CA1143183A - Speed-changing transmission device for vehicles - Google Patents
Speed-changing transmission device for vehiclesInfo
- Publication number
- CA1143183A CA1143183A CA000373215A CA373215A CA1143183A CA 1143183 A CA1143183 A CA 1143183A CA 000373215 A CA000373215 A CA 000373215A CA 373215 A CA373215 A CA 373215A CA 1143183 A CA1143183 A CA 1143183A
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- CA
- Canada
- Prior art keywords
- speed
- changing
- backward
- shaft
- gear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT OF THE DISCLOSURE
A speed-changing transmission device for vehicles includes a speed changing shaft connected to rear wheels and disposed at the rear side of an input shaft driven by an engine coaxially with the input shaft, a counter shaft mounted in parallel with the speed-changing shaft and driven by the input shaft, and forward and backward speed-changing gear systems through which the speed-changing gear is connected to the counter shaft to constitute a speed-changing transmission mechanism. A forward one-way clutch is disposed between the input shaft and the speed-changing shaft of the speed-changing mechanism. In the power transmission path formed by the backward speed-changing gear system, provided is a backward clutch and a backward one-way clutch parallel with the backward clutch.
The connection between the engine and the speed-changing shaft is maintained even when the clutch for changing the speed is turned into "OFF" state during parking of the vehicle, so that an engine braking effect is obtained to prevent the vehicle from starting naturally.
A speed-changing transmission device for vehicles includes a speed changing shaft connected to rear wheels and disposed at the rear side of an input shaft driven by an engine coaxially with the input shaft, a counter shaft mounted in parallel with the speed-changing shaft and driven by the input shaft, and forward and backward speed-changing gear systems through which the speed-changing gear is connected to the counter shaft to constitute a speed-changing transmission mechanism. A forward one-way clutch is disposed between the input shaft and the speed-changing shaft of the speed-changing mechanism. In the power transmission path formed by the backward speed-changing gear system, provided is a backward clutch and a backward one-way clutch parallel with the backward clutch.
The connection between the engine and the speed-changing shaft is maintained even when the clutch for changing the speed is turned into "OFF" state during parking of the vehicle, so that an engine braking effect is obtained to prevent the vehicle from starting naturally.
Description
Title of the Invention SPEED-CHANGINC. TRANSMISSION DEVICE FOR
VEHICLES
Background of the Invention:
Field of the Invention The present invention relates to a speed-changing transmission device for vehicles and, more particularly, to an improvement in a speed-changing transmission device for vehicles, of the type having a counter shaft adapted to be driven by an input shaft which in turn is driven by an engine,.a transmission shaft for driving a wheel axle or the like, the counter shaft and the speed-changing shaft being connected to each other through a forward transmission gear system and also through a backward transmission gear system, and clutches disposed in respective transmission paths and adapted to be selectively used to effect the changing of the speed.
Description of the Prior Art In the conventional speed-changing transmission device for vehicles, when, for example, the pressure of the oilifor operating the clutch for:changing the speed is lowered due to the stop of the engine during parking, the clutch takes the "off" state to disconnect the driving wheel axle or the like from the engine. In this state, it is not possible to utilize the engine - 1 - ~"~
i~
., , ~ . , .
, braking effect.whlch is quite useful particularly when the vehicle is parked on a steel slope. In such a case, if the parking brake is opera-ted insufficiently, the vehicle will-naturally start dangerously. It is also to be pointed out that, in the event of an:
excessive discharge~of the battery, it is not possible to start the engine by pushing the vehicle manually, because the driving..wheel axle is disconnected from the engine.
Summary of the Invention It is, thereEore, an ohject of the invention to provide a speed-changing transmission device in which, even when the clutch for the speed changing becomes inoperative or to take the lloff" state during parking, the direct connectio~..is:maintàined between~the engine and the driving wheel axle or the like to ensure the engine braking effect during parking.
According to the invention, the above-stated object is achieved by a speed-changing transmission device having the following featuresO
Namely, the invention provides a speed-changing transmission device comprising: a speed-changing gear for transmitting the torque to the driving wheel axle or the like and mounted.at the rear side of an.inputs shaft drivenl.by the engine coaxially with`the input shaft, 3:~83 a counter shaft mounted in parallel with the speed-changing shaft and carrying a counter gear always meshing with an input gear:on the input shaft, a forward speed changing-gear system provided on the speed-changing shaft and:the counter shaft, the forward speed changing gear system including a forward speed-changing gear and a forward counter gear which are meshing with each other and adapted to transmit the rotation of the counter shaft to the speed-changing shaft at a speed reduced as compared with the speed of the input shaft or in the reverse direction to the rotation of the input shaft, a backward speed-changing gear system provided on the speed-changing shaft~and:~he counter shaft, the backward speed--changing gear system including a backward speed changing gear, a backward idle gear and a backward counter gear, a clutch disposed between the input shaft and the speed-changing shaft and clutches disposed in the transmission paths provided by respective speed-changing gear systems between the input shaft and the speed-changing shaft, the.. clutches being usabla selectively, a one-way clutch for forward driving disposed between the input shaft and the speed-changing shaft, and a one-way clutch for backward driving disposed between the speed-changing shaft and the backward speed-changing gear system or between the ~ ~3~83 counter shaft and the backward speed-changing gear system.
Brief Descript-ion of the Drawings The invention is illustrated by way of example in the accompanying drawings wherein:
Fig. 1 is a vertical sectional side elevational view of the front portion of mission case of a powered agricultural machine to which a device of a first embodiment of the invention is applied;
Fig. 2 illustrates the power transmission system of the embodiment shown in Fig. 1;
Figs. 3A to 3D are illustrations explanatory of the operation of forward and backward one-way clutches in the embodiment shown in Fig. l;
More particularly:
Fig. 3A views show state of engine forward driving, respective views, forward and backward;
Fig. 3B views show state of engine backward driving, respective views, forward and backward;
Fig. 3C views show state of engine stopping forward driving: rotates on its own axis, respective views, forward and backward;
Fig. 3D views show state of engine stopping backward driving: rotates on its own axis, respective views, forward and backward;
Fig. 4 illustrates the power transmission system of a second embodiment of the invention; and Figs. 5A to 5D are illustrations explanatory of the operation of forward and backward one-way clutches in the , .
.' `~ ' ' : -'-. ~
embodiment shown in Fig. 4.
More particularly:
Fig. 5A views show state of engine forward driving,respective views, forward and backward;
Fig~ 5B views show state of engine backward driving, respective views, forward and backward;
Fig. 5C views show state of engine stopping forward driving: rotates on its own axis, respective views, forward and backward;
Fig. 5D views show state of engine stopping backward driving: rotates on its own axis, respective views, forward and backward;
Description of the Preferred Embodiments:
Hereinafter, preferred embodiments of the invention applied to a powered agricultural machine will be described with reference to the accompanying drawings.
As will be seen from Fig. 1 showing a vertical section, as well as from Fig. 2 showing the power transmission system schematically, an engine 1 has a -4a-:, ' ' ' '' crank shaft to which connected is an input shaft 3 through a maln clutch 2. A speed-changing shaft 4 is suppo~ted at its front end by a bearing 5 and is disposed behind the input shaft 3. The rear end o the speed-changing shaft 4 is supported by a mission .
case 7 through a medium of a bearing 6. A counter shaft 8 is mounted in parallel with the speed-changing shaft 4 and supported by bearings 9,10 on the mission case 7. A counter gear 11 of small diameter for backward driving and counter gears 12b,12c for forward driving having different diameters are carried by the counter shaft 8. ~ speed-changing gear 14 for backward driving, rotatably mounted on the speed-changing shaft through a bearing 13 meshes through an idle gear 15 for backward driving with a counter gear 11 for backward driving to constitute a backward speed-changing gear system.
Speed changing gears 18b,18c for forward driving, rotatably mounted on the speed-changing shaft 4 through bear-ngs 16,17, engage with counter gears 12b, 12c for forward driving, while anuinput gear 3a of a smàll diameter formed at the rear portion of the input shaft 3 meshes with a counter gear 12a of a large diameter to constitute a forward speed-changing gear system.
A clutch 20 for hackward driving is connected '~
between the backward speed-changing gear 14 and the speed-changing shaft 4. Also, provided are clutches 21a,21b,21c for forward driving so as to connect speed-changing gears 18b,18c to the clutch shaft 4.
These clutches are adapted be operated selectively.
A second speed-changing shaft 22 is connected to the speed-changing shaft 4 through a gear as shown in Fig. 2. A group 23 of shift gears slidable on~y in the axial direction along the second speed-changing shaft 22 is adapted to be brought into engagement with a group 25 of second counter gears selectively by means of a mechanical speed-changing device 26. A
drive pinion shaft 28 drivingly connected to the second speed-changing shaft 22 through a clutch 27 is adapted to drive left and right rear driving wheels 31, 31 of the vehicle through a rear wheel differential gear device 29. The rear wheels 31 are provided with respective brakes. .:::
The construction of the backward clutch 20 and the forward clutches 21a to 21c will be explained herein-under with specific reference to the clutch 21a for the forward driving by way of example. The clutch 21a has a clutch housing 32 fitted to the speed-changing shaft 4 and accomodating in an oil-tight manner a piston 33 which is biased in the d~sengag~n~ diæection~by means of .. , .. .- . ,. . . ~ . ~
~3~3 a spring 33. A friction disc 35 fits in the clutch housiny 32 slidably only in the axial direction, while a friction disc 36 is fitted to a hub of an input gear 3a slidably only in the axial direction. A
working oil deliv~red by an oil pump 37 is introduced into a speed-changing switching valve 39 through a relay cylinder 38 fitting the rear end of the speed-changing shaft 4. As the driver manipulates a speed-changing lever 40, the spool 41 of the switching valve 39 is slided in the axial direction to distribute the oil selectively from an oil passage 7a in the mission case 7 and an oil passage 38a in the relay cylinder 38 via the oil passages a,b... of the clutch housings of clutches selected by the speed-changing lever 40. For instanee, assuming here that the pressurized oil is supplied to the rear side of a piston 34 via the oil passage a, the piston 34 makes the frictional discs 35,36 engage with eaeh other thereby to eonnect the input gear 3a to the speed-ehanging shaft 4.
Thus, the power transmission provided by the mutual engagement between the forward eounter gear 12e and the forw-rd speed-changing gear 18c, caused by the engaging operation of the forward clutch 21c, provides a rotation speed of first forward speed (V1),which is the lowest of the forward speeds, to the speed-changing shaft 4. Slmilarly, a Eorward second speed V2 is given throuyh the mutual engagement of the forward counter gear 12b and the forward speed-changing gear 18b as the forward cluth 21b is brought into "ON" state, and the highest forward speed V3 is imparted to the speed-changing shaft 4 as the forward clutch 21a is put into operation, by a direct connection. Also, as the backward clutch 20 is put into operation, a backward first speed R1 is imparted to the speed-changing shaft 4 through the backward counter gear 11, backward idle gear 15 and the backward speed-changing gear 14.
The unput gear 3a is coupled to the speed-changing gear 4 through a one-way clutch 42 which can deliver to the input shaft 3 only the forward driving power from the speed-changing shaft 4. Namely, as shown in Fig. 3a, an outer wheel 42a fitted around the input gear 3a is adapted to rotate counter-clockwise as viewed from the rear side. This outer wheel 42a makes a counter-clockwise rotation relati~ely to an inner wheel 42b fitting the speed-changing shaft 4 which rotates in the same direction as the input shaft 3 at the forward first or second speeds Vl,V2 which is lower than the speed of the input shaft 3. Therefore, the input gear 3a and the speed-changing shaft 4 rotate 3~3 freely from each other. The outer wheel 42a making a counter-clockwise rotation relatively to the inner wheel 42b and the input gear 3a can rotate freely from each other also when the speed-changing shaft 4 makes a clockwise rotation as shown in Fig. 3b. However, when in~the state shown in Fig. 3c in which the inner wheel 42b makes a counter-clockwise rotation relatively to the outer wheel 42a, the speed-changing gear 4 and the input gear 3a rotate as a unit with each other by the action of the one-way clutch 42.
The backward speed-changing gear 14 is connected to the speed-changing shaft 4 through a one-way clutch 43 which can deliver to the backward speed-changing gear 14 only the backward driving power from the speed-changing shaft 4. Namely, an outer wheel 43a fits to the speed-changing gear 14 which is adapted to rotate only in the clockwise direction as viewed from the rear side as shown in Fig. 3a. This outer wheel 43a rotates freely from ans inner wheel 43b which rotates counter-clockwise at the forward first or second speed Vl,V2. However, in the state shown in Fig. 3d in which the inner ring 43b makes a clockwise rotation reatively to the outer wheel 43a as mentioned later, the speed-changing gear 14 and the speed-changing shaft 4 rotate as a unit with each other by the action of ~3~3 the one-way clutch 43.
In another embodiment shown in Fig. 4, a backward speed-changing gear 44 is fitted to the speed-changing shaft 4, while a backward counter gear 45 for engagement with the backward idle gear 15 is rotatably carried by the counter shaft 8 through a bearing 46.
The backward counter gear 45 is connected to the cou~ter shaft 8 through a backward clutch 47 having a clutch housing fitting the counter shaft 8. Also, a one-way clutch 48 for backward driving is dis~osed to provide a connection between the backward clutch 48 and the counter shaft 8. The one-way clutch 48 is of the type capable of delivering to the counter shaft 8 only the forward driving power from the backward counter gear 45.
Namely, when the inner whhel'48a'fit~ing-to'-the counter shaft 8 rotating clockwise as viewed from the rear side makes a clockwise rotation relatively to the outer wheel 48b fitting to the backward counter gear 45 as shown in ~ig. 5a, the inner wheel 48a and the outer wheel 48b can rotate independently of each other.
However,'in the state shown in, for example, Fig. 5d in which the outér wheel 48b makes a clockwise rotation relatively to the inner wheel'48a, the backward counter gear 45 and the counter shaft 8 rotate'as a unit with 3~3 each other by the action of the one-way clutch 48.
In the powered agricull:ual machine as shown in the drawings, the torque of the counter gear 12a is adapted to be transmitted to a power shaft 51 through a PTO clutch 49 and a PTO gear unit 50.
In the illustrated and described embodlments, the forward speed changing gear system and the backward speed-changing gear system are adapted to be operated by means o~ hydraulically actuated clutches. The invnetion, however, can be equally applied to the systems having mechanically actuated clutches.
The operation of the speed-changing transmission device of the invention can be achieved even when the forward clutch 2la is eliminated.
In the speed-changing transmission device of the first:embodiment o~-the invention, as;thé orward clutches 21c,21b are operated selectlvely, the speed-changing shaft rotates at a forward first or second speed Vl,V2 which is higher than that of the input shaft 3.
Therefore, the inout gear 3a, rotating counter-clockwise relatively to the speed-changing shaft 4 as viewed from the rear side can rotate freely. As to the back-ward onw-way clutch 43, the backward speed-changing gear 14 rotating clockwise relatively to the speed-changing 3~i33 shaft 4 can be rotated freely. Therefore, thetorque of the input shaft 3 is transmitted through the forward clutch 21c or 21b to the speed-changing gear 4 to drive the latter at a reduced speed of forward first or second speeds Vl,V2 corresponding to the selection of the clutch.
When the backward clutch 20 is put into operation, the forward one-way clutch 42 is freed as is the case of Fig. 3a, as~shown in Fig. 3b, so that the inner and outer wheels 43b and 43a of the backward one-way clutch 43 rotate unitarily with each other to drive the speed-changing shaft 4 at a predetermined backward speed.
In the event that the vehicle starts to move naturally when it is parked on a slope, the backward one-way clutch 43 is freed as shown in Fig. 3c, as is the case of Fig. 3a, but the inner wheel 42b and the outer wheel 42a are locked to each other because the the inner wheel 42b of tbe forward one-way clutch 42 rotates counter-clockwise together with the speed-changing shaft 4 to realize such a state that the outer wheel 42a makes a clockwise rotation relatively to the inner wheel 42b. Therefore, the torque of the speed-changing shaft 4 is transmitted to the engine 1 through the input shaft 3 to achieve the engine braking effect thereby to automatically stop the natural running of the vehicle.
When the automobile is parked on a slope with its front side directed toward the higher side of the slope, the outer wheel 43a of the backward one-way clutch 43 tends to make a counter~clockwise rotation relatively to the speed-changing shaft 4 as shown in Fig. 3d, so that the inner wheel 43b and outer wheel 43a are locked to each other so that the torque of the speed-changing gear 4 is transmitted throgh the backward speed-changing gear 14, baclward idle gear 15 and the backward counter gear 11 to the counter shaft 8 and further to the engine through the counter gear 12a and the input gear 3a thereby to effect the engine braXing.
In the second embodiment of the invention shown -in Fig. 4, the forward one-way clutch 42 operates in the same manner as the described first embodiment. As to the backward one-way clutch 48, the outer wheel 48b fitting the backward counter gear 45 makes a counter-clockwise rotation relatively to the inner wheel 48a fitting the counter shaft-8 in the state of forward driving of the of the vehicle ~Fig. 5a) and in the state in whlch the vehicle is parked with its engine stopped on a descending slope (Fig. 5c).~ In this state, the inner wheel 48a 11~3~33 and the outer wheel 48b are freed. However, these wheels 48a,48b are made torotate as a unit with each other as the backward clutch 47 is put into operation.
Furthermore, when the vehicle is parked on an ascending slope, the outer wheel 48b tends to rotate clockwise to make a clockwise rotation relatively to the inner wheel 48a as shown in Fig. 5d.
Thus, the one-way clutch 48 is locked so that the torque of the speed-changing shaft 4 is transmitted to the engine 1 through the counter shaft 8 to efect "
the engine braking. In this state. it is also possible to start the engine by manually pushing the vehicle forwardly.
Thus, according to the invention, the engine braking effect is obtained to prevent the vehicle from automatically running in both of ~orward and back ward directions when the vehicle is parked on a slope for a long time, irrespective of a pressure drop in the hydraulic clutches in the transmission system incor-porating hydraulic clutches and irrespective of the "OFF" state of mechanical clutch in the transmission system incorporating mechanical clutches, so as to:~
assist~the parking brake in parking the vehicle safely.
In addition, the speed-changing transmiss~on device of the invention permits the-engine to be started .
.
.
, 1~3~L83 by a manual pushing of the vehicle in ~he event of an exhaustion of the battery.
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VEHICLES
Background of the Invention:
Field of the Invention The present invention relates to a speed-changing transmission device for vehicles and, more particularly, to an improvement in a speed-changing transmission device for vehicles, of the type having a counter shaft adapted to be driven by an input shaft which in turn is driven by an engine,.a transmission shaft for driving a wheel axle or the like, the counter shaft and the speed-changing shaft being connected to each other through a forward transmission gear system and also through a backward transmission gear system, and clutches disposed in respective transmission paths and adapted to be selectively used to effect the changing of the speed.
Description of the Prior Art In the conventional speed-changing transmission device for vehicles, when, for example, the pressure of the oilifor operating the clutch for:changing the speed is lowered due to the stop of the engine during parking, the clutch takes the "off" state to disconnect the driving wheel axle or the like from the engine. In this state, it is not possible to utilize the engine - 1 - ~"~
i~
., , ~ . , .
, braking effect.whlch is quite useful particularly when the vehicle is parked on a steel slope. In such a case, if the parking brake is opera-ted insufficiently, the vehicle will-naturally start dangerously. It is also to be pointed out that, in the event of an:
excessive discharge~of the battery, it is not possible to start the engine by pushing the vehicle manually, because the driving..wheel axle is disconnected from the engine.
Summary of the Invention It is, thereEore, an ohject of the invention to provide a speed-changing transmission device in which, even when the clutch for the speed changing becomes inoperative or to take the lloff" state during parking, the direct connectio~..is:maintàined between~the engine and the driving wheel axle or the like to ensure the engine braking effect during parking.
According to the invention, the above-stated object is achieved by a speed-changing transmission device having the following featuresO
Namely, the invention provides a speed-changing transmission device comprising: a speed-changing gear for transmitting the torque to the driving wheel axle or the like and mounted.at the rear side of an.inputs shaft drivenl.by the engine coaxially with`the input shaft, 3:~83 a counter shaft mounted in parallel with the speed-changing shaft and carrying a counter gear always meshing with an input gear:on the input shaft, a forward speed changing-gear system provided on the speed-changing shaft and:the counter shaft, the forward speed changing gear system including a forward speed-changing gear and a forward counter gear which are meshing with each other and adapted to transmit the rotation of the counter shaft to the speed-changing shaft at a speed reduced as compared with the speed of the input shaft or in the reverse direction to the rotation of the input shaft, a backward speed-changing gear system provided on the speed-changing shaft~and:~he counter shaft, the backward speed--changing gear system including a backward speed changing gear, a backward idle gear and a backward counter gear, a clutch disposed between the input shaft and the speed-changing shaft and clutches disposed in the transmission paths provided by respective speed-changing gear systems between the input shaft and the speed-changing shaft, the.. clutches being usabla selectively, a one-way clutch for forward driving disposed between the input shaft and the speed-changing shaft, and a one-way clutch for backward driving disposed between the speed-changing shaft and the backward speed-changing gear system or between the ~ ~3~83 counter shaft and the backward speed-changing gear system.
Brief Descript-ion of the Drawings The invention is illustrated by way of example in the accompanying drawings wherein:
Fig. 1 is a vertical sectional side elevational view of the front portion of mission case of a powered agricultural machine to which a device of a first embodiment of the invention is applied;
Fig. 2 illustrates the power transmission system of the embodiment shown in Fig. 1;
Figs. 3A to 3D are illustrations explanatory of the operation of forward and backward one-way clutches in the embodiment shown in Fig. l;
More particularly:
Fig. 3A views show state of engine forward driving, respective views, forward and backward;
Fig. 3B views show state of engine backward driving, respective views, forward and backward;
Fig. 3C views show state of engine stopping forward driving: rotates on its own axis, respective views, forward and backward;
Fig. 3D views show state of engine stopping backward driving: rotates on its own axis, respective views, forward and backward;
Fig. 4 illustrates the power transmission system of a second embodiment of the invention; and Figs. 5A to 5D are illustrations explanatory of the operation of forward and backward one-way clutches in the , .
.' `~ ' ' : -'-. ~
embodiment shown in Fig. 4.
More particularly:
Fig. 5A views show state of engine forward driving,respective views, forward and backward;
Fig~ 5B views show state of engine backward driving, respective views, forward and backward;
Fig. 5C views show state of engine stopping forward driving: rotates on its own axis, respective views, forward and backward;
Fig. 5D views show state of engine stopping backward driving: rotates on its own axis, respective views, forward and backward;
Description of the Preferred Embodiments:
Hereinafter, preferred embodiments of the invention applied to a powered agricultural machine will be described with reference to the accompanying drawings.
As will be seen from Fig. 1 showing a vertical section, as well as from Fig. 2 showing the power transmission system schematically, an engine 1 has a -4a-:, ' ' ' '' crank shaft to which connected is an input shaft 3 through a maln clutch 2. A speed-changing shaft 4 is suppo~ted at its front end by a bearing 5 and is disposed behind the input shaft 3. The rear end o the speed-changing shaft 4 is supported by a mission .
case 7 through a medium of a bearing 6. A counter shaft 8 is mounted in parallel with the speed-changing shaft 4 and supported by bearings 9,10 on the mission case 7. A counter gear 11 of small diameter for backward driving and counter gears 12b,12c for forward driving having different diameters are carried by the counter shaft 8. ~ speed-changing gear 14 for backward driving, rotatably mounted on the speed-changing shaft through a bearing 13 meshes through an idle gear 15 for backward driving with a counter gear 11 for backward driving to constitute a backward speed-changing gear system.
Speed changing gears 18b,18c for forward driving, rotatably mounted on the speed-changing shaft 4 through bear-ngs 16,17, engage with counter gears 12b, 12c for forward driving, while anuinput gear 3a of a smàll diameter formed at the rear portion of the input shaft 3 meshes with a counter gear 12a of a large diameter to constitute a forward speed-changing gear system.
A clutch 20 for hackward driving is connected '~
between the backward speed-changing gear 14 and the speed-changing shaft 4. Also, provided are clutches 21a,21b,21c for forward driving so as to connect speed-changing gears 18b,18c to the clutch shaft 4.
These clutches are adapted be operated selectively.
A second speed-changing shaft 22 is connected to the speed-changing shaft 4 through a gear as shown in Fig. 2. A group 23 of shift gears slidable on~y in the axial direction along the second speed-changing shaft 22 is adapted to be brought into engagement with a group 25 of second counter gears selectively by means of a mechanical speed-changing device 26. A
drive pinion shaft 28 drivingly connected to the second speed-changing shaft 22 through a clutch 27 is adapted to drive left and right rear driving wheels 31, 31 of the vehicle through a rear wheel differential gear device 29. The rear wheels 31 are provided with respective brakes. .:::
The construction of the backward clutch 20 and the forward clutches 21a to 21c will be explained herein-under with specific reference to the clutch 21a for the forward driving by way of example. The clutch 21a has a clutch housing 32 fitted to the speed-changing shaft 4 and accomodating in an oil-tight manner a piston 33 which is biased in the d~sengag~n~ diæection~by means of .. , .. .- . ,. . . ~ . ~
~3~3 a spring 33. A friction disc 35 fits in the clutch housiny 32 slidably only in the axial direction, while a friction disc 36 is fitted to a hub of an input gear 3a slidably only in the axial direction. A
working oil deliv~red by an oil pump 37 is introduced into a speed-changing switching valve 39 through a relay cylinder 38 fitting the rear end of the speed-changing shaft 4. As the driver manipulates a speed-changing lever 40, the spool 41 of the switching valve 39 is slided in the axial direction to distribute the oil selectively from an oil passage 7a in the mission case 7 and an oil passage 38a in the relay cylinder 38 via the oil passages a,b... of the clutch housings of clutches selected by the speed-changing lever 40. For instanee, assuming here that the pressurized oil is supplied to the rear side of a piston 34 via the oil passage a, the piston 34 makes the frictional discs 35,36 engage with eaeh other thereby to eonnect the input gear 3a to the speed-ehanging shaft 4.
Thus, the power transmission provided by the mutual engagement between the forward eounter gear 12e and the forw-rd speed-changing gear 18c, caused by the engaging operation of the forward clutch 21c, provides a rotation speed of first forward speed (V1),which is the lowest of the forward speeds, to the speed-changing shaft 4. Slmilarly, a Eorward second speed V2 is given throuyh the mutual engagement of the forward counter gear 12b and the forward speed-changing gear 18b as the forward cluth 21b is brought into "ON" state, and the highest forward speed V3 is imparted to the speed-changing shaft 4 as the forward clutch 21a is put into operation, by a direct connection. Also, as the backward clutch 20 is put into operation, a backward first speed R1 is imparted to the speed-changing shaft 4 through the backward counter gear 11, backward idle gear 15 and the backward speed-changing gear 14.
The unput gear 3a is coupled to the speed-changing gear 4 through a one-way clutch 42 which can deliver to the input shaft 3 only the forward driving power from the speed-changing shaft 4. Namely, as shown in Fig. 3a, an outer wheel 42a fitted around the input gear 3a is adapted to rotate counter-clockwise as viewed from the rear side. This outer wheel 42a makes a counter-clockwise rotation relati~ely to an inner wheel 42b fitting the speed-changing shaft 4 which rotates in the same direction as the input shaft 3 at the forward first or second speeds Vl,V2 which is lower than the speed of the input shaft 3. Therefore, the input gear 3a and the speed-changing shaft 4 rotate 3~3 freely from each other. The outer wheel 42a making a counter-clockwise rotation relatively to the inner wheel 42b and the input gear 3a can rotate freely from each other also when the speed-changing shaft 4 makes a clockwise rotation as shown in Fig. 3b. However, when in~the state shown in Fig. 3c in which the inner wheel 42b makes a counter-clockwise rotation relatively to the outer wheel 42a, the speed-changing gear 4 and the input gear 3a rotate as a unit with each other by the action of the one-way clutch 42.
The backward speed-changing gear 14 is connected to the speed-changing shaft 4 through a one-way clutch 43 which can deliver to the backward speed-changing gear 14 only the backward driving power from the speed-changing shaft 4. Namely, an outer wheel 43a fits to the speed-changing gear 14 which is adapted to rotate only in the clockwise direction as viewed from the rear side as shown in Fig. 3a. This outer wheel 43a rotates freely from ans inner wheel 43b which rotates counter-clockwise at the forward first or second speed Vl,V2. However, in the state shown in Fig. 3d in which the inner ring 43b makes a clockwise rotation reatively to the outer wheel 43a as mentioned later, the speed-changing gear 14 and the speed-changing shaft 4 rotate as a unit with each other by the action of ~3~3 the one-way clutch 43.
In another embodiment shown in Fig. 4, a backward speed-changing gear 44 is fitted to the speed-changing shaft 4, while a backward counter gear 45 for engagement with the backward idle gear 15 is rotatably carried by the counter shaft 8 through a bearing 46.
The backward counter gear 45 is connected to the cou~ter shaft 8 through a backward clutch 47 having a clutch housing fitting the counter shaft 8. Also, a one-way clutch 48 for backward driving is dis~osed to provide a connection between the backward clutch 48 and the counter shaft 8. The one-way clutch 48 is of the type capable of delivering to the counter shaft 8 only the forward driving power from the backward counter gear 45.
Namely, when the inner whhel'48a'fit~ing-to'-the counter shaft 8 rotating clockwise as viewed from the rear side makes a clockwise rotation relatively to the outer wheel 48b fitting to the backward counter gear 45 as shown in ~ig. 5a, the inner wheel 48a and the outer wheel 48b can rotate independently of each other.
However,'in the state shown in, for example, Fig. 5d in which the outér wheel 48b makes a clockwise rotation relatively to the inner wheel'48a, the backward counter gear 45 and the counter shaft 8 rotate'as a unit with 3~3 each other by the action of the one-way clutch 48.
In the powered agricull:ual machine as shown in the drawings, the torque of the counter gear 12a is adapted to be transmitted to a power shaft 51 through a PTO clutch 49 and a PTO gear unit 50.
In the illustrated and described embodlments, the forward speed changing gear system and the backward speed-changing gear system are adapted to be operated by means o~ hydraulically actuated clutches. The invnetion, however, can be equally applied to the systems having mechanically actuated clutches.
The operation of the speed-changing transmission device of the invention can be achieved even when the forward clutch 2la is eliminated.
In the speed-changing transmission device of the first:embodiment o~-the invention, as;thé orward clutches 21c,21b are operated selectlvely, the speed-changing shaft rotates at a forward first or second speed Vl,V2 which is higher than that of the input shaft 3.
Therefore, the inout gear 3a, rotating counter-clockwise relatively to the speed-changing shaft 4 as viewed from the rear side can rotate freely. As to the back-ward onw-way clutch 43, the backward speed-changing gear 14 rotating clockwise relatively to the speed-changing 3~i33 shaft 4 can be rotated freely. Therefore, thetorque of the input shaft 3 is transmitted through the forward clutch 21c or 21b to the speed-changing gear 4 to drive the latter at a reduced speed of forward first or second speeds Vl,V2 corresponding to the selection of the clutch.
When the backward clutch 20 is put into operation, the forward one-way clutch 42 is freed as is the case of Fig. 3a, as~shown in Fig. 3b, so that the inner and outer wheels 43b and 43a of the backward one-way clutch 43 rotate unitarily with each other to drive the speed-changing shaft 4 at a predetermined backward speed.
In the event that the vehicle starts to move naturally when it is parked on a slope, the backward one-way clutch 43 is freed as shown in Fig. 3c, as is the case of Fig. 3a, but the inner wheel 42b and the outer wheel 42a are locked to each other because the the inner wheel 42b of tbe forward one-way clutch 42 rotates counter-clockwise together with the speed-changing shaft 4 to realize such a state that the outer wheel 42a makes a clockwise rotation relatively to the inner wheel 42b. Therefore, the torque of the speed-changing shaft 4 is transmitted to the engine 1 through the input shaft 3 to achieve the engine braking effect thereby to automatically stop the natural running of the vehicle.
When the automobile is parked on a slope with its front side directed toward the higher side of the slope, the outer wheel 43a of the backward one-way clutch 43 tends to make a counter~clockwise rotation relatively to the speed-changing shaft 4 as shown in Fig. 3d, so that the inner wheel 43b and outer wheel 43a are locked to each other so that the torque of the speed-changing gear 4 is transmitted throgh the backward speed-changing gear 14, baclward idle gear 15 and the backward counter gear 11 to the counter shaft 8 and further to the engine through the counter gear 12a and the input gear 3a thereby to effect the engine braXing.
In the second embodiment of the invention shown -in Fig. 4, the forward one-way clutch 42 operates in the same manner as the described first embodiment. As to the backward one-way clutch 48, the outer wheel 48b fitting the backward counter gear 45 makes a counter-clockwise rotation relatively to the inner wheel 48a fitting the counter shaft-8 in the state of forward driving of the of the vehicle ~Fig. 5a) and in the state in whlch the vehicle is parked with its engine stopped on a descending slope (Fig. 5c).~ In this state, the inner wheel 48a 11~3~33 and the outer wheel 48b are freed. However, these wheels 48a,48b are made torotate as a unit with each other as the backward clutch 47 is put into operation.
Furthermore, when the vehicle is parked on an ascending slope, the outer wheel 48b tends to rotate clockwise to make a clockwise rotation relatively to the inner wheel 48a as shown in Fig. 5d.
Thus, the one-way clutch 48 is locked so that the torque of the speed-changing shaft 4 is transmitted to the engine 1 through the counter shaft 8 to efect "
the engine braking. In this state. it is also possible to start the engine by manually pushing the vehicle forwardly.
Thus, according to the invention, the engine braking effect is obtained to prevent the vehicle from automatically running in both of ~orward and back ward directions when the vehicle is parked on a slope for a long time, irrespective of a pressure drop in the hydraulic clutches in the transmission system incor-porating hydraulic clutches and irrespective of the "OFF" state of mechanical clutch in the transmission system incorporating mechanical clutches, so as to:~
assist~the parking brake in parking the vehicle safely.
In addition, the speed-changing transmiss~on device of the invention permits the-engine to be started .
.
.
, 1~3~L83 by a manual pushing of the vehicle in ~he event of an exhaustion of the battery.
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Claims (3)
1. A speed-changing transmission device for vehicles comprising: a speed-changing shaft 4 for transmitting driving power to rear wheels 31,31 and mounted at the rear side of an input shaft 3-driven by an engine 1 coaxially with said input shaft 3; a counter shaft 8 mounted in parallel with said speed-changing shaft 4 and carrying a counter gear 12a always meshing with an input gear 3a provided on said input shaft 3; a forward speed-changing gear system provided between said speed-changing shaft 4 and said counter shaft 8 and including a forward speed-changing gear and a forward counter gear meshing with each other so as to transmit the rotation of said counter shaft 8 to said speed-changing shaft 4 at a speed reduced as compared with the speed of said input shaft or in the reverse direction to the direction of rotation of the input shaft 3; a backward speed-changing gear system provided between said speed-changing shaft 4 and said counter shaft 8 and including a backward speed-changing gear, backward idle gear and a backward counter gear; clutches disposed between said input shaft 3 and said speed-changing shaft 4 and in the power transmission paths formed by respective speed-changing gear systems and adapted to be operated selectively; a forward one-way clutch disposed between said input shaft 3 and said speed-changing shaft 4; and a backward one-way clutch disposed between said speed-changing shaft and said backward speed changing gear system or between said counter shaft 8 and said backward speed-changing gear system.
2. A speed-changing transmission device as claimed in claim 1, wherein said backward speed-changing gear system includes a backward speed-changing gear 14 rotatably mounted on said speed-changing shaft 4, a backward counter gear 11 fitting said counter shaft 8 , a backward idle gear 15 meshing with both of backward speed-changing gear and backward counter gear, and a backward one-way clutch disposed between said speed changing shaft 4 and said backward speed changing gear 14.
3. A speed-changing transmission device as claimed in claim 1, wherein said backward speed-changing gear system includes a backward speed changing gear 44 fitted to said speed-changing shaft 4, a backward counter gear 45 rotatably carried by said counter shaft 8, a backward idle gear 15 meshing with both of said backward speed changing gear 44 and said backward counter gear 45, and a backward one-way clutch disposed between said counter shaft 8 and said backward counter gear 45.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000373215A CA1143183A (en) | 1981-03-17 | 1981-03-17 | Speed-changing transmission device for vehicles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000373215A CA1143183A (en) | 1981-03-17 | 1981-03-17 | Speed-changing transmission device for vehicles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1143183A true CA1143183A (en) | 1983-03-22 |
Family
ID=4119472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000373215A Expired CA1143183A (en) | 1981-03-17 | 1981-03-17 | Speed-changing transmission device for vehicles |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1143183A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114829810A (en) * | 2019-10-29 | 2022-07-29 | 印第安国际机车有限公司 | Reverse gear system for vehicle |
-
1981
- 1981-03-17 CA CA000373215A patent/CA1143183A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114829810A (en) * | 2019-10-29 | 2022-07-29 | 印第安国际机车有限公司 | Reverse gear system for vehicle |
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