Parking lock arrangement for continuously variable V-belt transmission

According to the present invention, a parking gear is rotatable with that rotary member which is in driving connection with a differential. The rotary member is released from a continuously variable V-belt transmission unit upon setting a manual shift lever in "P" position. When the manual shift lever is set to the "P" position, the parking gear is locked.

BACKGROUND OF THE INVENTION 
The present invention relates to a continuously variable V-belt 
transmission, and more particularly to a parking lock arrangement for a 
continuously variable V-belt transmission. 
SUMMARY OF THE INVENTION 
According to the present invention, a parking gear is rotatable with the 
rotary member which is in driving connection with a differential. The 
rotary member is selectively connectable with a continuously variable 
V-belt transmission unit. When a manual shift lever is set to a parking 
position, the parking gear is locked. 
According to a specific feature of the present invention, a manual lever 
and a parking lever are fixedly attached to a shaft which is rotatably 
supported by a case. 
An object of the present invention is therefore to provide a parking lock 
arrangement for a continuously variable V-belt transmission which is 
simple and reliable in operation.

DESCRIPTION OF EMBODIMENTS 
Referring to the accompanying drawings, a first embodiment is described 
hereinafter in connection with FIGS. 1 to 3. 
As illustrated in FIG. 1, an engine output shaft 2 which is in rotary 
unison with a crankshaft (not illustrated) has mounted thereon a 
hydrodynamic transmission unit in the form of a torque converter 12 (it 
may be replaced with a fluid coupling) which includes a pump impeller 4, a 
turbine roller 6, a stator 8 and a lock-up clutch 10. The lock-up clutch 
10 is coupled with a turbine runner 6 and is axially slidable, the lock-up 
clutch 10 cooperating with a converter shell 4a coupled with the engine 
output shaft 2 integral with the pump impeller 4 to form a lock-up clutch 
oil chamber 14. In operation, when the oil pressure within this lock-up 
clutch oil chamber 14 drops below the oil pressure within the torque 
converter 12, this pressure difference urges the lock-up clutch 10 against 
the member 4a for unitary rotation with same. The turbine runner 6 is 
splined to one end portion of a drive shaft 22 rotatably supported by a 
transmission case 20 via bearings 16 and 18. A drive pulley 24 is mounted 
on the drive shaft 22 between the bearings 16 and 18. 
The drive pulley 24 comprises an axially fixed conical disc fixedly secured 
to the drive shaft 22 and an axially movable conical disc 30 which is 
arranged in a face-to-face relationship with the axially fixed conical 
disc 26 to define a V-shaped pulley groove and which is axially slidable 
along the drive shaft 22 by the oil pressure acting within the drive 
pulley cylinder chamber (not illustrated). The drive pulley 24 is 
drivingly connected to a driven pulley 34 by a V-belt 32, the driven 
pulley 34 being mounted on a driven shaft 40 rotatably supported by the 
transmission case 20 by means of bearings 36 and 38. The driven pulley 34 
comprises an axially fixed conical disc 42 fixedly secured to the driven 
shaft 40 and an axially movable conical disc 46 which is arranged in a 
face-to-face relationship with the axially fixed conical disk 42 to define 
a V-shaped pulley groove and which is axially slidable along the driven 
shaft 40 by the oil pressure acting within the driven pulley cylinder 
chamber (not illustrated). 
A rotary member in the form of forward drive gear 50 which is rotatably 
supported by the driven shaft 40 is engageable with the fixed conical disc 
42 via a forward multiple disc clutch 48, the forward drive gear 50 
meshing with a ring gear 52. Fixed to the driven shaft 40 is a reverse 
drive gear 54 which meshes with an idle gear 56. The idle gear 56 is 
engageable with an idle shaft 60 via a reverse multiple disc clutch 58. 
The idle shaft 60 has fixed thereto another idle gear 62 which meshes with 
the ring gear 52. (It is to be understood that in the case of FIG. 1 for 
ease of illustration the idle gear 62, idle shaft 60 and reverse multiple 
disc clutch 58 are illustrated as displaced from their proper positions so 
that the idle gear 62 appears to be out of meshing with the ring gear 52, 
but they actually mesh with each other as shown in FIG. 2.) Connected to 
the ring gear 52 for rotation therewith are a pair of pinion gears 64 and 
66, and a pair of side gears 68 and 70 meshing with this pair of pinion 
gears 64 and 66 to form a differential 67 and coupled with the output 
shafts 72 and 74, respectively. 
The output shafts 72 and 74 are rotatably supported by bearings 76 and 78, 
respectively, and extend in the opposite directions outwardly of the case 
20. These output shafts 72 and 74 are supposedly coupled with road wheels, 
not illustrated. On the right of the bearing 18 is arranged an internally 
meshing gear type oil pump 80 serving as a source of oil pressure for an 
hydraulic control apparatus. The oil pump 80 is driven by the engine 
output shaft 2 through an oil pump drive shaft 82 extending through the 
hollow drive shaft 22. 
Rotational power is fed from the engine output shaft 2 to the continuously 
variable V-belt transmission including the torque converter 12 with the 
lock-up clutch 10, continuously variable V-belt transmission unit and 
differential 67. The power is delivered to the torque converter 12, drive 
shaft 22, drive pulley 24, V-belt 32, driven pulley 34, driven shaft 40 in 
this sequence, and further to the forward drive gear 50, ring gear 52, 
diferential 67 and then to the output shafts 72 and 74 to rotate them in 
the forward direction when the forward multiple disc clutch 48 is engaged 
with the reverse multiple disc clutch 58 released, or delivered further to 
the reverse drive gear 54, idle gear 56, idle shaft 60, idle gear 62, ring 
gear 52, differential and the output shafts 72 and 74 to rotate them in 
the reverse direction when the reverse multiple disc clutch 58 is engaged 
with the forward multiple disc clutch 48 released. During this 
transmission of power a rotational ratio between the drive pulley 24 and 
driven pulley 34 can be varied by axially displacing the movable conical 
disc 30 of the drive pulley 24 and the movable conical disc 46 of the 
driven pulley 34 in a manner to vary the effective radius of running 
diameter of the V-belt 34. For example, if the width of the V-shaped 
groove of the drive pulley 24 is increased and at the same time the width 
of the V-shaped pulley groove of the driven pulley 34 is reduced, the 
radius of the diameter on the drive pulley 24 contacting with the V-belt 
reduces and the radius of the diameter on the driven pulley 34 contacting 
with the V-belt increases, thus providing a high reduction ratio. If the 
movable conical discs 30 and 46 are displaced in the reverse directions, 
the reduction ratio decreases. During the transmission of power, although 
the torque converter 12 has a state wherein it effects the torque 
multiplication or a state wherein it serves as a fluid coupling depending 
upon operation state, since the torque converter 12 is provided with the 
lock-up clutch 10 attached to the turbine runner 6, the engine output 
shaft 2 can be mechanically and directly coupled with the drive shaft 22 
if draining the oil pressure is discharged from the lock-up clutch oil 
chamber 14 to allow the lock-up clutch 10 to be pressed against the 
converter shell 4a integral with the pump impeller 4. 
Referring particularly to FIGS. 2 and 3, a parking lock is explained. In 
FIG. 3 which specifically illustrates the structure of the parking lock, 
the fixed conical discs 26, 42, movable conical disc 30, 46 and V-belt 32 
are illustrated by phantom line. 
A pawl 83 is pivoted to the transmission case 20 by a pin 84 in such a 
matter as to engage a parking gear 51 which is fixedly attached to the 
forward drive gear 50 for rotation therewith. The pawl 83 has a tooth 83a 
and a back portion 83b and is biased by a spring 85 in a direction toward 
a disengaged position (counter clockwise direction viewing in FIG. 2). A 
parking rod 90 is arranged between the back portion 83b of the pawl 83 and 
two balls 89 which are biased by a spring 88 against a support member 87 
attached to the transmission case 20 by a screw 86. The parking rod 90 is 
formed at its one edge with an enlarged diameter portion 90a . The other 
end of the parking rod 90 is linked to the parking lever 91. The enlarged 
diameter portion 90a is arranged such that it aligns with the balls 89 and 
the back portion 83b of the pawl 83 as shown in FIG. 3 when a manual shift 
lever for the parking outer lever 93 is set in "P" position. The parking 
lever 91 is fixedly attached to a control shaft 92 for rotation therewith. 
The control shaft 92 has one end pivoted to the transmission case 20 and 
connected to be rotatable by the parking outer lever 93. The other end of 
the shaft 92 extends into the inside of the transmission and is pivoted to 
a portion of a valve body 94 (may be pivoted to the transmission case 20) 
and fixedly attached to a lever 97 for actuating the spool 104 of manual 
selector valve. The lever 97 engages with the spool 104 slidably disposed 
within the valve body 94, i.e., a hydraulic control apparatus, fixedly 
secured to the bottom of the transmission case 20. With this manual valve, 
the forward multiple disc clutch 48 and the reverse multiple clutch 58 are 
selectively engaged. The parking lever 93 is linked by a link mechanism, 
not illustrated, to the manual shift lever provided adjacent the driver's 
seat and is arranged to angularly moved by predetermined angles in respose 
to the corresponding positions "P", "R", "N", "D", and "L" of the manual 
shift lever. Also formed on the parking lever 91 is a portion 91a formed 
on the outer periphery of a sector for being engaged by a ball 96 biased 
by a spring 95. 
Hereinafter, the operation is explained. When the manual shift lever is set 
in "P" position, the control shaft 92 is rotated via the parking outer 
lever 93 to cause the parking lever 91 to rotate counterclockwise viewed 
in FIG. 3, thus pulling the parking rod 90. This causes the enlarged 
diameter portion 90a of the parking rod 90 to ride on the balls 89, thus 
pressing the back 83b of the pawl 83. Thus, the pawl 83 is urged to an 
engaged position wherein the tooth 83a meshes with the gear 51. Therefore, 
the parking gear 51 is held stationary against rotation. The parking gear 
51 is integral with the forward drive gear 50, the forward gear 50 meshing 
always with the ring gear 52 of the differential 67, causing the output 
shafts 72 and 74 to be held stationary. When, in "P" position, the 
actuation of the spool 104 of manual selector valve releases the forward 
multiple disc clutch 48, thus completely isolating the parking gear 51 
from power transmission state with the driven pulley 34, allowing the 
power transmission system upstream of the driven pulley 34 to freely 
rotate even in this parking state. Rotation of the shaft 92 causes 
rotation of the lever 97 for the manual selector valve, thus causing the 
spool 104 of the manual valve to move axially. The parking lever 91 is 
formed with check grooves corresponding to "P", "R", "N", "D", "L" 
positions of the manual shift lever, respectively, and since the ball 96 
is biased by the spring 95 to engage these grooves selectively, the 
parking lever 91 is stopped when the ball 96 engages a selective one of 
the grooves and the spool 104 is maintained in the corresponding position 
to the selective one of "P", "R", "N", "D", "L" positions. The oil 
pressure control apparatus with the valve body 94 is constructed such that 
the transmission is conditioned in the one of forward drive state or 
reverse drive state or neutral state depending upon the position of the 
spool 104. 
A parking gear 51A may be formed on a rotary member integral with the idle 
shaft 60 as shown in FIG. 4. The idle shaft 60 is always in power 
transmission state with the ring gear 52 via the idle gear 62 and 
furthermore the idle shaft 60 is isolated from the power transmission 
state with the driven pulley 34 when in "P" position, hence substantially 
the same function and effect as obtained with regard to the first 
embodiment are obtained. 
As previously described, the parking gear is fixedly attached to the rotary 
member of the power train which is always in a power transmission state 
with the ring gear of the differential, but is out of transmission state 
with the continuously variable V-belt transmission unit upon selecting the 
parking state when the forward drive clutch is released, so that even if, 
during the parking, engine is caused to race, a power transmission system 
from the engine upto the driven pulley rotate freely, thus causing no 
unreasonably great force to be impressed on the V-belt transmission unit, 
thus causing no damage. 
Since the lever for actuating the manual selector valve and the parking 
lever for actuating the pawl are fixedly attached to the single control 
shaft which is rotatable by the manual shaft lever provided adjacent a 
driver's seat, a reliability has been enhanced. 
With the control shaft, it is now possible to link the manual selector 
valve and the parking lever even if they are disposed on the opposite 
sides of a rotatable member, such as the drive shaft. 
Furthermore, in the case a continuously variable V-belt transmission 
provided with a drive pulley and a driven pulley which are larger in outer 
diameter is used to propell a motor vehicle, the driven pulley should be 
arranged at the upper portion of the transmission so as to secure a 
minimum height from the road surface, while, the hydraulic control 
apparatus provided with a manual selector valve should be arranged at the 
lower portion of the transmission for the need to suck in oil and 
discharge of oil and for the ease of manipulation of the manual selector 
valve. This has been accomplished with the use of single control shaft.