Power device for opening and closing a vehicle sliding door

A clutch mechanism of the power device includes a movable gear member which is rotated integrally with a wheel and engaged with a stationary gear member when moved in a first direction and disengaged from the stationary gear member when moved in a second direction opposite to the first direction, an armature which moves the movable gear member in the first direction when rotated relatively to the movable gear member, and an electromagnetic coil for applying brake resistance to the armature by attracting the armature by magnetic force to restrict a co-rotating state of the armature and the movable gear member. The armature has a clutch holding surface for maintaining a clutch-engaged state where the movable gear member and the stationary gear member are engaged with each other even when the electromagnetic coil is turned off in the clutch-engaged state.

FIELD OF THE INVENTION

The present invention relates to a power device and more particularly to a power device which slides a sliding door in a door-opening direction and a door-closing direction.

DESCRIPTION OF THE RELATED ART

A conventional vehicle sliding door may be equipped with power devices such as a power slide device for sliding the sliding door in the door-opening direction and the door-closing direction by motor power, a power close device for moving the sliding door from a half-latched position to a full-latched position by motor power and a power release device for unlatching a door latch device of the sliding door by motor power.

The power device, particularly the power device used as a power slide device, is equipped with a clutch mechanism for transmitting motor power to the sliding door. The clutch mechanism is classified broadly into a mechanical clutch mechanism and an electromagnetic clutch mechanism, and they have advantages and disadvantages, respectively.

The mechanical clutch mechanism has an advantage that it includes few electrical components and thus can be manufactured with low cost. However, the mechanical clutch mechanism involves a time lag in switching the clutch from the disengaged state to the engaged state or vice versa. This time lag complicates control programs for mechanical clutch mechanism.

On the contrary, with electromagnetic clutch mechanism, switching from the disengaged state to the engaged state or vice versa can be rapidly achieved. Thus, its control programs can be dramatically simplified. However, electromagnetic clutch device applicable to a high-output power device such as a power slide device have a disadvantage that it requires a large, high cost electromagnetic coil.

There will be described the reason that a large electromagnetic coil is required. There are some kinds of electromagnetic clutch mechanisms which are broadly classified into a frictional clutch and a dog clutch. The frictional clutch is connected by causing an armature to come into contact with a frictional rotary plate by the magnetic force of the electromagnetic coil. The magnitude of the output which can be transmitted by the clutch depends on the magnitude of a friction coefficient between the armature and the rotary plate. Therefore, a high-output power device such as a power slide device requires a high-power electromagnetic coil for providing a large friction coefficient.

In contrast, the dog clutch is connected by causing a rugged portion of an armature to mesh with a rugged portion of a rotary plate. In the mesh executed between the rugged portions, the magnitude of a force for pressing the armature against the rotary plate does not substantially affect the magnitude of output that can be transmitted by the clutch. In the dog clutch, however, the moving distance of the armature, which is required for the armature to be meshed with the rotary plate is greatly longer than that of the armature required in the frictional clutch. The typical moving distance of the armature of the frictional clutch is 1 mm or less, so that it can be moved by the small magnetic force of a compact electromagnetic coil. However, in the dog clutch, the armature must be typically moved by a distance of 3 to 5 mm. The magnetic force drastically decreases as the distance increases, so that the electromagnetic coil must be large in order to move the armature of dog clutch.

In order to overcome the problems, the present inventor has suggested a power device including a clutch mechanism using a combination of a mechanical clutch mechanism and an electromagnetic clutch mechanism (U.S. patent application Ser. No. 10/611,642).

With the configuration of the previously-filed application, when the electromagnetic coil is turned off, this causes the clutch mechanism to return from the engaged state to the disengaged state. Therefore, this configuration has problems in terms of operability and usability.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide a power device including a clutch mechanism capable of maintaining the engaged state of the clutch even if the electromagnetic coil is turned off.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will be described with reference to the drawings.FIG. 2shows a vehicle body10, a sliding door11which is slidably mounted to the vehicle body10, and a door ingress/egress aperture12which can be closed by the sliding door11. An upper rail13is secured to the vehicle body10in the vicinity of an the upper portion of the door aperture12, a lower rail14is secured to the vehicle body10in the vicinity of an lower portion of the door aperture12, and a center rail16is secured to a quarter panel15which is a rear side surface of the vehicle body10. The sliding door11is provided with an upper bracket17which is slidably engaged with the upper rail13, a lower bracket18which is slidably engaged with the lower rail14, and a center bracket19which is slidably engaged with the center rail16. Preferably, each bracket17,18,19is rotatably mounted to the sliding door11and the sliding door11is slidable in the door-opening direction and in the door-closing direction by the engagement between these brackets and these rails.

A power unit20with motor power is provided within the inner space50(FIG. 2) of the sliding door11. The power unit20includes a wire drum30, as shown inFIGS. 6 and 7, for winding and paying out two wire cables, namely a door-opening cable21′ and a door-closing cable21″, base ends of which are connected to the wire drum30. When the wire drum30rotates in the door-opening direction, the door-opening cable21′ is wound and the door-closing cable21″ is paid out, and when the wire drum30rotates in the door-closing direction, the door-opening cable21′ is paid out and the door-closing cable21″ is wound.

As shown inFIG. 4, the door-opening cable21′ is drawn out from a front lower position of the sliding door11, namely a position in the vicinity of the lower bracket18, toward the vehicle body (toward the lower bracket18) to the outside of the sliding door11. The lower bracket18is provided with a pulley22having a vertical axial center, and the door-opening cable21′ which is paid out from the sliding door11passes by the front side of the pulley22, then extends rearward through the lower rail14, and is secured to the rear end portion of the lower rail14or to the vehicle body10in the vicinity of the rear end portion. Thus, when the door-opening cable21′ is wound in the state where the door is closed, the sliding door11slides rearward (in the door-opening direction) through the lower bracket18.

As shown inFIG. 5, the door-closing cable21″ is drawn out from a central position in an up-and-down direction of the sliding door11on the rear side thereof, i.e. from a position in the vicinity of the center bracket19toward the vehicle body (toward the center bracket19) to the outside of the sliding door11. The center bracket19is provided with a pulley23having a vertical axial center, and the door-closing cable21″ which is paid out from the sliding door11passes by the rear side of the pulley23, then extends forward through the center rail16, and is secured to the front end portion of the center rail16or to the vehicle body10in the vicinity of the front end portion. Thus, when the door-closing cable21″ is wound in the state where the door is opened, the sliding door11slides forward (in the door-closing direction) through the center bracket19.

Referring toFIGS. 6 and 7, a cylindrical worm25is mounted to an output shaft of a high-power motor24, and a first worm wheel26and a second worm wheel27are provided on both the sides of the axial center of the cylindrical worm25such that they are meshed with the cylindrical worm25, respectively. The first worm wheel26is pivotally mounted on a first supporting shaft28within a case29of the power unit20, and the wire drum30is also pivotally mounted on the first supporting shaft28. A first clutch31is provided between the first worm wheel26and the wire drum30. When the first clutch31is turned on, the rotation of the first worm wheel26is transmitted to the wire drum30, and when the first clutch31is turned off, the wire drum30becomes free with respect to the first worm wheel26. Therefore, inFIG. 6, if the first clutch31is turned on while the first worm wheel26is being rotated in the clockwise direction by the normal rotation of the motor24, the wire drum30is also rotated clockwise, thereby the door-opening cable21′ is paid out and the door-closing cable21″ is wound. On the contrary, if the first clutch31is turned on while the first worm wheel26is being rotated counterclockwise by the reverse rotation of the motor24, the wire drum30is also rotated counterclockwise, thereby the door-opening cable21′ is wound and the door-closing cable21″ is paid out. This function of rotating the wire drum30through the power of the motor24for winding and paying out the cables21′,21″ is the power sliding function of the power unit20.

The cylindrical worm25and the first worm wheel26are related to each other such that any rotational force applied to the first worm wheel26does not cause the cylindrical worm25to rotate.

The second worm wheel27is pivotally mounted on a second supporting shaft32within the case29of the power unit20. One end portion of the second supporting shaft32penetrates the case29and protrudes to the outside of the case, and a swing arm33is secured to the protruded portion of the second shaft. A second clutch34is provided between the second worm wheel27and the second supporting shaft32. When the second clutch34is turned on, the rotation of the second worm wheel27is transmitted to the swing arm33through the second supporting shaft32, and when the second clutch34is turned off, the swing arm33becomes free with respect to the second worm wheel27.

One end of a release cable35is connected to a tipe end of the swing arm33. The other end of the release cable35is coupled to a door latch unit36(FIGS. 1 and 8) of the sliding door11. When the release cable35is pulled in the direction of an arrow A by swinging the swing arm33, the door latch unit36is released. An example of the door latch unit36is shown inFIG. 8and the door latch unit36includes a latch38engageable with a striker37(FIG. 1) secured to the vehicle body10and a ratchet39engageable with the latch38. The latch38is urged in the clockwise direction by the elasticity of a latch spring40, and the ratchet39is urged by the elasticity of a ratchet spring41in the counterclockwise direction. When the sliding door11is moved in the door-closing direction, the latch38is brought into contact with the striker37and is rotated from a door-open position (an unlatched position) shown by a solid line through a half-latched position where the ratchet39is engageable with a half-latched step42of the latch38to a full-latched position (the position shown by a dotted line) where the ratchet39is engageable with a full-latched step43of the latch38, and when the ratchet39is engaged with the full-latched step43, the closing of the sliding door11is completed. The release cable35is operatively connected to the ratchet39, and when the release cable35is pulled in the direction of the arrow A the ratchet39is disengaged from the latch38to unlatch the door latch unit36, thereby the sliding door11is placed in an openable state. The function of swing the swing arm33through the power of the motor24for unlatching the door latch unit36is the power releasing function of the power unit20.

The first clutch31, which is shown inFIG. 7in detail, is a clutch which is turned on and off by electrical control. Basically, when an electromagnetic coil60is turned on, the clutch is engaged, and when the electromagnetic coil60is turned off, the clutch is disengaged. The electromagnetic coil60has a cylindrical shape and is disposed around the first supporting shaft28. The electromagnetic coil60is fixed relatively to the case29, and the first supporting shaft28is rotatable relatively to the electromagnetic coil60. The first worm wheel26is rotatably supported around the outer circumference of the electromagnetic coil60. An annular armature61is disposed on the left side of the electromagnetic coil60in the vicinity of thereof. The armature61is rotatably mounted on the first supporting shaft28and is movably in the axial direction of the shaft28. The armature61is urged leftward by the week elasticity of a spring62so as to separate from the electromagnetic coil60and is abutted against a step of the first supporting shaft28. When the electromagnetic coil60is turned on, the right surface of the armature61is caused to come into intimate contact with the left surface of the electromagnetic coil60by the magnetic force of the electromagnetic coil60. The frictional resistance generated by this intimate contact acts as a brake resistance required for the clutch engagement. Since the brake resistance required for the clutch engagement is little and the armature61can be placed in the vicinity of the electromagnetic coil60, the electromagnetic coil60is required to generate only little magnetic force, thereby allowing the use of a lightweight, compact and low-cost electromagnetic coil.

A cam member63is secured on the left surface of the armature61. A cam surface64of the cam member63is formed into an annular and regular rugged surface, as shown inFIG. 9, having apexes64A bulged leftward in the axial direction of the first supporting shaft28, bottom portions64B formed by cutting-out, and slant surfaces64C for connecting them. The slant surface64C is a two-step slant surface having a clutch holding surface64D in the middle thereof. The clutch holding surface64D at the middle position is a configuration constituting the main feature of the present invention. As will be described later, the clutch holding surface64D maintains the clutch in the engaged state even when the electromagnetic coil60is turned off. As shown inFIG. 11, the slant surface64C is a slant surface at an angle of preferably about 30 degree with respect to right angle to the axial line X of the first supporting shaft28, and the clutch holding surface64D may be flat surface orthogonal to the axial line X. However, the clutch holding surface64D is preferably formed as a sweepback surface at an angle of about 10 degree.

A movable gear member65(FIG. 10) is provided at the left of the cam member63. The movable gear member65is rotatably mounted on the first supporting shaft28rotatably and movably in the axial direction of the shaft. A plurality of leg portions66extending rightward are formed on the outer periphery of the movable gear member65. The right tip ends of the leg portions66are engaged with engaging grooves67of the first worm wheel26so that the movable gear member65is rotated by the rotation of the first worm wheel26in association therewith. The leg portions66are slidable with respect to the engaging grooves67in the axial direction of the first supporting shaft28, but the leg portions66are disengageable from the engaging grooves67even if the movable gear member65is moved in the axial direction of the first supporting shaft28. Therefore, the movable gear member65is always rotated together with the first worm wheel26. On the left surface of the movable gear member65, a movable annular gear portion68centered on the first supporting shaft28is formed.

A stationary gear member69is disposed at the left side of the movable gear member65, and a spring70for pushing out the movable gear member65rightward is provided between the movable gear member65and the stationary gear member69. The left surface of the stationary gear member69is secured to the wire drum30and they rotate integrally. The wire drum30is secured to the left side of the first supporting shaft28such that the wire drum30rotates integrally with the first supporting shaft28. A stationary annular gear portion71is provided on the right surface of the stationary gear member69. When the movable gear member65slides leftward against the elasticity of the spring70.with respect to the first supporting shaft28, the movable annular gear portion68meshes with the stationary annular gear portion71, and then the clutch-engaged state is accomplished. Thus the rotation of the first worm wheel26can be transmitted to the wire drum30. On the contrary, when the movable gear member65is slid rightward by the elasticity of the spring70with respect to the first supporting shaft28, the movable annular gear portion68is separated from the stationary annular gear portion71, and then the clutch becomes the clutch-disengaged state. Thus the rotation of the first worm wheel26is no longer transmitted to the wire drum30.

The movable gear member65has a cam surface72for sliding the movable gear member65leftward against the elasticity of the spring70in cooperation with the cam surface64of the cam member63. The cam surface72is an annular and regular rugged surface having apexes72A bulged rightward in the axial direction of the first supporting shaft28, bottom portions72B, and slant surfaces72C for connecting them. The cam surface72has a symmetric structure with respect to the cam surface64, but include no clutch holding surface. However, by forming the clutch holding surfaces64D on any one of the cam surface64and the cam surface72, desired effects can be obtained.

When the movable gear member65is slid rightward by the elasticity of the spring70, as shown inFIG. 12, the apexes72A of the cam surface72usually closely conform to the bottom portions64B of the cam surface64, and the movable annular gear portion68is separated from the stationary annular gear portion71as in the schematic view ofFIG. 13, thereby the clutch is held in the disengaged state. In this clutch-disengaged state, when the electromagnetic coil60is turned on, the right surface of the armature61is attracted towards the left surface (frictional surface) of the electromagnetic coil60by the magnetic force and is brought into intimate contact therewith and thus the break resistance is applied to the armature61and the cam member63. Then, when the movable gear member65(the cam surface72) is rotated by the power of the motor24, the cam surface72and the cam surface64of the cam member63are shifted in phase from each other as shown inFIG. 14since the rotation of the cam member63is restricted, and the movable gear member65is pushed out leftward against the elasticity of the spring70. Thus, as shown inFIG. 15, the movable annular gear portion68is engaged with the stationary annular gear portion71to cause the clutch to be engaged.

When the motor24and the electromagnetic coil60are both turned off in the clutch-engaged state shown inFIGS. 14,15, the movable gear member65moves rightward by the elasticity of the spring70while causing the armature61and the cam member63released from the break resistance to rotate in the relief direction. Then, before the movable gear member65and the stationary gear member69are disengaged from each other, the apexes72A of the movable gear member65abut on the clutch holding surfaces64D as shown inFIGS. 16 and 17, which restricts the rightward movement of the movable gear member65caused by the elasticity of the spring70. In this state, the abutment between the apexes72A and the clutch holding surfaces64D can not be released unless the armature61and the cam member63are moved downward inFIG. 16or the movable gear member65is moved upward inFIG. 16. However, the armature61and the cam member63can not be moved downward and also the movable gear member65can not be moved since it engages with the first worm wheel26. Therefore, even when the electromagnetic coil60is in the OFF state, the clutch-engaged state can be maintained. Further, by causing this state on purpose, for example, in the power slide device as the present embodiment, the sliding door11can be retained at a desired position by the resistance force of the reduction gear in the motor24side.

The second clutch34has the same configuration as that of the first clutch31, and has a cylindrical electromagnetic coil73, an annular armature74, a spring75, a cam member76, a cam surface77of the cam member76, a movable gear member78, leg portions79, engaging grooves80, a movable annular gear portion81, a stationary gear member82, a spring83, a stationary annular gear portion84, and a cam surface85of the movable gear member78. The stationary gear member82of the second clutch34is secured to a receiving member86secured to the left end of the second supporting shaft32.

InFIG. 8, the sliding door11has a power close device44attached to the inside thereof. The motor power from the power close device44is transmitted to the latch38of the door latch unit36through a close cable45. In the shown embodiment, the power close device44is arranged as a device independent of the power unit20. When the latch38is displaced into the half-latched position by the movement of the sliding door11in the door-closing direction, the power close device44pulls the close cable45to cause the latch38to rotate from the half-latched position to the full-latched position, thereby the sliding door11is completely closed.

InFIG. 7, one end of the first supporting shaft28penetrates the case29and protrudes to the outside, and a gear51is secured to the protruded end of the shaft. The gear51is engaged with a rotary member52. When the rotation of the wire drum30causes the first supporting shaft28to rotate, the rotary member52rotates in conjunction therewith. Reference numeral53is a control board of the power unit20, and a sensor54for detecting the rotation (and the direction of rotation, the speed of rotation) of the rotary member52is directly mounted on the control board53. In a preferred embodiment of the rotary member52, S-pole magnetic materials and N-pole magnetic materials are disposed on the rotary member circumferentially at intervals, and the sensor54is a Hall IC for detecting magnetism. By mounting the sensor54directly on the control board53, no harness is required, which produces effects against electrical noises from the outside.

The power unit20shown inFIGS. 6 and 7has a power sliding function and a power releasing function, and both the functions share the single motor24.

The effects of the first clutch31will be explained. When the electromagnetic coil60is in the OFF state, there is no substantial frictional resistance generated between the armature61and the electromagnetic coil60. In this state, when the cylindrical worm25is rotated by the normal rotation of the motor24, the first worm wheel26is rotated in the clockwise direction inFIG. 6, and the movable gear member65is also rotated in the clockwise direction by the engagement between the leg portions66and the engaging grooves67. At this time, the movable gear member65is moved rightward by the elasticity of the spring70and the movable gear portion68of the movable gear member65is, as shown inFIG. 7, separated from the stationary gear portion71of the stationary gear member69(This is the clutch-disengaged state.). Further, as shown inFIGS. 12 and 13, the cam surface72of the movable gear member65comes into contact with the cam surface64of the cam member63in adjacent to each other. Therefore, in this state, the normal rotation of the motor24causes the movable gear member65, the cam member63and the armature61integral with the cam member63rotate together.

In the above state, when the electromagnetic coil60is turned on, the armature61is attracted towards the electromagnetic coil60by the generated magnetic force and predetermined break resistance is generated between the electromagnetic coil60and the armature61. This restricts the co-rotation of the armature61and the cam member63, and the movable gear member65is rotated about the first supporting shaft28with respect to the cam member63. Then, the cam surface72and the cam surface64are shifted in phase from each other as shown inFIG. 14, and the movable gear member65is pushed out towards the stationary gear member69, thereby the movable annular gear portion68of the movable gear member65is engaged with the stationary gear portion71of the stationary gear member69to cause the clutch-engaged state. Thus, the rotation of the motor24is transmitted to the wire drum30through the stationary gear member69, and the door-closing cable21″ is wound, thereby moving the sliding door11in the door-closing direction. After the accomplishment of the clutch-engaged state, the armature61and the cam member63rotate together with the movable gear member65.

During the movement of the sliding door11in the door-closing direction, if the motor24and the electromagnetic coil60are turned off, the movable gear member65begins to move rightward by the elasticity of the spring70even though the movable gear member65does not rotate since it engages with the first worm wheel26. The rightward movement of the gear member65causes the armature61and the cam member63to rotate in the relief direction (the downward direction inFIG. 15). Then, before the movable gear member65is disengaged from the stationary gear member69, as shown inFIGS. 16 and 17, the apexes72A of the movable gear member65are brought into contact with the clutch holding surfaces64D, thereby the further rightward movement of the movable gear member65by the elasticity of the spring70is restricted. At this state, the abutment between the apexes72A and the clutch holding surfaces64D can not be released unless the armature61and the cam member63are moved downward inFIG. 16or the movable gear member65is moved upward inFIG. 16. However, the armature61and the cam member63can not be moved downward and also the movable gear member65can not be moved since gear member65engages with the first worm wheel26. Therefore, even when the electromagnetic coil60is in the OFF state, the clutch-engaged state can be maintained. Therefore, the sliding door11is maintained at the position where the motor24and the electromagnetic coil60are turned off. With this function, the sliding door11can be stopped and retained at an arbitrary position by operator's purpose and also can be stopped and retained at a state where the sliding door is half-opened (or half-closed) by automatic operation through the control section.

When the sliding door11has been closed, the motor24is rotated in the opposite direction for a predetermined time (by a predetermined amount). Then, since the electromagnetic coil60is continuously in the ON state, the movable gear member65moves upward inFIG. 15by a predetermined amount while the armature61and the cam member63are retained. Thus, as shown inFIGS. 18 and 19, the apexes72A are moved beyond the clutch holding surfaces64D of the cam member63, and the electromagnetic coil60and the motor24are then turned off. As a result, the movable gear member65can be moved rightward by the elasticity of the spring70without causing the apexes72A to abut on the clutch holding surfaces64D of the cam member63.

(Effect of the Invention)

In the present invention, even when the electromagnetic coil60is turned off, the clutch can be continuously maintained at the engaged state. Therefore, for example, in the case where the power device of the present invention is used in a power slide device, since a sliding door which is a member to be driven can be maintained to be coupled to the reduction gear of the motor24, the sliding door can be retained at a desired position by the large resistance force of the reduction gear. Further, the clutch-engaged state can be maintained without causing power consumption.