft provided on the base plate, and a ratchet rotatably supported on a ratchet shaft provided on the base plate. The latch moves between a full-latch position in which the latch constrains the striker that has entered the striker entry groove by engaging with the striker, and an open position in which the latch releases the constrained striker. The ratchet moves between an engagement position in which the ratchet engages with the latch so as to hold the latch in the full-latch position, and a disengagement position in which the ratchet releases the engagement.
There are such kind of door latch devices (refer, for example, to Japanese Translation of PCT International Application Publication No. 2007-506879) that include a linkage mechanism that is operated by power from a driving member to move the latch to the full-latch position when the latch is moved from the open position into a half-latch position by, for example, a pressing load from the striker that has entered the striker entry groove.
The linkage mechanism includes a first link rotatably supported on a fixed shaft provided on the base plate, a second link rotatably supported on the latch shaft, and an intermediate link that is rotatably connected to the first link by a first link shaft and rotatably connected to the second link by a second link shaft. In the linkage mechanism, introducing the power from the driving member to the first link rotates the second link about the latch shaft so as to move the latch to the full-latch position.
In the door latch device disclosed in Japanese Translation of PCT International Application Publication No. 2007-506879, the first link, the second link, the intermediate link, and the driving member are arranged in an area on one side of a plane, serving as a boundary, including a shaft center of the fixed shaft and a shaft center of the latch shaft (hereinafter also called “boundary plane”). This necessitates a large space for arranging the linkage mechanism and the driving member on one area side of the boundary plane, and thus makes it difficult to reduce the size of the door latch device.
According to one aspect of the present invention, a door latch device includes: a base plate that has a portion defining a striker entry groove entered by a striker; a latch that is rotatably supported on a latch shaft provided on the base plate and that moves between a full-latch position in which the latch constrains the striker that has entered the striker entry groove by engaging with the striker, and an open position in which the latch releases the constrained striker; a ratchet that is rotatably supported on a ratchet shaft provided on the base plate and that moves between an engagement position in which the ratchet engages with the latch so as to hold the latch in the full-latch position, and a disengagement position in which the ratchet releases the engagement; and a linkage mechanism that is operated by power from a driving member to move the latch to the full-latch position when the latch moving from the open position toward the full-latch position reaches a half-latch position lying between the open position and the full-latch position, wherein the linkage mechanism comprises a first link that is rotatably supported on a fixed shaft provided on the base plate, a second link that is rotatably supported on the latch shaft, and an intermediate link that is rotatably connected to the first link by a first link shaft and rotatably connected to the second link by a second link shaft, and the linkage mechanism is configured such that, while the linkage mechanism moves the latch from the half-latch position into the full-latch position, the first link shaft moves in an area on one side of a plane serving as a boundary including a shaft center of the fixed shaft and a shaft center of the latch shaft, and the second link shaft moves in an area on the other side of the plane serving as the boundary.
The above and other features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.
An embodiment of a door latch device according to the present invention will be described below in detail with reference to the accompanying drawings. In all of the drawings for explaining the embodiment, components having the same functions will be given the same reference numerals, and repetition of description thereof will be omitted.
The door latch device of the present embodiment is mounted on a back door of a vehicle, and holds the back door in a closed state by constraining a striker provided on a vehicle body. As illustrated in
The case 1, the base plate 2, and the switch plate 3 are members that house such components as the latch 4 and the ratchet 5.
The case 1 is provided with a striker entry groove 1a entered by a striker S, an insertion hole into which one end of a latch shaft 11 is inserted, an insertion hole into which one end of a ratchet shaft 12 is inserted, an insertion hole into which one end of a support shaft (revolution shaft) 13 supporting the cam gear 8 is inserted, an insertion hole into which one end of a support shaft (fixed shaft) 14 supporting a worm wheel 902 of the worm gear 9 is inserted, and a motor fixing portion 1b for fixing the motor 10, for example.
The base plate 2 is provided with a striker entry groove 2a entered by the striker S, an insertion hole into which the other end of the latch shaft 11 is inserted, an insertion hole into which the other end of the ratchet shaft 12 is inserted, insertion holes into which the other ends of the support shafts 13 and 14 are inserted, and mounting portions 2b for mounting the door latch device on the back door, for example. The mounting portions 2b are provided with insertion holes into which bolts are inserted. Barred portions 2c are provided around the insertion holes.
The switch plate 3 is provided with a first switch SW1 that detects a position of the latch 4, a second switch SW2 that detects a position of the ratchet 5, a third switch SW3 that detects a position of the cam gear 8, and wires connected to the switches SW1 to SW3, for example. The wires connected to the switches SW1 to SW3 are connected to a control board via a cable. Each of the first, the second, and the third switches SW1, SW2, and SW3 is what is called a microswitch, and is turned on when a plunger (not illustrated) is pressed.
The latch 4 is rotatably supported on the latch shaft 11, and urged counterclockwise in
The ratchet 5 is rotatably supported on the ratchet shaft 12, and urged clockwise in
The linkage mechanism 6 operates so as to move the latch 4 that has moved from the open position into the half-latch position further into the full-latch position, and includes a first link 601, a second link 602, an intermediate link 603, a first link shaft 604, a second link shaft 605, and a retraction lever 606. The first link 601 is rotatably supported on the support shaft (fixed shaft) 14 provided on the base plate 2. The second link 602 is rotatably supported on the latch shaft 11. The intermediate link 603 is rotatably connected to the first link 601 by the first link shaft 604, and rotatably connected to the second link 602 by the second link shaft 605.
The first link 601, the second link 602, and the intermediate link 603 are arranged in a Z-shape so that, as illustrated in
The first link 601, the second link 602, and the intermediate link 603 are further arranged so that the ratchet 5 is included in the first area bounded by the first plane L1. Specifically, the first area serves as an area on the side including the ratchet 5 with respect to the first plane L1 serving as the boundary, and the first link shaft 604 is arranged in the first area.
The lengths of the first link 601, the second link 602, and the intermediate link 603 are set so that a movement of the first link 601 into a position of a dashed line 601′ by rotating counterclockwise in
The lengths of the first link 601, the second link 602, and the intermediate link 603 are further set so that, while the latch 4 is moved from the half-latch position into the full-latch position, the shaft center P3 of the first link shaft 604 and the shaft center P4 of the second link shaft 605 move in an area interposed between a second plane L2 and a third plane L3 illustrated in
The retraction lever 606 is engaged with the latch 4 when the latch 4 is moved from the half-latch position into the full-latch position, and is rotatably connected to the second link shaft 605. The retraction lever 606 extends from the second link shaft 605 and intersects the first plane L1 into the first area, and the extending portion thereof is provided with a retraction portion 606a and a cancel portion 606b. The retraction portion 606a is a portion that engages with a retraction engagement portion 4g of the latch 4 when the latch 4 has moved from the open position into the half-latch position. The cancel portion 606b is a portion that engages with the lever ratchet 7 and receives a pressing load from the lever ratchet 7 when the engagement between the retraction portion 606a and the latch 4 is released. The cancel portion 606b is provided at a tip of a portion extending from the second link shaft 605 so as to form a circular arc around the shaft center of the latch shaft 11 so that the retraction lever 606 can rotate about the latch shaft 11 together with the second link 602.
The retraction lever 606 is urged counterclockwise in
The lever ratchet 7 releases the engagement between the retraction portion 606a of the retraction lever 606 and the latch 4, and the engagement between the latch 4 and the ratchet 5, and is rotatably supported on the ratchet shaft 12. The lever ratchet 7 is provided with the retraction lever pressing portion 7a, a ratchet pressing portion 7b, a cam sliding contact portion 7c, and a cable connection portion 7d. The retraction lever pressing portion 7a is a portion that engages with the cancel portion 606b of the retraction lever 606, and presses the cancel portion 606b in the direction of moving the retraction portion 606a away from the latch 4 to rotate the retraction lever 606 about the second link shaft 605. The ratchet pressing portion 7b is a portion that presses a pressure receiving portion 5b of the ratchet 5 so as to move the ratchet 5 into a disengagement position. The cam sliding contact portion 7c is a portion that slidingly contacts a cam portion 802 of the cam gear 8 and receives a pressing force from the cam portion 802 on the occasion of releasing the engagement between the latch 4 and the ratchet 5. The cable connection portion 7d is a portion that connects a cable extending from a control lever for manual disengagement in the case of allowing the engagement between the latch 4 and the ratchet 5 to be released manually. The lever ratchet 7 is urged clockwise in
The cam gear 8 outputs power of the motor 10 transmitted via the worm gear 9 to the linkage mechanism 6 and the lever ratchet 7, and is rotatably supported on the support shaft (revolution shaft) 13. The cam gear 8 is provided with a gear portion 801, the cam portion 802, and a switching portion 803. The gear portion 801 meshes with a reduction gear portion 903 provided on the worm wheel 902. The cam portion 802 is a portion that revolves about the support shaft 13 as a result of rotation of the gear portion 801, and includes a first cam surface 802a that presses the first link shaft 604 and the lever ratchet 7 when the cam portion 802 revolves in the counterclockwise direction in
The cam gear 8 is arranged so that the first link shaft 604 is in a position overlapping a locus of the revolution of the cam portion 802 when the latch 4 is in the open position. Each of the first cam surface 802a and the second cam surface 802b of the cam portion 802 forms a spline surface.
The worm gear 9 transmits the power of the motor 10 at a reduced speed to the cam gear 8, and includes a worm 901 mounted on a rotary shaft 1001 of the motor 10, the worm wheel 902 meshing with the worm 901, and the reduction gear portion 903 provided so as to be integrated with the worm wheel 902.
While the latch 4 is in the open position, the cam gear 8 stands by in a first standby position in which the first cam surface 802a of the cam portion 802 first starts to press the first link shaft 604 when the cam gear 8 rotates in the first direction (counterclockwise direction) as illustrated in
Closing the back door while the latch 4 is in the open position causes the striker S to enter the striker entry grooves 1a and 2a and to press the pressure receiving portion 4c of the latch 4. The latch 4, receiving the pressing load from the striker S, rotates counterclockwise in
In the course of the movement of the latch 4 from the open position into the half-latch position, the position on which the end 19a of the switch lever 19 abuts changes from the first projecting portion 4f to a recessed portion 4h. The distance from the latch shaft 11 is smaller to the recessed portion 4h than to the first projecting portion 4f, so that the switch lever 19 rotates counterclockwise in
Then, arrival of the latch 4 in the half-latch position engages the half-latch latching portion 4d of the latch 4 with the latch engagement portion 5a of the ratchet 5, and the retraction portion 606a of the retraction lever 606 with the retraction engagement portion 4g of the latch 4, as illustrated in
The rotation of the cam gear 8 in the first direction from the first standby position causes the first cam surface 802a of the cam portion 802 to press the first link shaft 604, thus causing the first link 601 to rotate clockwise in
The latch 4 has, on a side surface thereof slidingly contacting the ratchet 5, a section between the half-latch latching portion 4d and the full-latch latching portion 4e that has a distance from the latch shaft 11 increasing toward the full-latch latching portion 4e. This causes the ratchet 5 to rotate clockwise in
Then, arrival of the latch 4 in the full-latch position engages the full-latch latching portion 4e of the latch 4 with the latch engagement portion 5a of the ratchet 5. At this time, the ratchet 5 rotates counterclockwise in
Thereafter, the cam gear 8 further rotates in the first direction, and then, the first cam surface 802a of the cam portion 802 comes apart from the first link shaft 604 as illustrated in
While the latch 4 is held in the full-latch position and the cam gear 8 stands by in the second standby position, pressing a door opening button provided in a vehicle interior causes the control board to operate the motor 10 so as to rotate the cam gear 8 in the first direction. The rotation of the cam gear 8 in the first direction from the second standby position causes the first cam surface 802a of the cam portion 802 to press the cam sliding contact portion 7c of the lever ratchet 7, rotating the lever ratchet 7 clockwise in
Thereafter, the cam gear 8 further rotates in the first direction, and then, the first cam surface 802a of the cam portion 802 comes apart from the cam sliding contact portion 7c of the lever ratchet 7. Then, the lever ratchet 7 rotates counterclockwise in
The movement of the latch 4 from the full-latch position into the open position turns on the first and the second switches SW1 and SW2. Then, when the cam gear 8 rotates in the first direction, and the switching portion 803 presses the plunger of the third switch SW3, the third switch SW3 is turned from off to on. When the third switch SW3 is turned from off to on while the first and the second switches SW1 and SW2 are on in this manner, the control board stops the motor 10. This stops the cam gear 8 in the first standby position, thus returning the door latch device into the state illustrated in
When the door opening operation is performed by directly moving the lever ratchet 7 without rotating the cam gear 8 placed in the second standby position, the door latch device of the present embodiment can also release the engagement between the latch 4 and the ratchet 5, and the engagement between the latch 4 and the retraction lever 606. In that case, when the ratchet 5 moves into the disengagement position and the second switch SW2 is turned on, the control board operates the motor 10 so as to rotate the cam gear 8 in the first direction. Then, when the cam gear 8 reaches the first standby position illustrated in
When the back door is closed, a situation could occur in which a foreign object such as clothes or baggage in the vehicle is pinched between the back door and the vehicle body, so that the latch 4 cannot be retracted into the full-latch position. The occurrence of such a situation causes the cam gear 8 to abnormally stop in the course of moving the latch 4 into the full-latch position, leading to an incomplete closed-door state in which the latch 4 is held between the half-latch position and the full-latch position.
When the cam gear 8 abnormally stops in the course of moving the latch 4 into the full-latch position, the door latch device of the present embodiment reverses the rotation of the motor 10 to rotate the cam gear 8 in the second direction. Rotating the cam gear 8 in the second direction, and thus separating the first cam surface 802a of the cam portion 802 from the first link shaft 604 holds the latch 4 in the half-latch position. Rotating further the cam gear 8 in the second direction from that state causes the second cam surface 802b provided on the cam portion 802 to press the cam sliding contact portion 7c of the lever ratchet 7, as illustrated in
When the cam sliding contact portion 7c of the lever ratchet 7 reaches the end of the second cam surface 802b, the cam sliding contact portion 7c abuts on the stopper portion 802c of the cam portion 802 and restricts the rotation of the cam gear 8 in the second direction. The restriction of the rotation of the cam gear 8 reverses again the rotation of the motor 10 to rotate the cam gear 8 in the first direction. Then, when the cam gear 8 reaches the first standby position illustrated in
As illustrated in
In the linkage mechanism 6 of the present embodiment, the first link 601, the second link 602, and the intermediate link 603 are arranged in a Z-shape. This arrangement can reduce the distance between the shaft center P1 of the support shaft (fixed shaft) 14 and the shaft center P2 of the latch shaft 11 while ensuring the amount of movement of the second link shaft 605 necessary for moving the latch 4 from the half-latch position into the full-latch position. In addition, by arranging the first link shaft 604 receiving the power from the cam gear 8 (driving member) in the area on the side including the ratchet 5 with respect to the first plane L1 serving as the boundary, the cam gear 8 can be arranged on the ratchet 5 side of the linkage mechanism 6. This can reduce the dimension in the depth direction (advancing/retreating direction of the striker S) of the door latch device required for arranging the linkage mechanism 6 and the cam gear 8, and thus can reduce the size of the door latch device.
In the door latch device of the present embodiment, the first link shaft 604 and the second link shaft 605 move between the second plane L2 that passes through the shaft center P1 of the support shaft 14 and is orthogonal to the first plane L1, and the third plane L3 that passes through the shaft center P2 of the latch shaft 11 and is orthogonal to the first plane L1. As a result, a dimension in the direction of a line segment connecting the shaft center P1 of the support shaft 14 and the shaft center P2 of the latch shaft 11 serves as the distance between the shaft center P1 of the support shaft 14 and the shaft center P2 of the latch shaft 11, so that the dimension in the depth direction of the door latch device can be further reduced.
In the door latch device of the present embodiment, the cam portion 802 revolves about the support shaft 13, and the first link shaft 604 is positioned within the locus of the revolution of the cam portion 802 when the latch 4 is in the open position. This allows the support shaft (revolution shaft) 13 supporting the cam gear 8 to be arranged near the first link 601, and can prevent the door latch device from increasing in size in the width direction (direction orthogonal to the depth direction).
The lever ratchet 7 rotatably supported on the ratchet shaft 12 and having the ratchet pressing portion 7b and the cam sliding contact portion 7c is arranged in the area on the side including the ratchet 5 with respect to the first plane L1 serving as the boundary. Thus, the cam portion 802 operating the linkage mechanism 6 can be used to move the ratchet 5 into the disengagement position. This allows the engagement between the latch 4 and the ratchet 5 to be released by the power from the motor 10, and can simplify the configuration for releasing the engagement.
The retraction lever 606 moving the latch 4 from the half-latch position into the full-latch position is rotatably connected to the second link shaft 605, and extends from the second link shaft 605 into the first area including the ratchet 5, in which the retraction portion 606a and the cancel portion 606b are provided on the retraction lever 606. The retraction lever 606 is urged by the coil spring 17 so that the direction of urging the rotation thereof about the second link shaft 605 is the same as the direction of urging the rotation of the latch 4 about the latch shaft 11. The retraction portion 606a of the retraction lever 606 is placed in the position that is moved closer to the latch shaft 11 by the rotation of the retraction lever 606 in the urged direction thereof. This allows the engagement and disengagement between the retraction portion 606a of the retraction lever 606 and the retraction engagement portion 4g of the latch 4 to be achieved by rotating the retraction lever 606 about the second link shaft 605. The cancel portion 606b of the retraction lever 606 is in engagement with the retraction lever pressing portion 7a of the lever ratchet 7, and, when the lever ratchet 7 moves the ratchet 5 into the disengagement position, the retraction lever pressing portion 7a presses the cancel portion 606b in the direction opposite to the direction of urging the retraction lever 606. This causes the retraction portion 606a of the retraction lever 606 to come apart from the retraction engagement portion 4g of the latch 4. This allows the lever ratchet 7 releasing the engagement between the latch 4 and the ratchet 5 to release also the engagement between the latch 4 and the retraction lever 606. This, in turn, can simplify the configuration for releasing the engagement between the latch 4 and the retraction lever 606, and can prevent the door latch device from increasing in size.
Further, the retraction lever 606 rotates together with the second link shaft 605 about the latch shaft 11 during the operation of the linkage mechanism 6. At that time, the retraction portion 606a of the retraction lever 606 in engagement with the retraction engagement portion 4g moves along the direction of movement of the latch 4 (retraction engagement portion 4g). This allows the latch 4 to be moved into the full-latch position by efficiently moving the retraction lever 606 during the operation of the linkage mechanism 6.
The cam portion 802 of the cam gear 8 can make a circle when revolving in the first direction, and while making one circle in the first direction, the first cam surface 802a presses individually once each of the first link shaft 604 and the cam sliding contact portion 7c of the lever ratchet 7. Therefore, by stopping the rotation of the cam gear 8 and making it stand by when the latch 4 has moved into the full-latch position and when the latch 4 has moved into the open position, the revolution of the cam gear 8 in the first direction can achieve the operation of moving the latch 4 from the half-latch position into the full-latch position, and the operation of moving the latch 4 from the full-latch position into the open position. The cam portion 802 is provided with the second cam surface 802b that can release the engagement between the latch 4 and the ratchet 5, and the engagement between the latch 4 and the retraction lever 606, via the lever ratchet 7 when the cam portions 802 revolves in the second direction. In addition, the end of the second cam surface 802b is provided with the stopper portion 802c that restricts the revolution of the cam portion 802 in the second direction in the state in which the second cam surface 802b presses the cam sliding contact portion 7c of the lever ratchet 7. This allows the latch 4 to be quickly returned into the open position when the cam gear 8 abnormally stops in the course of moving the latch 4 from the half-latch position into the full-latch position. The restriction of the revolution of the cam portion 802 in the second direction causes the cam portion 802 to revolve again in the first direction and stop in the first standby position. This allows the back door to be quickly opened and closed again when the latch 4 is placed in the incomplete closed-door state of being held between the half-latch position and the full-latch position.
The door latch device of the present embodiment connects the retraction lever 606 to the second link shaft 605, and engages the retraction portion 606a of the retraction lever 606 with the retraction engagement portion 4g of the latch 4 to move the latch 4 into the full-latch position. However, the method for moving the latch 4 into the full-latch position is not limited to the method using the retraction lever 606, but may be, for example, a method in which the second link 602 or the second link shaft 605 directly engages with the latch 4.
The first link shaft 604 of the linkage mechanism 6 and the cam sliding contact portion 7c of the lever ratchet 7 receiving the pressing load from the cam portion 802 only need to be arranged so as to be capable of individually performing the operation of moving the latch 4 from the half-latch position into the full-latch position, and the operation of releasing the engagement between the latch 4 and the ratchet 5. Specifically, the first link shaft 604 of the linkage mechanism 6 and the cam sliding contact portion 7c of the lever ratchet 7 are not limited to be arranged in the positional relation exemplified in the present embodiment, but only need to be arranged in a positional relation in which the first link shaft 604 and the cam sliding contact portion 7c of the lever ratchet 7 can be individually pressed when the cam portion 802 revolves in the first direction, and the cam sliding contact portion 7c can be pressed when the cam portion 802 revolves in the second direction. Therefore, the first link shaft 604 of the linkage mechanism 6 and the cam sliding contact portion 7c of the lever ratchet 7 can be arranged, for example, in the shaft center direction of the support shaft 13 so that a region of the locus of the revolution of the cam portion 802 overlapped by the first link shaft 604 overlaps a region of the locus of the revolution of the cam portion 802 overlapped by the cam sliding contact portion 7c. In that case, the first cam surface 802a of the cam portion 802 is divided into two in the shaft center direction of the support shaft 13, and one cam surface is treated as a retraction cam surface that presses the first link shaft 604 while the other cam surface is treated as a release cam surface that presses the cam sliding contact portion 7c of the lever ratchet 7. Displacing the apex of the retraction cam surface from the apex of the release cam surface by a predetermined angle about the shaft center of the support shaft 13 allows the first link shaft 604 and the cam sliding contact portion 7c to be individually pressed when the cam portion 802 revolves in the first direction. Further, providing the second cam surface 802b in a position corresponding to the release cam surface in the first cam surface 802a of the cam portion 802 allows the latch 4 to be promptly returned into the open position by revolving the cam portion 802 in the second direction when the cam gear 8 abnormally stops in the course of moving the latch 4 from the half-latch position into the full-latch position.
In the present embodiment, when the cam gear 8 rotates in the second direction, the rotation of the cam gear 8 is restricted by the abutment between the stopper portion 802c positioned at the end of the second cam surface 802b and the cam sliding contact portion 7c of the lever ratchet 7. However, without providing the stopper portion 802c, the cam gear 8 may be moved into the second standby position, and then may be rotated again in the first direction to be returned into the first standby position.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2013-044568 | Mar 2013 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
5423582 | Kleefeldt | Jun 1995 | A |
6079237 | Hochart | Jun 2000 | A |
6422615 | Roos | Jul 2002 | B1 |
7341290 | Torka | Mar 2008 | B2 |
20020070564 | Ohta | Jun 2002 | A1 |
20030080569 | Raymond et al. | May 2003 | A1 |
Number | Date | Country |
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2007-506879 | Mar 2007 | JP |
2004113655 | Dec 2004 | WO |
Entry |
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Notification of Reasons for Refusal Japanese Patent Application No. 2013-044568 dated Jul. 26, 2016 with English language translation. |
Number | Date | Country | |
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20140252783 A1 | Sep 2014 | US |