Abstract:
In the starting clutch, an electrical pump or an engine pump is omitted and a substitutive pump mechanism is obtained with a simple construction thereby to circulate lubricating oil within the starting clutch. There is provided a starting clutch in which lubricating oil supplied form a drive shaft side is circulated within the clutch and input side elements and output side elements are tightened by an axial load to transmit a power and wherein a non-electrically operated pump mechanism is provided within the starting clutch.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a starting clutch mainly used in an automatic transmission of a vehicle and the like.  
           [0003]    2. Related Background Art  
           [0004]    [0004]FIG. 25 is an axial sectional view of a conventional starting clutch, showing an example of a conventional arrangement. A starting clutch  201  includes a wet type multi-plate clutch  203  and a damper  204  which are disposed within a case  210 . In the wet type multi-plate clutch  203 , friction plates  290  spline-fitted onto an outer periphery of a hub  280  and separator plates  300  spline-fitted into an inner periphery of a clutch case  310  are alternately arranged and dislodgment of these plates is prevented by a snap ring  212  disposed at an open end of the clutch case  310 .  
           [0005]    On the other hand, a piston  230  for applying a load to the friction plates  290  and the separator plates  300  is also disposed at the open end of the clutch case  310 . The piston  230  is operated by supplying hydraulic oil into an oil chamber  250  defined between the piston and an inner wall of the clutch case  310 , and the hydraulic oil is supplied through oil passages  271 ,  272  provided in members disposed at the inner peripheral side of the wet type multi-plate clutch  203  and oil passages  241 ,  243  provided in a drive shaft  240 . Lubrication of the starting clutch is effected by an electrical pump or an engine pump mainly used for operating the piston.  
           [0006]    While the operation of the piston of the wet type multi-plate clutch of the starting clutch has been effected by the hydraulic oil as mentioned above, in recent years, use of an electric motor or an electrically operated equipment such as a ball screw has been investigated in order to enhance accuracy of control of the operation of the piston. On the other hand, since it is not required that the hydraulic oil for operating the piston be supplied, it is considered that the electrical pump or the engine pump can be omitted, but, alternatively, it is required that means for supplying lubricating oil to the wet type multi-plate clutch be reserved.  
         SUMMARY OF THE INVENTION  
         [0007]    Therefore, an object of the present invention is to eliminate an electrically pump or an engine pump for operating a piston of a wet type multi-plate clutch and for supplying lubricating oil and to constitute an substitutive pump mechanism with a simple construction and to circulate the lubricating oil within a starting clutch.  
           [0008]    To achieve the above object according to the present invention, there is provided a starting clutch in which lubricating oil supplied from a drive shaft side is circulated within the clutch and input side elements and output side elements are tightened or engaged by an axial load to transmit a power and wherein a non-electrically operated pump mechanism is provided within the starting clutch.  
           [0009]    More specifically, the non-electrically operated pump mechanism is achieved by grooves or ports or vanes provided in or on at least one of rotary members constituting the starting clutch.  
           [0010]    Although the pump mechanism can be achieved by the grooves, ports or vanes provided in or on at least one of the members constituting the starting clutch as mentioned above, in a preferred embodiment of the present invention, the grooves are formed in a drive shaft, a piston, a pawl member of a damper, a clutch case, friction plates and separator plates, and the ports are formed in a base member and the vanes are formed on the base member, a hub and a case. Many grooves, ports of vanes are provided in various areas in order to enhance a circulating ability. The grooves, ports or vanes are formed in spiral or helical forms or have inclination angles with respect to a radial, axial or circumferential direction. Further, the inclination angles, number and arranging sites of the grooves or the vanes can be appropriately selected in accordance with a concrete configuration of the starting clutch and/or required pump capacity. Further, selection of grooves, ports or vanes can be appropriately determined.  
           [0011]    Further, the groves, ports or vanes having the pumping function can be obtaining by machining members constituting the starting clutch or by forming them integrally with such members. Alternatively, the grooves, ports or vanes may be formed in other members than the rotary members constituting the starting clutch and may be mounted to the rotary members. In a preferred embodiment, the former includes grooves formed in outer periphery of a drive shaft, ports formed in a base member, grooves formed in a piston, grooves formed in a pawl member of a damper, grooves formed in a clutch case, groves formed in friction plates and grooves formed in separator plates, and the latter includes grooves formed in inner periphery of the drive shaft, vanes formed on inner periphery of, the base member, vanes formed on a hub and vanes formed on the case. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is an axial sectional view of a starting clutch according to an embodiment of the present invention;  
         [0013]    [0013]FIG. 2 is an axial enlarged view showing main parts of the starting clutch of FIG. 1;  
         [0014]    [0014]FIG. 3 is a front view of a first vane wheel according to an embodiment of the present invention;  
         [0015]    [0015]FIG. 4 is an axial sectional view of the first vane wheel according to the embodiment;  
         [0016]    [0016]FIG. 5 is a front view of a piston according to an embodiment of the present invention;  
         [0017]    [0017]FIG. 6 is an axial sectional view of the piston according to the embodiment;  
         [0018]    [0018]FIG. 7 is a front view of the drive shaft according to an embodiment of the present invention;  
         [0019]    [0019]FIG. 8 is an axial sectional view of a cylindrical member according to an embodiment of the present invention;  
         [0020]    [0020]FIG. 9 is a side view of the drive shaft, looked at from a direction shown by the arrow A in FIG. 7;  
         [0021]    [0021]FIG. 10 is a sectional view of a second vane wheel, taken along the line  10 - 10  in FIG. 11;  
         [0022]    [0022]FIG. 11 is a side view of the second vane wheel according to an embodiment of the present invention;  
         [0023]    [0023]FIG. 12 is a front view of a base member according to an embodiment of the present invention;  
         [0024]    [0024]FIG. 13 is an axial sectional view of the base member according to the embodiment;  
         [0025]    [0025]FIG. 14 is a front view of a hub according to an embodiment of the present invention;  
         [0026]    [0026]FIG. 15 is a side view of the hub according to the embodiment;  
         [0027]    [0027]FIG. 16 is a front view of a friction plate according to an embodiment of the present invention;  
         [0028]    [0028]FIG. 17 is an axial sectional view of the friction plate according to the embodiment;  
         [0029]    [0029]FIG. 18 is a front view of a separator plate according to an embodiment of the present invention;  
         [0030]    [0030]FIG. 19 is an axial sectional view of the separator plate according to the embodiment;  
         [0031]    [0031]FIG. 20 is a front view of a clutch case according to an embodiment of the present invention;  
         [0032]    [0032]FIG. 21 is a rear view of the clutch case according to the embodiment;  
         [0033]    [0033]FIG. 22 is a side view of the clutch case according to the embodiment;  
         [0034]    [0034]FIG. 23 is a front view of a pawl member according to an embodiment of the present invention;  
         [0035]    [0035]FIG. 24 is an axial sectional view of the pawl member according to the embodiment; and  
         [0036]    [0036]FIG. 25 is an axial sectional view of a conventional starting clutch. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]    The present invention will now be explained in connection with embodiments thereof with reference to the accompanying drawings. Incidentally, in the drawings, the same elements are designated by the same reference numerals. It should be noted that the embodiments that will be described hereinbelow are merely examples of the present invention and so not limit the present invention.  
         [0038]    [0038]FIG. 1 is an axial sectional view showing an entire construction of a starting clutch according to an embodiment of the present invention. The starting clutch  1  includes a wet type multi-plate clutch  3  and a damper  4  which are disposed within a case  10 . In the wet type multi-plate clutch  3 , friction plates (friction engagement elements)  90  are spline-fitted onto a hub  80  and separator plates (friction engagement elements)  100  are spline-fitted into a clutch case  110  which is disposed in coaxial with the hub, and dislodgment of these plates is prevented by a snap ring  12  disposed at an open end of the clutch case  110 .  
         [0039]    A piston  30  is disposed at the open end of the clutch case  110 , and a loading spring  6  for applying an engaging load (tightening load) is disposed at an inner diameter side of the piston  30 . Further, a leaf spring  8  is disposed between the piston  30  and the separator plate  100  nearest to the piston to absorb or prevent shock during the engagement. Further, when a lever  2  is rotated in an anti-clockwise direction (FIG. 1) by an operation of a ball screw (not shown) to urge a release bearing  55  and a base member  70  to the right in FIG. 1, the piston  30  secured to the base member  70  is shifted to the right in opposition to the urging load of the loading spring  6 , thereby releasing the engagement load for the friction engagement elements. On the other hand, when the lever  2  is rotated in a clockwise direction (FIG. 1) by the operation of the ball screw, the piston  30  is shifted to the left in FIG. 1 by the urging load of the loading spring  6 , thereby applying the engagement load to the friction engagement elements. In this case, the base member  70  and the release bearing  55  are returned to the left in FIG. 1 by the loading spring  6 .  
         [0040]    The damper  4  is constituted by a retainer plate  7  secured to an inner wall of the case  10 , a damper spring  11  held by the retainer plate  7 , and a pawl member  120  secured to a side surface of the hub  80  and engaged by the damper spring  11 . With this arrangement, torque inputted from an engine is transmitted to the hub  80  through the case  10 , and vibration is absorbed by receiving the pawl member  120  secured to the hub  80  by means of the damper spring  11 . Incidentally, the torque is transmitted from the hub  80  to the clutch case  110  through the friction engagement elements and then is outputted to a crank shaft  40  spline-connected to an inner periphery of the clutch case  110 .  
         [0041]    Supplying of lubricating oil to the friction engagement elements (friction plates  90  and separator plates  110 ) is effected by supplying lubricating oil from a tank (not shown) to a space between the hub  80  and the piston  30  through a gap between the crank shaft  40  and a fixed shaft  5 , a cavity  9  and an oil port  71  provided in a second vane wheel  60  and the base member  70  (i.e., effected through the oil port  71  from the inner diameter side of the hub  80 ). Thereafter, the lubricating oil is discharged toward an outer peripheral side through an oil port  118  of the clutch case  110  and reaches an inner diameter side of the drive shaft  40  through a space between the clutch case  110  and the case  10  and then is returned to the tank. Incidentally, flow of the lubricating oil is shown by the arrows in FIG. 1.  
         [0042]    [0042]FIG. 2 is an enlarged view showing main parts of the starting clutch, illustrating the inner diameter side of the hub  80  in an enlarged scale. The circulation of the lubricating oil is effected by rotations of a first vane wheel  20  provided at the inner diameter side portion of the hub  80  and grooves  34  provided in the inner diameter portion of the piston  30 . Further, the lubricating oil is supplied to the friction engagement elements through an oil port  84  provided in the hub  80 .  
         [0043]    [0043]FIG. 3 is a front view of the first vane wheel  20  and FIG. 5 is an axial sectional view of the first vane wheel  20 . The first vane wheel  20  is made of synthetic resin and can be formed by injection molding and the like. The first vane wheel  20  is constituted by integrally arranging vanes  22  on an annular plate portion  21 . Each vane  22  is inclined in an radial direction so that, when the first vane wheel  20  is rotated in a clockwise direction in FIG. 3, the lubricating oil flows from an inner peripheral side to an outer peripheral side. Incidentally, the annular plate portion  21  is provided with substantially semi-circular notches  23 , and the annular plate portion is secured to a recipient member by fitting the notches onto the recipient member and by effecting caulking. Incidentally, as shown in FIG. 1, two first vane wheels  20  are provided within the hub  80  and within the case  10 .  
         [0044]    [0044]FIG. 5 is a front view of the piston  30  and FIG. 6 is an axial sectional view of the piston  30 . Spiral grooves  34  are formed in an inner peripheral side of an urging surface  31  of the piston  30  and in an opposite surface  32  opposite to an arrangement portion  33  against which the loading spring  6  abuts. Each groove  34  has a predetermined inclination angle with respect to the radial direction so that, when the piston  30  is rotated in an anti-clockwise direction in FIG. 5, the lubricating oil flows from the inner peripheral side to the outer peripheral side.  
         [0045]    FIGS.  7  to  9  show the drive shaft  40  shown in FIG. 1. FIG. 7 is a front view of the drive shaft  40 , FIG. 8 is an axial sectional view of a cylindrical member  50 , and FIG. 9 is a side view of the drive shaft  40 , looked at from a direction shown by the arrow in FIG. 7. The drive shaft  40  is provided at its outer peripheral surface with splines  46  which can be fitted in the clutch case  110 , and a spiral or helical groove  44  having a predetermined angle with respect to an axial direction. Due to the presence of the groove  44 , when the drive shaft  40  is rotated in a clockwise direction looked at from the direction A, the lubricating oil existing at the outer peripheral side flows to the right in FIG. 7.  
         [0046]    On the other hand, as shown by the broken line in FIG. 7, the drive shaft  40  is provided at its interior with an axially extending cavity  41  and an oil port  42  extending axially from the cavity  41  and having a diameter smaller than that of the cavity  41 . Further, there is provided an oil port  43  extending radially from a closed end portion of the oil port  42  and passing through a wall of the drive shaft. As apparent from FIG. 7, the cavity  41 , oil port  42  and oil port  43  are communicated with each other.  
         [0047]    The cylindrical member  50  shown in FIG. 8 is press-fitted into the cavity  41  from the direction A in FIG. 7. The cylindrical member  50  is provided at its interior with an oil port  51  and a helical groove  52  inclined at a predetermined angle with respect to the axial direction is formed in an inner wall of the oil port  51 . Due to the presence of the groove  52 , when the drive shaft  40  is rotated in the clockwise direction looked at from the direction A, the lubricating oil existing in the oil port  51  flows to the left in FIG. 7 and is then discharged out of the drive shaft  40  through the oil ports  42 ,  43  and is returned to the tank (not shown).  
         [0048]    As can be seen from the side view of the drive shaft  40  shown in FIG. 9, grooves  45  each having a pumping function are provided in a side surface of the drive shaft  40 . Similarly, grooves  53  are formed in a side surface of the cylindrical member  50 . The grooves  45  and the grooves  53  are radially extending grooves each having a predetermined angle with respect to the radial direction, and the grooves  45  are aligned with the grooves  53  to be continuously interconnected. That is to say, the groove  45  is communicated with the corresponding groove  53  to form an integral groove at a glance. In this case, when the oil port  43  is inclined with respect to the radial direction, the oil port can have a pumping function, and, in the illustrated embodiment, orientation of the inclination angle of the oil port is opposite to those of the grooves  45 ,  53  shown in FIG. 9.  
         [0049]    As shown in FIG. 9, a spline  46  comprised of mountain portions  46   a  and valley portions  46   b  is formed on the outer peripheral surface of the drive shaft  40  to be spline-connected to the clutch case  110 .  
         [0050]    [0050]FIGS. 10 and 11 show the second vane wheel  60  in detail. FIG. 10 is a sectional view taken along the line  10 - 10  in FIG. 11, and FIG. 11 is a side view of the second vane wheel  60 . The second vane wheel  60  has two annular side plates  62  between which vanes  61  are disposed in a condition that they are inclined with respect to the radial direction. When the vane wheel  60  is rotated in an anti-clockwise direction in FIG. 10, the lubricating oil flows toward an outer diameter direction. Further, small projections  63  are formed on outer peripheral edges of the annular side plates  62  so that the vane wheel can be attached to the base member  70  (described later) by means of such small projections.  
         [0051]    [0051]FIGS. 12 and 13 show the base member  70  in detail. FIG. 12 is a front view of the base member  70  and FIG. 13 is an axial sectional view of the base member. The base member  70  is provided at its outer periphery with an annular recess  75  and an annular extension  76 . The base member  70  is secured or fixed by arranging a seal member  78  (refer to FIG. 1) on a left (in FIG. 13) side surface  76   a  of the extension  76  and fitting a snap ring into the recess  75 . On the other hand, the piston  30  is secured to a right (in FIG. 13) side surface  76   b  of the extension  76  welding.  
         [0052]    Further, the base member  70  has oil ports  71  passing through the base member from its inner periphery to its outer periphery, and opening portions  72  wider than the oil ports  71  are formed in the inner peripheral side. Each oil port  71  has a predetermined inclination angle with respect to the radial direction as shown by the broken line in FIG. 12. When the base member  70  is rotated in an anti-clockwise direction in FIG. 12, the lubricating oil flows from the inner peripheral side to the outer peripheral side. Incidentally, the second vane wheel  60  is fixed or secured by fitting the vane wheel into an annular recessed groove  73  formed in the inner peripheral surface of the base member  70  and by attaching a snap ring into an annular groove  74 .  
         [0053]    [0053]FIGS. 14 and 15 show the hub  80  in detail. FIG. 14 is a front view of the hub  80  and FIG. 15 is a side view of the hub  80 . A spline is formed on an outer peripheral flange  81  of the hub  80 . The spline is constituted by mountain portions  81   a  and valley portions  81   b . A plurality of oil ports  84  (shown in FIG. 2 as section) are formed in the valley portions  81   b  of the spline along the spline. The spline has a predetermined inclination angle with respect to the axial direction so that, when the hub  80  is rotated in a clockwise direction in FIG. 14, the lubricating oil is apt to be flown to the right in FIG. 1 or FIG. 15.  
         [0054]    However, since the inclination angle is selected to be so smaller that the inclination angle does not affect a bad influence upon the operation of the friction plates  90  and the separator plates  100 , such inclination angle gives an effect mainly at a low speed rotation area. Although not shown, each oil port  84  also has a predetermined inclination angle with respect to the radial direction so that, when the hub is rotated in a clockwise direction in FIG. 14, the lubricating oil flows from the inner peripheral side to the outer peripheral side. Incidentally, the inclination is angled leftwardly from the inner peripheral side to the outer peripheral side. Further, an inner peripheral surface  82  of the hub is attached to an inner diameter side flange of the case  10  and is secured by a snap ring. Further, the pawl member  120  which will be described later is secured to a rear surface  83  of the hub  80  by welding.  
         [0055]    [0055]FIGS. 16 and 17 show the friction plate  90  used in the embodiment of the present invention in detail. FIG. 16 is a front view of the friction plate  90  and FIG. 17 is an axial sectional view of the friction plate. The friction plate  90  is constituted by adhering a friction material  92  on an annular core plate  91  having a spline at its inner peripheral edge. The spline includes mountain portions  94   a  and valley portions  94   b . Grooves  93  each an inclination angle with respect to the radial direction are formed in the friction material  92 .  
         [0056]    When the friction plate  90  is rotated in an anti-clockwise direction in FIG. 16, the lubricating oil flows from the inner diameter side to the outer diameter side. By supplying the lubricating oil to the friction materials  92 , the friction plates and the separator plates (described later) are cooled. Incidentally, the grooves  93  can be obtained by urging or cutting the friction material or can be obtained by adhering a plurality of friction material segments with a predetermined gap therebetween. According to the grooves formed by the combination of the segments, since the depth of the groove can be increased, the greater pumping action can be achieved.  
         [0057]    [0057]FIGS. 18 and 19 show the separator plate  100  in detail. FIG. 18 is a front view of the separator plate  100  and FIG. 19 is an axial sectional view of the separator plate. In FIG. 1, the separator plate  100  is disposed in adjacent to the snap ring  12 . Further, each separator plate  100  is provided at its outer peripheral edge with a spline fitted into the inner periphery of the clutch case  110 . The spline includes mountain portions  102   a  and valley portions  102   b . Further, grooves  103  communicating between the outer periphery and the inner periphery and each having a predetermined inclination angle with respect to the radial direction are formed in a surface  102  which is not contracted with the friction plate  90 . When the separator plate  100  is rotated in an anti-clockwise direction in FIG. 18, the lubricating oil flows from the inner diameter side to the outer diameter side.  
         [0058]    FIGS.  20  to  22  show the clutch case  110  in detail. FIG. 20 is a front view of the clutch case  110 , FIG. 21 is a rear view of the clutch case and FIG. 22 is a side view of the clutch case. As shown in FIG. 20, the clutch case  110  has inner wall surfaces  118   a ,  118   b ,  118   c  extending radially, and grooves  111   a  and  111   b  each having a predetermined inclination angle with respect to the radial direction are formed in the inner walls  118   a    118   b , respectively, and projections  113  for supporting the loading spring  6  are formed on the inner wall  118   c.    
         [0059]    Further, mountain portions  114   a  and valley portions  114   b  of a spline to be fitted onto the separator plates  100  are formed an axially extending portion at the outer diameter side, and the spline also has a predetermined inclination angle with respect to the axial direction (refer to FIG. 22). On the other hand, as shown in FIG. 22, grooves  115   a ,  115   b ,  115   c  each having a predetermined inclination angle with respect to the radial direction are formed in outer wall surfaces  117   a ,  117   b ,  117   c  extending radially outside of the clutch case  110 . Further, as shown in FIG. 22, there are provided a plurality of oil ports  119  passing through the clutch case  110  from the inner periphery to the outer periphery. Although not shown, each oil port  119  also has a predetermined inclination angle with respect to the radial direction so that, when the clutch case  110  is rotated in an anti-clockwise direction in FIG. 20, the lubricating oil flows form the inner peripheral side to the outer peripheral side.  
         [0060]    Incidentally, the inclination angle is inclined to the right from the inner peripheral side to the outer peripheral side. With this arrangement, when the clutch case  110  is rotated in the anti-clockwise direction in FIG. 20, the lubricating oil is supplied more positively toward the outer peripheral side of the clutch case  110  by a centrifugal force and the pumping action of the grooves  111   a ,  111   b  and the oil ports  119  and then is routed to the rear side of the clutch case  110  by the pumping action of the spline having the inclination angle and then is sucked toward the inner peripheral side by the pumping action of the grooves  115   a ,  115   b ,  115   c.    
         [0061]    [0061]FIGS. 23 and 24 show the pawl member  120  of the damper in detail. FIG. 23 is a front view of the pawl member  120  and FIG. 24 is an axial sectional view of the pawl member. As shown in FIG. 1, the pawl member  120  is provided at its outer periphery with a fitting portion  122  engaged by the damper spring  11 . Further, grooves  124 ,  125  each having a predetermined inclination angle with respect to the radial direction are formed in a radially extending bottom surface  121 . Further, grooves  126  each having a predetermined inclination angle with respect to the axial direction are formed in an inner peripheral surface  127 . When the pawl member  120  is rotated in an anti-clockwise direction in FIG. 23, the lubricating oil is supplied toward the inner peripheral surface  127  by a centrifugal force and the pumping action of the grooves  124 ,  125  and is flown to the left in FIG. 24 by the pumping action of the grooves  126 .  
         [0062]    Although the present invention can be carried out in accordance with the above-mentioned embodiment, the present invention is not particularly limited to such an embodiment. For example, at least one of the vanes  22 ,  61  of the first vane wheel  20  and the second vane wheel  60 , and at least one of the groves formed in various members may be used, but, all of the vanes and the grooves may not always be used. Further, the number and the inclination angles of the vanes  22 ,  61  and/or grooves of the members can be selected appropriately. Further, while the plural oil ports  84 ,  119  were illustrated in the drawings, single oil port may be used.  
         [0063]    As mentioned above, according to the starting clutch of the present invention, the following effect can be achieved.  
         [0064]    An electrical pump or an engine pump for effecting the operation of the starting clutch and the supplying of the lubricating oil can be eliminated, and a substitutive pump mechanism can be obtained with a simple construction to circulate the lubricating oil within the starting clutch.