GB2304801A

GB2304801A - Latch device for a vehicle motorised sliding door

Info

Publication number: GB2304801A
Application number: GB9618139A
Authority: GB
Inventors: Tetsuro Mizuki; Hirofumi Watanabe; Yuji Yoda; Hitoshi Yokouchi
Original assignee: Mitsui Mining and Smelting Co Ltd
Current assignee: Mitsui Mining and Smelting Co Ltd
Priority date: 1995-09-01
Filing date: 1996-08-30
Publication date: 1997-03-26
Anticipated expiration: 2016-08-30
Also published as: GB2304801B; KR100218569B1; KR970016013A; GB9618139D0

Abstract

A powered sliding unit (6) attached to a vehicle body (2) slides a sliding door (1) from an open position to a half-latch position where a rear latch unit (88) fixed to the sliding door is initially engaged with a rear striker fixed to the vehicle body, and then a powered closing unit (89) provided to the sliding door moves the sliding door (1) from the half-latch position into a full-latch position where the rear latch unit (88) is completely engaged with the rear striker. The powered sliding unit (6) has a vertical base plate (25), a wire drum (26) rotatably attached to the base plate by a horizontal shaft (34), and a wire cable (7) for coupling the wire drum (26) with the sliding door (1). The powered sliding unit (6) is attached in an inner space inside of a rear outer side panel (3) of the vehicle body (2).

Description

LATCH DEVICE FOR VEHICLE SLIDING DOOR The present invention relates to a latch device for a vehicle sliding door, and in particular, to a latch device which has a powered sliding unit for sliding a door under the power of a first motor, and a powered closing unit for completely closing the sliding door under the power of a second motor.

Referring to Fig. 25, a conventional sliding door A which is attached to a vehicle body B so as to be slidable in a longitudinal or front-and-rear direction of the body B comprises a front latch unit D adapted to be engaged with a front striker C fixed to the vehicle body B and a rear latch unit F adapted to be engaged with a rear striker E fixed to the vehicle body B.

During closing of the sliding door A, the door A moves, at first, along a side surface of the vehicle body B in the direction of the arrow X, and the front latch unit D engages with the front striker C. Then, the sliding door A moves in the direction of the arrow Y orthogonal to the direction of the arrow X, and the rear latch unit F engages with the rear striker E. That is, when the rear latch unit F is engaged with the rear striker E, the sliding door A is turned about an engaging point between the front latch unit D and the front striker C.In order to slide the door A which moves as mentioned above, relatively large force is required.

Accordingly, several kinds of powered sliding units for sliding the door A using the power of a motor have been conventionally proposed. These proposed sliding units are arranged to slide the door A from an open position to a completely closed position by sliding the door A in both directions of the arrow X and the arrow Y.

The conventional powered sliding units have been devised so that force for moving the door A in the directions of the arrow X and the arrow Y are efficiently transmitted to the sliding door A.

However, it is structurally difficult to increase the transmission efficiency of the force in the direction of the arrow Y. In addition, the required force for sliding the door A reaches a maximum when the rear latch unit completely engages; with the rear striker E. Accordingly, increased output power of a motor of the sliding unit is required, to achieve the above maximum force, and the size of the unit is correspondingly increased.

Accordingly, it is an object of the present invention to provide an improved latch device.

The invention provides a latch device for a vehicle sliding door attached to a vehicle body so as to be slidable in a frontand-rear direction of the vehicle body, comprising: a front latch unit attached to a front side of the sliding door for engaging with a front striker fixed to the vehicle body; a rear latch unit attached to a rear side of the sliding door for engaging with a rear striker fixed to the vehicle body, said rear latch unit having a half-latch condition in which the rear latch unit is initially engaged with the rear striker, and a full-latch condition in which the rear latch unit is completely engaged with the rear striker; a powered sliding unit provided in the vehicle body for moving the sl-iding door from an open position to a half-latch position in which the rear latch unit comes into the half-latch condition; a powered closing unit provided in the sliding door for causing the rear latch unit to displace from the half-latch condition into the full-latch condition; and a control means for controlling the powered sliding unit and the powered closing unit.

Further preferred features and advantages of the invention will become apparent from the dependent claims taken in conjunction with the following description of preferred embodiments of the invention.

The invention is illustrated by way of example in the accompanying drawings, in which: Fig. 1 is a perspective view showing a powered closing unit attached to a sliding door according to the present invention; Fig. 2 is a partly sectional view showing a relationship between the sliding door and a guide rail; Fig. 3 is a plan view of a coupling bracket of the sliding door; Fig. 4 is a sectional view of the guide rail; Fig. 5 is a partly sectional plan view showing an initial tension mechanism; Fig. 6 is a developed sectional view of Fig. 5:: Fig. 7 is a partly sectional plan view showing the initial tension mechanism in which a tension pulley is in a free condition; Fig. 8 is a partly sectional plan view showing another Fig. 8 is a partly sectional plan view showing another initial tension mechanism; Fig. 9 is a developed sectional view of Fig. 8; Fig. 10 is a partly sectioned plan view showing the initial tension mechanism of Fig. 8 in which a tension pulley is in a free condition; Fig. 11 is a partly-broken front view of a guide rail; Fig. 12 is a partly-broken front view showing a wire cable and a powered sliding unit which will be attached within an inner space inside of a rear outer side panel; Fig. 13 is an enlarged front view showing the powered sliding unit; Fig. 14 is a front view showing a clutch mechanism of the powered sliding unit in a disengaged condition;; Fig. 15 is a front view showing the clutch mechanism in an engaged condition; Fig. 16 is a front view showing the clutch mechanism from which a T-shaped swingable member is removed; Fig. 17 is a cross-sectional view showing the clutch mechanism; Fig. 18 is a partly cutaway sectional view showing a second gear and a brake shoe of a clutch member; Fig. 19 is a front view showing a final tension mechanism for the wire cable; Fig. 20 is an enlarged sectional view showing the final tension mechanism; Fig. 21 is a front view showing the powered closing unit; Fig. 22 is a longitudinal sectional view showing a rear latch unit; Fig. 23 is a rear view of the rear latch unit; Fig. 24 is an enlarged view showing a corner portion of the guide rail and the coupling bracket; and Fig. 25 is a schematic view showing a relationship between a prior art sliding door and vehicle body.

Referring to the drawings, as shown in Fig. 2, a vehicle body 2 has a sliding door 1 which is slidable in a longitudinal or front-and-rear direction of the body 2 between an open position opposite a rear outer side panel or quarter panel 3 of the body 2 powered sliding unit 6 mounted within an inner space 5 inside of the side panel 3, for sliding the door 1 The sliding door 1 and the powered sliding unit 6 are connected with each other through a wire cable 7, one half of which is located in the inner space 5, and the other half of which is fitted, as shown in Fig. 4, within a guide rail 8 secured to the side panel 3. As shown in Fig. 3, both end parts 9 of the cable 7 are coupled to a coupling bracket 10 which is rotatably attached to the door 1. Three rollers 11 of the coupling bracket 10 are slidably engaged with the guide rail 8.When the coupling bracket 10 is towed by the sliding unit 6 via the cable 7, the sliding door 1 is moved in the longitudinal direction of the body 2 along the guide rail 8.

The guide rail 8 is laid horizontally, and has at its front side part a corner portion 12 which is curved toward an interior side of the vehicle body 2. A front pulley 13 for the cable 7 is located in the vicinity of the front end part of the guide rail 8, and a rear pulley 14 for the cable 7 is located in the vicinity of the rear end part of the guide rail 8. As shown in Figs. 5 and 6, the front pulley 13 is first inserted in a holder 15 for preventing the cable 7 from coming off, then, it is attached to a bracket 17 fixed to the side panel 16. Boss portions 18 formed on the holder are fitted with a tension plate 19 to which a tension pulley 21 for applying an initial tension to the cable 7 is journalled by a vertical shaft 20.

The tension plate 19 and the tension pulley 21 are set in a free condition, as shown in Fig. 7, when the cable 7 is attached to the coupling bracket 10 and the powered sliding unit 6. After the completion of the set-up of the cable 7, the tension plate 19 is turned about the boss portions 18 by the hand toward the side panel 3, then, it is fixed to the side panel 3 by a bolt 22 and a nut 23, as shown in Fig. 5.

Figs. 8 to 10 show another type of the tension plate 19 which is slidably attached to the bracket 17.

The rear pulley 14 is journalled to the rear side panel 3 by a vertical shaft 24, and further, as shown in Fig. 12, is located at the same height as that of the front pulley 13. The powered sliding unit 6 is located between the front pulley 13 and the rear pulley 14 so that the cable 7 between the front pulley 13 and the pulley 14 so that the cable 7 between the front pulley 13 and the sliding unit 6 is substantially in parallel with the cable 7 between the sliding unit 6 and the rear pulley 14. Thus, apart from the portion within the sliding unit 6, the wire cable 7 is kept horizontal. Thereby the overall length of the cable 7 becomes shorter, and the elongation and contraction of the cable 7 due to aging can be reduced. Further, the fact that the cable 7 is laid horizontally eliminates the need for a wire sheath which surrounds the outer periphery of the cable 7.Accordingly, a bare cable 7 can be used.

As shown in Fig. 12, the powered sliding unit 6 has a substantially vertical base plate 25 fixed to the vehicle body 2, a wire drum 26 journalled to the base plate 25, a pair of counter pulleys 27, 28 journalled to the base plate 25, a pair of tension arms 29, 30 journalled to the base plate 25 by a shaft 34, and a motor 33 for rotating the wire drum 26. Tension rollers 31, 32 are rotatably attached to the tension arms 29, 30, respectively. The counter pulleys 27, 28 are located at the same height as that of the front and rear pulleys 13 and 14 so that the cable 7 in the inner space 5 is horizontal. Further, the vertical base plate 25 is substantially parallel with the cable 7 within the inner space 5.

As shown in Fig. 13, the wire drum 26 is supported from the base plate 25 by a horizontal shaft 34. A gear 35 is fixed to the wire drum 26, and a clutch mechanism 36 is arranged between the gear 35 and the motor 33.

Details of the clutch mechanism 36 are shown in Figs. 14 to 18. An output gear 38 is fixed to an output shaft 37 of the motor 33. Clutch members 39, 40 are provided on opposite sides of the output gear 38, and are supported from a T-shaped swingable member 41 by shafts 42,43. The swingable member 41 is rotatably supported from a cover plate 44 fixed to the base plate 25 by a shaft 45.

The center axis of the shaft 45 is the same as that of the output gear 37. The swingable member 41 is held at a neutral position as shown in Fig. 14 by means of the resilient force of a return spring 48 which clamps a bent portion 46 of the cover plate 44 and a bent portion 47 of the swingable member 41.

The clutch member 39 has a first gear 49 meshed with the output gear 38, and a second gear 53 meshed with an arcuate rack a first gear 50 meshed with the output gear 38, and a second gear 54 meshed with an arcuate rack 52 fixed to the base plate 25. The second gears 53, 54 make contact with the first gears 49, 50, respectively, with pred etermined frictional resistance so that one of the first gears 49, 50 and the corresponding one of the second gears 53, 54 are rotated together.

In the condition as shown in Fig. 14, when the first gears 49, 50 are rotated clockwise by the output gear 38, as indicated by the arrow, the second gears 53, 54 are also rotated clockwise due to the frictional resistances between the first gears and the second gears. As a result, due to the engagements between the second gears 53, 54 and the racks 51, 52, the swingable member 41 is turned counterclockwise as shown in Fig. 15, thereby the first gear 49 of the left side is meshed with the gear 35 of the wire drum 26. Then, the wire drum 26 is rotated counterclockwise. On the contrary, when the first gears 49, 50 and the second gears 53, 54 are rotated counterclockwise, the swingable member 41 is turned clockwise, thereby the first gear 50 of the right side is meshed with the gear 35 of the wire drum 26. Then, the wire drum 26 is therefore rotated clockwise.Further, as the motor 33 is not energized in the state shown in Fig. 15, the swingable member 41 is returned to the neutral position by the resilient force of the return spring 48, and thereby the coupling between the motor 33 and the wire drum 26 is released.

The frictional resistances between the first gear 49 and the second gear 53 and between the first gear 50 and the second gear 54 are caused by springs 55, 56 and brake shoes 57, 58, respectively. The springs 55, 56 are respectively arranged between end edges 59, 60 of the second gears 53, 54 and brake shoes 57, 58 so that the brake shoes 57, 58 are biased toward boss portions 61, 62 of the first gears 49, 50, respectively.

Figs. 19 and 20 show a tension adjusting mechanism for the wire cable 7. The adjusting mechanism is adapted to carry out the final adjustment of the tension pressure of the cable 7 to which the initial tension is already applied by the tension pulley 21 shown in Figs. 5 to 9. The tension adjusting mechanism has a pair of adjusting plates 63, 64 which are rotatably attached to the shaft 34. A tension spring 65 is connected with the adjusting plates 63 and 64.

The tension adjusting mechanism further has a pair of adjusting members 66, 67 which are rotatably and slidably attached to pins 70, 71 of brackets 68, 69 fixed to the arms 29, 30, respectively. A plurality of protrusions 72, 73 of the adjusting members 66, 67 are engaged in a plurality of holes 76, 77 formed in the arms 29, 30 by the resilient forces of springs 74, 75, respectively. Gear portions 80, 81 formed on the adjusting members 66, 67 are meshed with arcuate gear portions 78, 79 of the adjusting plates 63, 64.

The left tension arm 29 and the left adjusting plate 63 are integrally coupled with each other through the engagement between the gear part 78 and the gear part 80, and the right tension arm 30 and the right adjusting plate 64 are integrally coupled with each other through the engagement between the gear part 79 and the gear part 81. Accordingly, the arms 29, 30 are urged by the resilient force of the tension spring 65 in the direction in which the wire cable 7 is tensed.

The adjusting members 66, 67 have grooves 83, 84 in which a driver 82 is engagable. By turning the adjusting members 66, 67 using the driver 82, the angle between the tension arm 29 and the adjusting plate 63 and the angle between the tension arm 30 and the adjusting plate 64 can be independently adjusted.

When the initial tension is applied to the cable 7 by the tension pulley 21, the cable 7 causes the tension arms 29, 30 to turn against the resilient force of the tension spring 65. At this time, if a manufacturing error in the length of the cable 7 has occurred, the length of the stretched spring 65 is not within allowed tolerances. If the length of the stretched spring 65 is longer than the designed length due to the shorter length of the cable 7, the tension pressure becomes larger. On the contrary, if the length of the stretched spring 65 is shorter due to the longer length of the cable 7, the tension pressure becomes less. In these cases, the angle between the tension arm 29 and the adjusting plate 63 and the angle between the tension arm 30 and the adjusting plate 64 are changed by turning both adjusting members 66, 67 using the driver 82 so as to adjust the length of the stretched spring 65 to the designed length after the initial tension is applied to the cable 7 by the tension pulley 21. Accordingly, in the present invention even though a manufacturing error may occur in the length of the cable 7, a desired tension pressure can be applied to the cable 7.

The horizontal thickness of the powered sliding unit 6 is thinner than that of a conventional one. Since, in the conventional powered sliding unit, a wire drum is attached to a horizontal base plate using a vertical shaft, the horizontal thickness of the sliding unit is larger than the diameter of the wire drum. However, according to this embodiment of the present invention, the wire drum 26 of the sliding unit 6 is attached to the vertical base plate 25 by the horizontal shaft 34, and therefore, the horizontal thickness of the sliding unit 6 can be set to be substantially equal to the thickness of the wire drum 26.

Further, since the thickness of the wire drum 26 can be easily decreased by increasing the diameter of the wire drum 26, the horizontal thickness of the sliding unit 6 can be easily decreased.

Thus, the sliding unit 6 of the present embodiment can easily be stored in the inner space 5 inside of the side panel 3.

Referring again to Fig. 1, the sliding door 1 has a front latch unit 86 adapted to be engaged with a front striker 85 fixed to the vehicle body 2, and a front latch unit 88 adapted to be engaged with a rear striker 87 fixed to the vehicle body 2. When the sliding door 1 is slid toward the closed position, the front latch unit 86 is at first engaged with the front striker 85, and thereafter, the rear latch unit 88 is engaged with the rear striker 87. The engagement between the rear latch unit 88 and the rear striker 87 includes two kinds of engagement, that is, a half-latch engagement as an initial engagement and a full-latch engagement as a complete engagement. The sliding of the door 1 toward the closed position by the sliding unit 6 is continued until the half-latch engagement is attained.

The slide door 1 has a powered closing unit 89 for achieving the full-latch engagement, and a connector 91 connected to the powered closing unit 89 through an electric cable 90. A connector 92 is provided on the vehicle body 2 and connected to a battery 93.

By the sliding of the door 1 toward the closed position, the connector 91 of the door 1 makes contact with the connector 92 of the body 2 before the rear latch unit 88 is initially engaged with the rear striker 87, and then, the powered closing unit 89 is supplied with the electric power from the battery 93.

A control unit 200 for controlling the powered sliding unit 6 and the powered closing unit 89 is provided in the vehicle body 2. The control unit 200 is connected to the rear latch unit 88 through a plurality of signal cables 94.

Between the powered closing unit 89 and the rear latch unit 88, a wire cable 89 for transmitting the power from the closing unit 89 to the rear latch unit 88 is provided. When the control unit 200 receives a half-latch signal from the rear latch unit 88 through the signal cables 94, it actuates the powered closing unit 89 so as to draw the wire cable 95, thereby the condition of the rear latch unit 88 is displaced into the full-latch condition from the half-latch condition.

Referring to Fig. 21 which shows the powered closing unit 89 in detail, a motor 97 is secured to a base plate 96 of the closing unit 89. A sector gear 99 is meshed with an output gear 98 of the motor 97 and is journalled to the base plate 96 by a shaft 100.

A winch lever 101 to which one end of the wire cable 95 is engaged is rotatably journalled to the shaft 100. A coupling lever 102 is provided between the winch lever 101 and the sector gear 99. The coupling lever 102 has formed therein an elongated hole 103 into which the shaft 100 is inserted, and accordingly, the coupling lever 102 can be slid by a degree corresponding to the play between the elongated hole 103 and the shaft 100.

The coupling lever 102 is provided at its one end with a pair of pin portions 104 projected toward both sides of the lever 102.

One of the pin portions 104 is engaged with a U-shaped recess 105 of the sector gear 99, and the other of the pin portions 104 is engaged in an elongated hole 106 of the winch lever 101. The coupling lever 102 is biased by the resilient force of a spring 107 so that the engagement between the pin portion 104 and the recess 105 is maintained.

When the rear latch unit 88 comes to the half-latch condition, the motor 97 of the closing unit 89 begins to rotate.

Then, the sector gear 99 is turned counterclockwise as viewed in Fig. 21 and the winch lever 101 is also turned counterclockwise so as to draw the wire cable 95 since the pin portions 104 are engaged with both the U-shaped recess 105 and the elongated hole 106.

Thereby, the power of the closing unit 89 is transmitted to the rear latch unit 88 and the condition of the latch unit 88 is displaced into the full-latch condition. Thus, according to the present invention, the sliding door 1 in the open condition is slid under the power of the sliding unit 6 until it comes to the halflatch condition, and thereafter, it comes to the full-latch condition under the power of the closing unit 89. Accordingly, in order to close the door 1 the driver is only required to turn on an operating switch.

A cancelling lever 108 for shutting off a power transmission path between the motor 97 and the rear latch unit 88 is rotatably mounted on the base plate 96. The cancelling lever 108 is coupled to an open lever 110 adapted be turned by an outer open handle or an inner open handle 109 of the door 1. When the cancelling lever 108 is turned by the open handle 109 through the intermediary of the open lever 110 during rotation of the sector gear 99 by the motor 97, the cancelling lever 108 is engaged with a tip end of the coupling lever 102. Then, the lever 102 slides against the resilient force of the spring 107 so as to reIease the pin portion 104 from the U-shaped recess 105 of the sector gear 99. Therefore, the power transmission path between the motor 97 and the rear latch unit 88 is shut off.This cancelling manipulation is carried out if the operator catches his hand, clothes, bag or the like in the door 1.

Referring to Figs. 22 and 23 which show the rear latch unit 88, a latch 112 adapted to be engaged with the rear striker 87 and a ratchet 113 adapted to be engaged with the latch 112 so as to maintain the engagement between the latch 112 and the striker 87 are stored in a latch body 111 of the rear latch unit 88. The ratchet 113 is engaged with a half-latch step portion 114 of the latch 112 when the latch 112 is turned to the half-latch condition or position due to the engagement between the latch 112 and the striker 87.

A latch shaft 115 for supporting the latch 112, has fixed thereto a switch lever 116, as shown in Fig. 23, which is turned together with the latch 112. When the latch 112 comes to the halflatch position, the switch lever 116 makes contact with a terminal arm 118 of a switch 117. Accordingly, the switch 117 sends a halflatch signal to the control unit 200 through the signal cables 94.

A cable lever 120 is journalled to the latch body 111 by a shaft 119. One end of the wire cable 95 is engaged with the cable lever 120. A rotating arm 121 is fixed to the shaft 119 so as to be rotated together with the cable lever 120. A link 123 having a roller 122 is rotatably connected to the rotating arm 121. The roller 122 is moved along a guide groove 124 formed in the latch body 111 when the cable lever 120 is turned by the force of the powered closing unit 89.

The latch 112 is provided with a leg portion 125 which overlaps with the guide groove 124 when in the half-latch position.

When the latch 112 comes to the half-latch position, the roller 122 moves along the guide groove 124 by the power of the closing unit 89 and makes contact with the leg portion 125 of the latch 112. Thereby the latch 112 is turned to the full-latch position from the half-latch position. Then, the ratchet 113 is engaged with a full-latch step portion 126 of the latch 112. When the latch comes to the full-latch position, the switch lever 116 comes away from the terminal arm 118, and accordingly, the switch 117 sends a full-latch signal to the control unit 200 through the signal cables 94.

A ratchet lever 128 coupled to the ratchet 113 by a pin 127 is journalled to the latch body 111. An intermediate lever 129 adapted to be turned by the open handle 109 is provided in the vicinity of the ratchet lever 128. When the intermediate lever 129 is rotated by the opening operation of the open handle 109, it engages with the ratchet lever 128 so as to release the ratchet 113 from the latch 112. Then, the door 1 is open.

Referring again Fig. 1, it should be noted that the wire cable 7 makes contact with the corner portion 12 of the guide rail 8 under high pressure. This contact can cause abrasion of the cable 7 and the guide rail 8. Therefore, as shown in Fig. 24, a roller 130 is rotatably attached to the corner portion 12 of the guide rail 8. The roller 130 is preferably urged in the direction of the arrow by the resilient force of a spring 131.

The roller 130 provided to the corner portion 12, has another role. As shown in Fig. 24, the end parts 9 of the cable 7 coupled to the coupling bracket 10 are separated from the guide rail 8.

In such a condition, the distance between the end parts 9 and the wire drum 26 differs at the time when the coupling bracket 10 is positioned in a straight portion of the guide rail 8 from the time when the coupling bracket 10 is positioned in the corner portion 12 of the guide rail 8, and accordingly, the tension in the cable 7 varies. However, the roller 130 is provided at the corner portion 12, and accordingly, the difference in the distance between the end part 9 and the wire drum 26 is decreased, thereby it is possible to reduce variation in tension in the cable 7.

Claims

1. A latch device for a vehicle sliding door attached to a vehicle body so as to be slidable in a front-and-rear direction of the vehicle body, comprising: a front latch unit attached to a front side of the sliding door for engaging with a front striker fixed to the vehicle body; a rear latch unit attached to a rear side of the sliding door for engaging with a rear striker fixed to the vehicle body, said rear latch unit having a half-latch condition in which the rear latch unit is initially engaged with the rear striker, and a full-latch condition in which the rear latch unit is completely engaged with the rear striker; a powered sliding unit provided in the vehicle body for moving the sliding door from an open position to a half-latch position in which the rear latch unit comes into the half-latch condition; a powered closing unit provided in the sliding door for causing the rear latch unit to displace from the half-latch condition into the fulllatch condition; and a control means for controlling the powered sliding unit and the powered closing unit.

2. A latch device as claimed in claim 1, wherein said rear latch unit comprises a switch for sending a half-latch signal to the control means when the rear latch unit comes into the half latch condition, and wherein said control means is arranged to actuate the powered closing unit when the control means receives the half-latch signal.

3. A latch device as claimed in claim 1 or 2, wherein said rear latch unit further comprises a latch for engaging with the rear striker, a ratchet for holding the latch in the half-latch condition or the full-latch condition, and a closlng means for displacing the latch from the half-latch condition into the fulllatch condition under the power of the powered closing unit.

4. A latch device as claimed in any one of claims 1-3, wherein said vehicle body has a first connector connected to a battery on the vehicle body, wherein said sliding door has a second connector connected to the powered closing unit through an electrical cable, and wherein said first connector and said second connecter make contact with each other before the rear latch unit comes into the half-latch condition during the closing of the sliding door.

5. A latch device as claimed in any one of claims 1-4, wherein said powered sliding unit comprises a motor, a wire drum rotated by the motor, and a wire cable for coupling the wire drum with the sliding door, and wherein said vehicle body has on a rear outer side panel thereof a horizontal guide rail extending in the front-and rear direction of the vehicle body.

6. A latch device as claimed in claim 5, wherein said powered sliding unit has a vertical base plate to which the wire drum is rotatably attached by a horizontal shaft, and wherein said powered sliding unit is attached in an inner space inside of the rear outer side panel.

7. A latch device as claimed in claim 5, wherein approximately half of said wire cable is laid within the guide rail and the remainder is laid within an inner space inside of the rear outer side panel, and wherein said remainder of said wire cable, except a portion within the powered sliding unit, is arranged to extend horizontally.

8. A latch device as claimed in any one of claims 5-7, wherein said wire cable is not surrounded by a wire sheath.

9. A latch device as claimed in any one of claims 5-8, wherein said vehicle body has a front pulley positioned in the vicinity of a front end part of the guide rail for engaging the wire cable and a rear pulley positioned in the vicinity of a rear end part of the guide rail for engaging the wire cable, and wherein said front pulley and said rear pulley are arranged at the same height.

10. A latch device as claimed in any one of claims 5-8, wherein said vehicle body has a front pulley positioned in the vicinity of a front end part of the guide rail for engaging the wire cable, a rear pulley positioned in the vicinity of a rear end part of the guide rail for engaging the wire cable, and a tension pulley provided between the front pulley and the rear pulley for applying an initial tension to the wire cable, and wherein said tension pulley is fixed to the rear outer side panel by means of a fastener such as a bolt or a screw after the tension pulley is moved substantially orthogonal to the wire cable.

11. A latch device as claimed in claim 10, wherein said tension pulley is rotatably journalled by a first shaft to a swingable tension plate which is rotatably journalled to a bracket secured to the rear outer side panel by a second shaft.

12. A latch device as claimed in claim 11, wherein said front pulley is rotatably attached to the bracket by a third shaft.

13. A latch device as claimed in any one of claims 10-12, wherein said tension pulley is slidably attached to a bracket fixed to the rear outer side panel.

14. A latch device as claimed in any one of claims 5-13, wherein said powered sliding unit further comprises a vertical base plate to which the motor and the wire drum are attached, and a pair of counter pulleys journalled to the base plate by horizontal shafts, wherein said wire drum is located between the counter pulleys, and wherein said counter pulleys are provided at the same height as that of the guide rail.

15. A latch device as claimed in claim 14, wherein said wire drum is rotatably journalled to the base plate by a horizontal shaft, and wherein said powered sliding unit is attached in an inner space inside of the rear outer side panel.

16. A latch device as claimed in any one of claims 5-15, wherein said guide rail has in a front portion thereof a corner portion curved toward an interior side of the vehicle body, and a corner roller provided in the corner portion for making contact with the wire cable.

17. A latch device as claimed in claim 16, wherein said corner roller is urged by a resilient force of a spring in a direction orthogonal to the corner portion.

18 A latch device as claimed in claim 1 and substantially as described herein with reference to the accompanying drawings.