JP2000213625A - Transmission gear for small-sized vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a creep phenomenon, enable a transmission to lightly perform speed changed operation, and suppress a slip of a hydraulic transmission means to improve the transmission efficiency in a transmission gear for small vehicles, which is provided with the hydraulic transmission means comprising a hydraulic torque converter in a transmission path between an engine and a multistage transmission. SOLUTION: In a transmission gear in which the crankshaft 2 of an engine and the input shaft of a multistage transmission M are connected together through a hydraulic transmission means T, a speed change clutch Cc which is in series with the hydraulic transmission means T, is interposed between the crankshaft 2 of the engine and the multistage transmission. Further, a lock-up clutch Lc is interposed between a pump impeller 50 and a turbine wheel 51 of the hydraulic transmission means T.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fluid transmission means for connecting a crankshaft of an engine and an input shaft of a multi-stage transmission with a pump impeller connected to the engine and a turbine impeller connected to the multi-stage transmission, that is, a fluid transmission means. The present invention relates to a transmission for a small vehicle connected via a torque converter or a fluid coupling.

[0002]

2. Description of the Related Art Such a transmission for a small vehicle is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-69163.
Already known.

[0003]

In such a conventional transmission for a small vehicle, as disclosed in the above-mentioned publication, the crankshaft of the engine and the input shaft of the multi-stage transmission are connected only through the torque converter. In connection with this, torque shock at the time of starting or shifting is absorbed by the slipping action of the torque converter.

[0004] However, although the torque converter and the fluid coupling have a slipping function, they transmit torque to some extent as long as power is input from the engine. Therefore, in the conventional device, the transmission is switched from the neutral position to the low position. At the start, a creep phenomenon occurs in which power is transmitted to the drive wheels of the vehicle to some extent even when the engine is idling. Further, during traveling, since the friction caused by the transmission torque always acts on the switching sliding portion of the transmission, there are disadvantages such as a large switching resistance of the transmission and a large shift operation load.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to eliminate the creep phenomenon and to perform a speedy shift operation of a transmission. It is an object of the present invention to provide a transmission for a small-sized vehicle, wherein transmission is improved while suppressing transmission.

[0006]

In order to achieve the above object, the present invention relates to a method of connecting a crankshaft of an engine and an input shaft of a multi-stage transmission to a pump impeller connected to the engine and a multi-stage transmission. In a transmission for a small vehicle, which is connected through a fluid transmission means having a turbine impeller, a transmission clutch in series with the fluid transmission means is interposed between a crankshaft of an engine and an input shaft of a multi-stage transmission, A first feature is that a lock-up clutch is provided between the pump impeller and the turbine impeller of the fluid transmission means so that the two impellers can be directly connected to each other.

[0007] The fluid transmission means corresponds to a torque converter T in each embodiment of the present invention described later.

According to the first feature, when the engine is idling, the transmission clutch is controlled to be in the off state even when the transmission is in the low position, so that power transmission to the transmission clutch and thereafter is performed regardless of the presence of the fluid transmission means. To prevent creep. Further, at the time of a gearshift operation, by first controlling the gearshift clutch to the off state, the gearshift can be performed lightly without a torque shock by setting the transmission to a no-load state regardless of the presence of the fluid transmission means. .

In addition, during cruising, if the lock-up clutch is controlled to the ON state, the pump impeller and the turbine impeller are directly connected to each other, so that slippage between the two impellers can be eliminated and power loss can be prevented.

In addition to the above-mentioned features, the present invention provides a lock-up clutch which is connected to a pump impeller and surrounds a turbine impeller, and a pump extension connected to a tip of the pump extension. A pressure receiving plate defining a hydraulic chamber communicating with an oil chamber between the pump impeller and the turbine impeller, a pressure plate opposed to the pressure receiving plate and biased toward the pressure receiving plate by the hydraulic pressure of the hydraulic chamber; An annular friction clutch plate interposed between the pressure receiving plate and the pressure plate and connected to the turbine impeller; and first and second friction clutch plates provided on the pressure plate and the pressure receiving plate on the inner peripheral side of the friction clutch plate, respectively. A valve hole, a control valve provided on the pressure plate to close the first valve hole,
The retracted position is fitted in the first and second valve holes to allow the control valve to close, the inner peripheral side of the friction clutch plate is opened to the outside of the second valve hole, and the second valve hole is closed. A second feature of the present invention is that it comprises a control rod capable of moving between forward positions for opening the control valve to communicate the inner peripheral side of the friction clutch plate with the hydraulic chamber, and operating means for operating the control rod. And

The operating means corresponds to a lock-up clutch operating shaft 86 in a first embodiment of the present invention described later.

According to the second feature, when the control rod is operated to the retracted position, the pressure plate sandwiches the friction clutch plate between the pressure receiving plate and the pressure receiving plate by the hydraulic pressure transmitted from the fluid transmission means to the hydraulic chamber. When the lock-up clutch can be turned on and the control rod is operated to the forward position, the oil pressure in the hydraulic chamber acts on both sides of the pressure plate, losing the clamping force against the friction clutch plate, and the lock-up clutch is released. It can be turned off. In this off state, the control rod closes the second valve hole, thereby preventing unnecessary leakage of hydraulic pressure from the hydraulic chamber.

Further, the present invention, in addition to the first or second feature, further comprises a one-way clutch between the crankshaft and the turbine impeller which is turned on when the turbine impeller receives a reverse load torque. This is the third feature.

According to the third feature, when the engine is braked during running, the one-way clutch is turned on by applying a reverse load torque to the turbine impeller, so that the turbine impeller and the crankshaft are directly connected to each other. As a result, the reverse load torque is transmitted to the crankshaft without passing through the fluid transmission means, and a good engine braking effect can be obtained.

Further, in the present invention, in addition to the first feature, the lock-up clutch is configured to be automatically operated when the rotation speed of the pump impeller becomes equal to or higher than a predetermined value, and is configured to be dependent on the rotation speed of the pump impeller. This is the fourth feature.

According to the fourth feature, when the rotation speed of the pump impeller becomes equal to or higher than the predetermined value, the pump impeller and the turbine impeller of the fluid transmission means can be automatically directly connected.

Further, according to the present invention, in addition to the fourth feature, a lock-up clutch is connected to a pump extension connected to the pump impeller and surrounding the turbine impeller, and is coupled to a tip of the pump extension. A pressure receiving plate defining a hydraulic chamber communicating with an oil chamber between the pump impeller and the turbine impeller in the pump extension, a pressure plate opposed to the pressure receiving plate so as to be able to advance and retreat, and a pressure plate between the pressure receiving plate and the pressure plate. An annular friction clutch plate interposed and connected to the turbine impeller; a return spring for urging the pressure plate in a direction to retract the pressure plate with respect to the pressure receiving plate; When the rotational speed of the pump impeller exceeds a predetermined value, the pressurizing plate cooperates with the pressure receiving plate to press the friction clutch plate by the centrifugal oil pressure in the hydraulic chamber that rises accordingly when the pump impeller rotation speed exceeds a predetermined value. What I did The fifth feature.

According to the fifth feature, automatic control of the lock-up clutch depending on the rotation speed of the pump impeller can be easily performed.

Further, according to the present invention, in addition to the first feature, the lock-up clutch is configured to operate automatically when the rotation speed of the turbine impeller exceeds a predetermined value. This is the sixth feature.

According to the sixth feature, when the rotation speed of the turbine impeller becomes equal to or more than the predetermined value, the pump impeller and the turbine impeller of the fluid transmission means can be automatically directly connected.

Furthermore, in the present invention, in addition to the sixth feature, a lock-up clutch is connected to a turbine impeller, and a hydraulic chamber is slidably fitted in a cylinder hole of the clutch cylinder. A pressure piston to be defined, a piston return spring for urging the pressure piston toward the hydraulic chamber, a means for introducing oil into the hydraulic chamber, and a friction engagement means provided between the clutch cylinder and the pump impeller. When the rotation speed of the turbine impeller exceeds a predetermined value, the pressurizing piston operates the frictional engagement means by the centrifugal oil pressure in the hydraulic chamber which rises accordingly to connect the clutch cylinder and the pump impeller. The frictional engagement means is a driving friction clutch plate 110 and a driven friction clutch plate 11 in a third embodiment of the present invention described later. And corresponds to the transmission claw 112, also means for introducing said oil inlet port 11 in the embodiment
Corresponds to 7.

According to the seventh aspect, automatic control of the lock-up clutch depending on the turbine impeller rotation speed can be easily performed.

Further, in addition to the seventh feature, in the present invention, a release hole for opening the outer peripheral side of the hydraulic chamber to the outside and a release hole when the rotational speed of the clutch cylinder is less than a predetermined value are provided in the clutch cylinder. An eighth feature is that a centrifugal valve is provided that opens and closes the escape hole when the value exceeds a predetermined value.

According to the eighth feature, when the rotational speed of the clutch cylinder is less than the predetermined rotational speed, the residual pressure of the hydraulic chamber is released from the relief hole by opening the centrifugal valve, thereby improving the off performance of the lock-up clutch. Also, foreign matter such as chips in the hydraulic chamber can be discharged from the escape hole together with the oil,
At a predetermined rotational speed or higher, the hydraulic chamber can be boosted by closing the centrifugal valve, and the operation of the lock-up clutch is not hindered.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 12 show a first embodiment of the present invention. FIG. 1 is a side view of a motorcycle to which the present invention is applied.
2 is a longitudinal sectional view of a power unit mounted on the motorcycle, FIG. 3 is an enlarged longitudinal sectional view of a transmission in the power unit, FIG. 4 is a sectional view taken along line 4-4 of FIG. 3, and FIG.
6 is a side view of the transmission, FIG. 7 is an enlarged view showing the outlet valve of the transmission clutch in FIG. 3 in a closed state,
8 is an enlarged view showing the outlet valve in an open state, FIG. 9 is a sectional view taken along line 9-9 of FIG. 3, FIG. 10 is a sectional view taken along line 10-10 of FIG.
FIG. 11 is an enlarged view showing the control valve of the lock-up clutch in FIG. 3 in a closed state, and FIG. 12 is an enlarged view showing the control valve in an open state. FIG. 13 shows a second embodiment of the present invention.
FIG. 14 is a sectional view corresponding to FIG. 3, showing a third embodiment of the present invention. 15 to 17 show a fourth embodiment of the present invention. FIG. 15 is a side view of a four-wheeled buggy to which the present invention is applied, and FIG. 16 is a longitudinal sectional view of a power unit part of the four-wheeled buggy. FIG. 17 is a plan view and FIG. 17 is an enlarged vertical sectional view of the power unit transmission.

First, a description will be given of the first embodiment of the present invention shown in FIGS.

In FIG. 1, a motorcycle Vm has a saddle Sm mounted on an upper portion of a body frame Fm supporting a front wheel Wf and a rear wheel Wr, and a power unit P mounted on a lower portion thereof. Tank T
fm is provided.

As shown in FIGS. 1 and 2, the power unit P is constructed by integrating an engine E and a multi-stage transmission M. The engine E includes a pair of left and right ball bearings 3, 3 '
And a piston 7 slidably fitted in a cylinder bore 5a of the cylinder block 5 and connected to the crankshaft 2 via a connecting rod 6. It is arranged in the left-right direction of the motorcycle Vm. The cylinder block 5 has
A cylinder head 4 defining a combustion chamber 4a is joined to a top surface of the piston 7, and an intake and exhaust valve (not shown) for opening and closing an intake and exhaust port connected to the combustion chamber 4a is connected to the cylinder head 4. And a cam shaft 9 for opening and closing them. The camshaft 9 is rotatably supported by the cylinder head 4 in parallel with the crankshaft 2.

A transmission case 8 is provided in the crankcase 1.
The input shaft 10 and the output shaft 11 of the multi-stage transmission M, which are arranged in parallel with the crankshaft 2, are respectively ball bearings 12, 12 ′, 13 by the left and right side walls of the transmission case 8. , 13 ', and over the input shaft 10 and the output shaft 11, from the left side in FIG. 2, the first gear train G1, the second gear train G2, the third gear train G3, and the fourth gear train. G4 is provided. When the driven gear G2b of the second speed gear train G2 and the drive gear G3a of the third speed gear train G3 also serve as a shift gear, and both shift gears G2b and G3a are in the neutral position,
The transmission M is in the neutral state and the shift gear G2b
Moves left or right in the figure, the first gear train G1 or the third gear train G3 is established, and when the shift gear G3a moves left or right, the second gear train G2 or the fourth gear train G4 is moved. Is to be established. The shift gears G2b, G3a
Is operated by a known pedal type or other manual type change device (not shown).

The right end of the crankshaft 2 and the right end of the input shaft 10 of the transmission M are connected to a transmission clutch C connected in series with each other outside the crankcase 1 and the transmission case 8.
c, the torque converter T and the primary reduction gear 14 are connected to each other. At this time, in particular, the transmission clutch Cc,
Drive gear 1 of torque converter T and primary reduction gear 14
Reference numeral 4a is mounted on the crankshaft 2 in the order of the drive gear 14a, the torque converter T, and the transmission clutch Cc from the right side wall of the crankcase 1 outward. Then, a right side cover 15 a covering these is joined to the right end surfaces of the crankcase 1 and the transmission case 8.

At the left end of the crankshaft 2, a rotor 17 of a generator 16 is fixed, and its stator 18 is
6 and is attached to the left side cover 15b joined to the left end surface of the crankcase 1. In the crankcase 1 and the cylinder block 5, a series of timing transmission chambers 90 are formed on the left side wall opposite to the torque converter T and the primary reduction gear 14. A timing transmission 91 for transmitting to the camshaft 9 at a reduced speed by half is accommodated. In this way, the primary speed reducer 14, the torque converter T and the transmission clutch Cc, the timing transmission 91 and the generator 16 are arranged at both ends of the crankshaft 2 inside the crankcase 1, that is, with the crank chamber interposed therebetween.

As shown in FIGS. 2 and 3, the crankshaft 2
An upstream supply oil passage 27a opening at the right end face thereof, and a downstream supply oil passage 27b communicating with a needle bearing 49 on the outer periphery of a crankpin supporting the large end of the connecting rod 6.
An orifice 48 that directly connects the two oil passages 27a and 27b, a first inflow hole 43a that extends radially from the upstream supply oil passage 27a toward the speed change clutch Cc, and a first inflow hole 43a that extends from the upstream supply oil passage 27a toward the torque converter T. A second inflow hole 43b extending in the radial direction and an outflow hole 45 extending in the radial direction from the downstream supply oil passage 27b toward the torque converter T are provided. The oil pump 44 driven by the engine E pumps the oil sucked from the oil reservoir 46 through the oil passage 27 formed in the right side cover 15a into the upstream supply oil passage 27a. The oil reservoir 46 is formed at the bottom of the crankcase 1, the transmission case 8, and the right side cover 15a.

To the left end of the output shaft 11 of the transmission M, a chain type final reduction gear 19 for driving a rear wheel (not shown) of the motorcycle outside the transmission case 8 is connected.

2 and 3, the transmission clutch Cc
Is a cylindrical clutch casing 20 having an end wall 20a at one end and a boss 20b spline-coupled to the crankshaft 2 at the center, and is slidable on the outer periphery of the boss 20b within the clutch casing 20. A pressure plate 21 which is spline-fitted to the pressure plate; a pressure receiving plate 22 which is fixed to the open end of the clutch casing 20 in an oil-tight manner;
And a ring-shaped friction clutch plate 23 interposed between the pressure clutch plate 1 and the pressure receiving plate 22, and a transmission plate 24 of a pump impeller 50 described later is spline-engaged with the inner periphery of the friction clutch plate 23 (FIG. 4). reference).

The pressure plate 21 defines a hydraulic chamber 25 between the end wall 20a and the peripheral wall of the clutch casing 20. The hydraulic chamber 25 is provided with a boss 20b of the clutch casing 20.
Is connected to the first inflow hole 43a of the crankshaft 2 via an inlet valve 26 provided on the crankshaft 2 and is opened outside the clutch casing 20 via an outlet valve 28 provided on the outer peripheral portion of the end wall 20a. Has become.

As shown in FIGS. 3 and 4, a plurality of bosses 20b (3 in the illustrated example) extending parallel to the crankshaft 2 are provided.
) And the first inflow hole 4 through each of the valve holes 29.
A plurality of through-holes 30 extending from the hydraulic valve 3a to the hydraulic chamber 25 are formed.
6 are slidably fitted. And these inlet valves 26
3 occupies the right movement position in FIG. 3 (upper half of FIG. 3), opens the through hole 30 and occupies the left movement position (see lower half of FIG. 3), closes the through hole 30. It has become. In order to ensure the communication between the through hole 30 of the boss 20b and the first inflow hole 43a of the crankshaft 2, the crankshaft 2 and the boss 20
It is effective to cut off some of the teeth of the spline portion that fits each other in b.

The end wall 20a of the clutch casing 20
A plurality (three in the illustrated example) of outlet holes 32 are formed at equal intervals in the circumferential direction of the
One end of an outlet valve 28 composed of a reed valve, which can be opened and closed on the hydraulic chamber 25 side, is caulked to the end wall 20a.

A guide collar 33 communicating with each outlet hole 32 is fixed to the end wall 20a, and the valve-opening rod 31 is slidably fitted to each guide collar 33. The valve-opening rod 31 has a groove 31a extending in the axial direction on the outer periphery thereof. When the valve-opening rod 31 occupies the right-moving position in FIG. 3 (see the upper half of FIG. Is allowed to close the outlet hole 32 due to the elastic force of the left side (see the lower half of FIG. 3 and FIG. 8), and the outlet valve 28 is connected to the hydraulic chamber 25.
The outlet hole 32 is opened by bending inward.

At the outer ends of the inlet valve 26 and the valve rod 31,
A common valve actuation plate 34 is connected. This valve actuation plate 34
3 is slidably supported on the boss 20b of the clutch casing 20 in the left-right direction in FIG. Return spring 3 for urging operation plate 34
6 is contracted between the clutch casing 20 and the valve operating plate 34.

A pressing ring 38 is mounted on the valve operating plate 34 via a release bearing 37 that concentrically surrounds the boss 20b, and an arm fixed to a transmission clutch operating shaft 39 on the outer end surface of the pressing ring 38. When the transmission clutch operating shaft 39 reciprocates and rotates, the return spring 36
In cooperation with the valve operating plate 34, the inlet valve 26 and the valve rod 31
It can be moved from side to side.

As shown in FIG. 6, an electric or electromagnetic shift clutch actuator 40 for rotating the shift clutch operating shaft 39 is connected to the shift clutch operating shaft 39. An idling sensor 41 for detecting a state, and a transmission M
The output signal of the shift sensor 42 for detecting the shift operation of the valve is input, and in response to any of these signals, the valve actuation plate 34
The shift clutch operating shaft 39 is rotated in a direction to move leftward in FIG.

The operation of the transmission clutch Cc will now be described. When the idling sensor 41 and the transmission sensor 42 do not output any signals during the operation of the engine E, the transmission clutch actuator 40 maintains the non-operating state. Therefore, the valve operating plate 34 is held at the retracted position by the urging force of the return spring 36, that is, at the right-moving position in FIG.
7, the inlet valve 26 is opened and the outlet valve 28 is allowed to close. Therefore,
The oil pumped from the oil pump 44 is supplied from the upstream supply oil passage 27a to the hydraulic chamber 25 in the clutch casing 20 via the first inflow hole 43a and the through hole 30, and the oil is supplied to the chamber 25.
Will be satisfied.

Since the clutch casing 20 rotates together with the crankshaft 2, the oil in the hydraulic chamber 25 of the clutch casing 20 receives a centrifugal force to generate a hydraulic pressure, and the pressurizing plate 21 receives the pressure from the friction clutch plate 23 by the hydraulic pressure. Board 2
2, the pressure plate 21, the pressure receiving plate 2
2 and the friction clutch plate 23 are frictionally engaged. That is, the transmission clutch Cc is turned on, and the output torque of the crankshaft 2 is transmitted from the friction clutch plate 23 to the torque converter T.

On the other hand, at the time of idling of the engine E or at the time of shifting operation of the transmission M, the idling sensor 41 or the shift sensor outputs an output signal.
When the transmission clutch operating shaft 39 is rotated, the valve operating plate 34 is moved to the position shown in FIG.
To move to the left movement position. As a result, as shown in the lower half of FIG. 3, the inlet valve 26 is closed and the outlet valve 28 is opened. As a result, from the upstream supply oil passage 27a to the hydraulic chamber 25
The oil supply to the hydraulic chamber 25 is cut off, and the oil in the hydraulic chamber 25 is discharged to the outside of the clutch casing 20 through the outlet hole 32 and the groove 31a of the valve rod 31 to reduce the oil pressure in the hydraulic chamber 25, and the pressure plate 21 Of the pressure clutch 21, the pressure receiving plate 22, and the friction clutch plate 23 are disengaged from each other. That is, the transmission clutch Cc is in the off state, and interrupts the transmission of torque from the crankshaft 2 to the torque converter T. The oil discharged outside the clutch casing 20 returns to the oil sump 46.

From this state, when the rotation of the engine E is accelerated for starting or when the gear shifting operation is completed,
When both the idling sensor 41 and the speed change sensor 42 stop the output signal, the speed change clutch actuator 40 immediately returns to the non-operating state, and the valve operating plate 34 returns to the return spring 36.
With the urging force of the above, the valve is immediately retracted to the right movement position, and the inlet valve 26 is opened again and the outlet valve 28 is closed.
Will return from the off state to the on state without going through the half-clutch state. That is, the transmission clutch Cc is an on / off type having no half-clutch region, and its torque capacity is set to be larger than that of the torque converter T.

Referring again to FIG. 3, the torque converter T
It comprises a pump impeller 50, a turbine impeller 51 and a stator impeller 52. The pump impeller 50 is arranged adjacent to the pressure receiving plate 22 and has its boss 5
0 a is supported on the crankshaft 2 via the needle bearing 53. A transmission plate 2 which is spline-engaged with the inner periphery of the friction clutch plate 23 is provided on the outer surface of the pump impeller 50.
4 is fixed. Therefore, the friction clutch plate 23
Is transmitted to the pump impeller 50 via the transmission plate 24.

The crankshaft 2 has a pump impeller 50.
The right end of a stator shaft 60 disposed between the boss 50a and the ball bearing 3 'supporting the crankshaft 2 is supported via a needle bearing 54, and the boss of the stator impeller 52 is mounted on the stator shaft 60. 52a are connected by uneven engagement. A stator arm plate 56 is fixed to the left end of the stator shaft 60, and the outer peripheral surface of a cylindrical portion 56 a of the stator arm plate 56 provided at an intermediate portion is supported by the crankcase 1 via a ball bearing 57. The outer peripheral portion of the stator arm plate 56 is supported by the crankcase 1 via a freewheel 58.

The turbine impeller 51 opposed to the pump impeller 50 has a turbine shaft 59 integrally in the center, and the right end thereof has a stator shaft 60 via a needle bearing 61.
The left end is supported on the inner peripheral surface of the cylindrical portion 56a of the stator arm plate 56 via a ball bearing 62. A one-way clutch 64 is provided between the turbine shaft 59 and the crankshaft 2 through a horizontal hole 63 of the stator shaft 60. The one-way clutch 64 is mounted on the turbine shaft 5.
9 is turned on when a reverse load is applied to the turbine shaft 9 so that the turbine shaft 59 and the crankshaft 2 are directly connected.

As shown in FIG. 3, the gap between each of the boss 50a of the pump impeller 50, the turbine shaft 59 and the boss 52a of the stator impeller 52 is used as a fluid inlet 47i of the torque converter T. Turbine impeller 5
1 The fluid outlet 4 of the torque converter T
A fluid inlet 47i communicates with the second inflow hole 43b of the crankshaft 2 and a fluid outlet 47o communicates with the outflow hole 45 of the crankshaft 2 via a lateral hole 63 of the stator shaft 60. . Therefore, when the oil supplied from the oil pump 44 to the upstream supply oil passage 27a of the crankshaft 2 enters the second inflow hole 43b, the oil enters the oil chamber between the pump impeller 50 and the turbine impeller 51 from the fluid inlet 47i. After filling the oil chamber and the hydraulic chamber 77 of the lock-up clutch Lc described later, the fluid outlet 47o
5 to the downstream supply oil passage 27b of the crankshaft 2.

A drive gear 14a of the primary reduction gear 14 is formed integrally with the turbine shaft 59, and a driven gear 14b meshing with the drive gear 14a is spline-coupled to the input shaft 10 of the transmission M. The primary reduction device 14 configured in this manner is disposed between the crankcase 1 and the torque converter T.

The operation of the torque converter T will be described.

When the output torque of the crankshaft 2 is transmitted to the pump impeller 50 via the transmission clutch Cc in the ON state, the torque is transmitted to the turbine impeller 51 by the action of oil filling the torque converter T. Is communicated At this time, if a torque amplifying action occurs between the two impellers 50 and 51, a corresponding reaction force is borne by the stator impeller 52. Fixedly supported. If no torque amplifying action occurs, the stator impeller 52 can idle due to the idling action of the freewheel 58, so that the pump impeller 50,
The three of the turbine impeller 51 and the stator impeller 52 are:
Both rotate in the same direction.

From the pump impeller 50 to the turbine impeller 51
Transmitted to the input shaft 10 of the transmission M via the primary reduction gear 14, and the transmission gear trains G1 to G4, the output shaft 11 and the final reduction gear 19 selected to be established.
Are sequentially transmitted to a rear wheel (not shown) to drive the rear wheel.

During engine braking during running, the one-way clutch 64 is turned on by applying a reverse load torque to the turbine shaft 59, so that the turbine shaft 59 and the crankshaft 2 are directly connected to each other, and the reverse load torque is reduced. Since the power is transmitted to the crankshaft 2 without passing through the converter T, a good engine braking effect can be obtained.

Referring again to FIG. 3, a lock-up clutch Lc is provided between the pump impeller 50 and the turbine impeller 51 so that they can be directly connected. The lock-up clutch Lc is connected to an outer peripheral portion of the pump impeller 50 and surrounds the turbine impeller 51. A cylindrical pump extension 70 and a supporting cylinder rotatably supported on the outer peripheral surface of the turbine shaft 59. A pressure plate 72 slidably fitted to the pressure plate 71 and a pump extension 7 facing the pressure plate 72.
A pressure receiving plate 73 which is oil-tightly fixed to an end of the support cylinder 71 and is spline-fitted to the support cylinder 71;
Annular friction clutch plate 7 interposed between the pressure receiving plate 73
The outer peripheral portion of the friction clutch plate 74 is spline-engaged with a transmission plate 75 fixed to the outer surface of the turbine impeller 51 (see FIG. 9). The pressure plate 72 has its retreating position with respect to the pressure receiving plate 73 defined by a stopper ring 76 locked to the support cylinder 71.

The interior of the pump extension 70 is defined by a pressure receiving plate 73 in a hydraulic chamber 77, which communicates with the inside through a facing gap between the pump impeller 50 and the turbine impeller 51. When the oil is filled and the torque converter T operates, the pressure becomes high similarly to the inside thereof.

As shown in FIGS. 3, 11 and 12, a plurality (three in the example shown) of the pressure plate 72 and the pressure receiving plate 73 are arranged at equal intervals in the circumferential direction on the inner peripheral side of the friction clutch plate 74. One end of a control valve 80 composed of a reed valve, which can open and close the valve hole 78 of the pressure plate 72 on the hydraulic chamber 77 side, is caulked to the pressure plate 72.

The valve holes 78 and 7 of the pressure plate 72 and the pressure receiving plate 73
Reference numerals 9 are arranged coaxially with each other, and a control rod 81 for controlling the opening and closing of the control valve 80 is slidably fitted thereto. The control rod 81 has a communication groove 81a extending in the axial direction on the outer periphery thereof.
3 (see the upper half of FIG. 3 and FIG. 11), the control valve 80 allows the valve hole 78 to be closed by its own elastic force, 81
When the inner peripheral side of the friction clutch plate 74 is opened to the outside of the valve hole 79 of the pressure receiving plate 73 through the communication groove 81a of the pressure receiving plate 73 and occupies the right movement position (see the lower half of FIG. 3 and FIG. 12), the control rod 81
To close the valve hole 79 of the pressure receiving plate 73 and deflect the control valve 80 into the hydraulic chamber 77 so that the friction clutch plate 74
On the inner peripheral side, the both sides of the pressure plate 72 communicate with each other via the communication groove 81a of the control rod 81.

At the outer end of the control rod 81, a valve operating plate 82
Are linked. The valve operating plate 82 is supported on the support cylinder 71 so as to be slidable in the left-right direction in FIG. 3, and a stopper ring 83 for defining its left-moving position is locked to the support cylinder 71. A return spring 84 that urges the valve operating plate 82 toward the valve is contracted between the pressure receiving plate 73 and the valve operating plate 82.

An arm 86a of a lock-up clutch operating shaft 86 (operating means) is engaged with the valve operating plate 82 via a release bearing 85 concentrically arranged with the support cylinder 71, and reciprocates the lock-up clutch operating shaft 86. By rotating, the valve operating plate 82 can be moved right and left together with the control rod 81 in cooperation with the return spring 84.

As shown in FIG. 6, an electric or electromagnetic lock-up clutch actuator 87 for rotating the lock-up clutch operation shaft 86 is connected to the lock-up clutch operation shaft 86.
An output signal of a vehicle speed sensor 88 for detecting a vehicle speed equal to or lower than a predetermined value is input, and in response to the signal, the valve operating plate 82 is moved to the position shown in FIG.
To rotate the lock-up clutch operation shaft 86 in the rightward moving direction.

The operation of the lock-up clutch Lc will be described. When the vehicle speed sensor 88 detects a vehicle speed equal to or lower than a predetermined value and issues an output signal, the lock-up clutch actuator 87 is actuated in response thereto, the lock-up clutch operation shaft 86 is rotated, and the valve operating plate 82 is moved. 3 moves to the right movement position. Accordingly, the lower half of FIG. 3 and FIG.
As shown in FIG. 2, since the control rod 81 opens the control valve 80 and connects both sides of the pressure plate 72 through the communication groove 81a, the oil pressure in the hydraulic chamber 77 acts equally on both sides of the pressure plate 72. The pressing plate 72 is pressed to the retreat position by the pressing force of the control rod 81 against the control valve 80, so that the frictional engagement of the pressing plate 72, the pressure receiving plate 73, and the friction clutch plate 74 does not occur, and the locking is performed. The up clutch Lc exhibits an off state. Therefore, in this state, the relative rotation of the pump impeller 50 and the turbine impeller 51 is possible, and therefore, the torque amplifying operation is possible. Also,
In this case, since the valve hole 79 of the pressure receiving plate 73 is closed by the control rod 81, unnecessary leakage of hydraulic pressure from the hydraulic chamber 77 to the valve hole 79 can be prevented.

When the vehicle speed increases to a predetermined value or more and the vehicle speed sensor 88 stops the output signal, the lock-up clutch actuator 87 returns to the non-operating state, and the valve operating plate 82
11 is retracted to the left position by the biasing force of the return spring 84, as shown in the upper half of FIG. 3 and FIG.
0 is allowed to close the valve hole 78, and the inner peripheral side of the friction clutch plate 74 is opened to the outside of the valve hole 79 through the communication groove 81a of the control rod 81. Only when receiving the hydraulic pressure of the hydraulic chamber 77, the friction clutch plate 7
4 is pressed against the pressure receiving plate 73. As a result, the pressing plate 7
2, the pressure receiving plate 73 and the friction clutch plate 74 are frictionally engaged, and the lock-up clutch Lc is turned on,
Since the pump impeller 50 and the turbine impeller 51 are directly connected to each other, when the motorcycle Vm runs at high speed, slippage between the two impellers 50 and 51 can be eliminated, and transmission efficiency can be increased.

During the operation of the engine E, the oil discharged from the oil pump 44 is first supplied to the upstream supply oil passage 2.
7a, and through the first inflow hole 43a, the transmission clutch Cc.
To the hydraulic chamber 25 of the pump impeller 50 and the turbine impeller 51 and the hydraulic chamber 77 of the lock-up clutch Lc through the second inlet hole 43b. It contributes to the operation and cooling of the torque converter T and the lock-up clutch Lc. The oil flowing from the hydraulic chamber 77 to the downstream supply oil passage 27b from the outflow hole 45 is supplied to the needle bearing 49 on the outer periphery of the crankpin and contributes to the lubrication thereof. It scatters around with rotation and is used for lubrication of the piston 7 and the like. Although the oil pump 44 originally supplies lubricating oil to the engine E, the oil is used as working oil for the transmission clutch Cc, the torque converter T, and the lock-up clutch Lc. Therefore, there is no need to provide a dedicated oil pump for supplying the working oil, and the configuration can be simplified.

The upstream supply oil passage 27a and the downstream supply oil passage 27b provided on the crankshaft 2 are also directly communicated via the orifice 48.
A part of the oil sent to the upstream supply oil passage 27a from the oil supply passage 27a moves directly to the downstream supply oil passage 27b through the orifice 48 without passing through the torque converter T or the like.
, The distribution ratio of oil to the torque converter T and the engine E can be set freely.

On the other hand, in the torque converter T, even when the engine E is idling, some torque transmission occurs between the pump impeller 50 and the turbine impeller 51. During idling, the transmission clutch Cc is turned off as described above. , The first of the multi-stage transmission M
Even if the speed gear train G1 is established, power transmission to the transmission clutch Cc and thereafter can be cut off regardless of the presence of the torque converter T, thereby preventing the creep phenomenon. This means that each transmission member of the multi-stage transmission M is placed in a no-load state, and therefore, for starting the motorcycle Vm,
Even in the case where the shift gear G2b is shifted to the left in FIG. 2 to establish the first speed gear train G1, a smooth shift can be performed without a torque shock. Then, when the rotation of the engine E is accelerated to start, the transmission clutch C
Although c jumps over the half-clutch region and shifts to the ON state at once, the torque shock accompanying it is absorbed by the sliding action between the pump impeller 50 and the turbine impeller 51 of the torque converter T, and their amplifying action is also helped. As a result, a smooth start can be performed, which can contribute to an improvement in riding comfort.

When the shift gears G2b and G3a are shifted in a desired direction during traveling and a desired shift is performed, the transmission clutch Cc is controlled to the off state each time as described above, and the multi-stage transmission M Since each of the transmission members is in a no-load state, a smooth gear shift can be performed without a torque shock. Even after shifting, the shift clutch Cc jumps over the half-clutch region and shifts to the ON state at a stretch, but the accompanying torque shock is also absorbed by the sliding action between the pump impeller 50 and the turbine impeller 51 of the torque converter T. You. Therefore, the ride comfort is improved without giving the occupant a sense of discomfort.

As described above, since the torque converter T absorbs the torque shock caused by the on / off operation of the transmission clutch Cc, the transmission clutch Cc is constituted as an on / off type having no half-clutch region. Therefore, heat generation and wear of the friction portion due to the half clutch can be avoided, and the durability of the transmission clutch Cc can be improved.

Further, since the torque capacity of the transmission clutch Cc is set to be greater than that of the torque converter T, slippage of the transmission clutch Cc can be prevented even under full load, and its durability can be ensured.

The crankshaft 2 is provided with a
The transmission rotates at a higher speed than the input shaft 10 of the multi-stage transmission M driven by the torque converter T, the transmission torque borne by the torque converter T mounted on the crankshaft 2 and the transmission clutch Cc is relatively small. The capacity of each of the T and the transmission clutch Cc can be reduced to make them compact, and even if the torque converter T and the transmission clutch Cc are provided together, the power unit P
Can be made more compact.

Further, of the primary reduction gear 14, the torque converter T and the transmission clutch Cc, the primary reduction gear 14 is arranged closest to the right side wall of the crankcase 1, and the torque converter T is arranged next to the next. Therefore, the bending moment applied to the crankshaft 2 and the input shaft 10 with the operation of the primary reduction gear 14 can be minimized, and the torque converter T is heavier than the transmission clutch Cc.
Due to their weight, the bending moment applied to the crankshaft 2 can also be minimized, and together with the compactness of the torque converter T and the speed change clutch Cc, the crankshaft 2, the input shaft 10 and the bearing 3 'for supporting them. ,
12 ′ can be improved in durability.

A primary reduction gear 1 is provided on the crankshaft 2.
4. Since the torque converter T, the speed change clutch Cc, the timing transmission 91, and the generator 16 are arranged on opposite sides of the crank chamber, the weight distribution of the power unit P to the left and right can be equalized. In addition, in the four-stroke engine E, the primary reduction gear 14 can be arranged close to the right side wall of the crankcase 1 without any interference from the timing transmission 91, and the crankshaft 2, the input shaft 10 and bearings 3 ', 12' for supporting them
Durability can be ensured.

Further, the generator 16 and the torque converter T
The rotational vibration generated in the generator 16 can be absorbed by the torque converter T, thereby contributing to the quietness of the power unit P.

Next, a second embodiment of the present invention shown in FIG. 13 will be described.

The second embodiment differs from the previous two embodiments in that the lock-up clutch Lc 'is of an automatic control type dependent on the rotation speed of the pump impeller 50. That is, the lock-up clutch Lc ′ is rotatably supported by a cylindrical pump extension 70, which is connected to the outer periphery of the pump impeller 50 and surrounds the turbine impeller 51, and the turbine shaft 59. A pressure receiving plate 93, which is oil-tightly connected to the open end of the pump extension 70, and a pressure plate 94 slidably supported by the turbine shaft 59 and arranged to face the inner surface of the pressure receiving plate 93.
And an annular friction clutch plate 95 interposed between the pressure plate 94 and the pressure receiving plate 93 and a pressure plate 94 interposed between the pump extension 70 and the pressure plate 94 to attach the pressure plate 94 in a direction opposite to the pressure receiving plate 93. A biasing disc-shaped return spring 96 is provided, and its friction clutch plate 95 is spline-engaged at its outer peripheral portion with a transmission plate 75 fixed to the outer surface of the turbine impeller 51. The pressure receiving plate 93 and the pressure plate 94 are formed with dogs 97 and recesses 98 that engage with each other on opposite surfaces so that they can rotate relative to each other in the axial direction while rotating together.

The interior of the pump extension 70 is defined by a pressure receiving plate 93 in a hydraulic chamber 99 which communicates with the interior of the pump impeller 50 and the turbine impeller 51 through opposing gaps. Oil is filled.

The pressure receiving plate 93 is provided with a relief hole 100 for opening the inner peripheral side of the friction clutch plate 95 to the outside of the pressure receiving plate 93, and an air vent groove 101 extending in the axial direction on the inner peripheral surface of the pressure receiving plate 93.

Since the other structure is the same as that of the first embodiment, the same reference numerals in the drawing denote the same parts as in the first embodiment, and a description thereof will be omitted.

When the rotation speed of the pump impeller 50 is lower than the predetermined rotation speed, the centrifugal force of the oil filling the hydraulic chamber 99 in the pump extension 70 has a small centrifugal force. Is returned to the retracted position by the urging force of the return spring 96 and the friction clutch plate 95 is released, so that the lock-up clutch Lc 'is in the off state.

During this time, the oil in the hydraulic chamber 99 is
3 flows out to the outside through the escape hole 100, but the amount is extremely small, so that it does not hinder the subsequent pressurization of the hydraulic chamber 99.

When the rotation speed of the pump impeller 50 exceeds a predetermined value, the centrifugal force of the oil in the hydraulic chamber 99 increases correspondingly and the hydraulic chamber 99 is pressurized. Advancing toward 93, the pressure receiving plate 9
3, the friction clutch plate 95 is pinched, and the lock-up clutch Lc 'is turned on. The lock-up clutch Lc ′ in the ON state brings the pump impeller 50 and the turbine impeller 51 into a directly connected state, so that the two impellers 5
The transmission efficiency can be increased by eliminating mutual slippage between 0 and 51.

At this time, on the inner peripheral side of the friction clutch plate 95, no pressure rise occurs due to the oil flowing out from the escape hole 100, so that a large pressure difference is generated between both surfaces of the pressure plate 94, and the friction clutch plate 95 Is effectively performed.

Thus, by utilizing the centrifugal hydraulic pressure in the hydraulic chamber 99 in the pump extension 70 connected to the pump impeller 50,
The automatic control of the lock-up clutch Lc 'can be easily made dependent on the rotation speed of the pump impeller.

Next, a third embodiment of the present invention shown in FIG. 14 will be described.

The third embodiment differs from the second embodiment in that the lock-up clutch Lc "is of an automatic control type dependent on the rotation speed of the turbine impeller 52. The lock-up clutch Lc" The pump impeller 50 is oil-tightly coupled to the pump extension 70 and is disposed outside the torque converter side cover 105 that covers the turbine impeller 51. The torque converter side cover 105 is rotatably supported on the outer periphery of the turbine shaft 59, and the inside thereof communicates with an oil chamber between the pump impeller 50 and the turbine impeller 51, and the hydraulic oil similarly to the oil chamber. Is to be filled with.

The lock-up clutch Lc ″ is spline-coupled to the left end of the turbine shaft 59, and has a flat clutch cylinder 106 having an open end facing the torque converter side cover 105 and a cylinder hole 106 a of the clutch cylinder 106. A pressurizing piston 107 which is slidably fitted via a seal member 113 and defines a hydraulic chamber 108 with an end wall of the clutch cylinder 106, and near an open end of the inner peripheral surface of the clutch cylinder 106. Pressure receiving ring 109 to be locked, pressure receiving ring 109 and pressurizing piston 1
07, a plurality of (two in the illustrated example) annular driven friction clutch plates 111, 111 slidably engaged with the inner peripheral surface of the clutch cylinder 106, and between the driven friction clutch plates 111, 111. An annular driving friction clutch plate 110 which is interposed and engages a plurality of transmission claws 112 projecting outside the torque converter side cover 105 so that the inner peripheral surface thereof can slide in the axial direction; On the inner peripheral side of the dynamic friction clutch plates 110 and 111, the pressurizing piston 107 and the torque converter side cover 1
The pressurizing piston 107 is disposed between the hydraulic chamber 10 and the hydraulic chamber 10.
And a piston return spring 114 that urges the clutch cylinder 106 and the pressurizing piston 10
7 has dogs 115 and recesses 116 which are engaged with each other on opposite surfaces so that they can rotate relative to each other in the axial direction while rotating together.

The turbine shaft 59 is provided with a fluid outlet 47o and an inlet hole 117 for communicating the inside of the torque converter side cover 105 and the hydraulic chamber 108 of the clutch cylinder 106 with the inner peripheral side of the turbine shaft 59, respectively. The interior of the torque converter side cover 105 and the hydraulic chamber 108 of the clutch cylinder 106 communicate with each other through the outlet 47o and the inlet hole 117 and the inside of the turbine shaft 59.

A plurality of relief holes 118 are formed in the peripheral wall of the clutch cylinder 106 at equal intervals in the circumferential direction to open the hydraulic chamber 108 to the outside of the clutch cylinder 106. Is provided with an annular groove 119 communicating between the escape holes 118, and a centrifugal valve 120 for closing the escape hole 118 with a centrifugal force at a predetermined rotational speed or more of the clutch cylinder 106 is provided in the annular groove 119. . The centrifugal valve 120 is composed of a free end ring made of a single elastic wire, and at least one end 120 a of the centrifugal valve 120
16 and rotate with the pressurizing piston 107 and thus the clutch cylinder 106. In the free state, the centrifugal valve 120 contracts in the radial direction so as to open the escape hole 118. However, when the rotational speed of the clutch cylinder 106 exceeds a predetermined value, the centrifugal valve 120 expands in the radial direction by centrifugal force to expand the annular groove. It is in close contact with the bottom surface of 119, so that all escape holes 118 are closed.

Since the other structure is the same as that of the first embodiment, the same reference numerals in the drawing denote the same parts as in the first embodiment, and a description thereof will be omitted.

When the oil supplied from the oil pump 44 to the upstream supply oil passage 27a of the crankshaft 2 enters the second inflow hole 43b, the pump impeller 5
After entering the oil chamber between the oil turbine and the turbine impeller 51 and filling the oil chamber and the inside of the torque converter side cover 105, the oil flows out of the fluid outlet 47 o into the turbine shaft 59.
The oil that has flowed into the turbine shaft 59 is diverted to the inlet hole 117 and the outlet hole 45, and the oil that has moved to the inlet hole 117 flows into the hydraulic chamber 108 of the lock-up clutch Lc ″, and has moved to the outlet hole 45. Flows to the downstream supply oil passage 27b of the crankshaft 2 as in the case of the previous embodiment.

By the way, the clutch cylinder 106 of the lock-up clutch Lc ″ is spline-coupled to the turbine shaft 59 and rotates together with the turbine shaft 59. In contrast, the contraction state is maintained, and the escape hole 118 is opened.
The oil that has flowed into the hydraulic cylinder 108 flows out of the clutch cylinder 106 through the escape hole 118, so that the oil pressure in the hydraulic chamber 108 does not rise, and the pressurizing piston 107
And the driven and driven friction clutch plates 110 and 111 are disengaged. That is, the lock-up clutch Lc ″ is in the off state.

At this time, if foreign matter such as chips or abrasion powder is present in the hydraulic chamber 108, the foreign matter can be discharged out of the clutch cylinder 106 through the escape hole 118 together with the oil.

When the number of revolutions of the turbine shaft 59 exceeds a predetermined value, the centrifugal valve 120 rotating therewith expands due to the increased own centrifugal force and closes all the relief holes 118. As a result, the hydraulic chamber 108 is filled with oil supplied from the inlet hole 117, and a hydraulic pressure is generated in the hydraulic chamber 108 due to the centrifugal force of the oil. The lock-up clutch Lc ″ is turned on by moving forward and bringing the driven and driven friction clutch plates 110 and 111 into a frictionally engaged state.
In the case of c ″, the pump impeller 50 and the turbine shaft 59 are directly connected to each other, so that slippage between the pump impeller 50 and the turbine impeller 51 can be eliminated, and the transmission efficiency can be increased.

When the number of revolutions of the turbine shaft 59 drops below a predetermined value, the centrifugal valve 120 opens again.
08 can be quickly released from the relief hole 118, and the off performance of the lock-up clutch Lc "can be improved.

Thus, by utilizing the centrifugal oil pressure of the hydraulic chamber 108 in the clutch cylinder 106 connected to the turbine shaft 59, the automatic control of the lock-up clutch Lc "can easily be made independent of the turbine impeller speed. be able to.

Finally, a fourth embodiment of the present invention shown in FIGS. 15 to 17 will be described.

First, in FIGS. 15 and 16, the four-wheel buggy Vb includes a pair of front wheels Wfa, Wfb and a rear wheel Wf.
A fuel tank Tfb is mounted on a front part and a saddle Sb is mounted on a rear part, and a power unit P is mounted on a lower part of the body frame Fb supporting the ra and Wrb. The left and right front wheel drive shafts 121a and 121b connected to the left and right front wheels Wfa and Wfb are connected to each other via a differential device 122, and the left and right rear wheels Wra and Wrb are directly connected by one rear wheel drive shaft 123. Is done.

The power unit P is arranged such that the crankshaft 2 of the engine E is directed in the left-right direction of the four-wheel buggy Vb. A bevel gear transmission 125 is connected to the output shaft 11 of the transmission M.
The drive shaft 126 is connected to the power unit P on the generator 16 side and is disposed in the front-rear direction. The front end of the drive shaft 126 is connected to the intermediate gear transmission 12.
7. Front propeller shaft 128 and bevel gear reducer 12
9 and the rear end of the drive shaft 126 is connected to the universal joint 130 and the rear propeller shaft 13.
1 and a bevel gear reduction device 132 connected to the rear wheel drive shaft 123. Therefore, the power unit P
Of the front wheels Wfa,
Wfb and the rear wheels Wra, Wrb can be driven.

As shown in FIG. 17, the power unit P of the fourth embodiment differs from the first embodiment in the structure of the transmission clutch Cc 'and the torque converter T'.

The transmission clutch Cc 'is slidable on a drive plate 135 which is spline-fitted to the crankshaft 2 and fixed by a nut 134, and a support cylinder 136 which is integrally provided on the outer surface of the drive plate 135. And a clutch outer 137 having a bottomed cylindrical shape and supported by the clutch outer 137. The drive plate 135 is disposed adjacent to the end wall of the clutch outer 137,
The outer periphery is spline-coupled to the inner periphery of the clutch outer 137. A clutch inner 138 is coaxially arranged in the clutch outer 137, and a plurality of annular drive friction plates 139 slidably engaged with the inner periphery of the cylindrical portion of the clutch outer 137, and the outer periphery of the clutch inner 138 slides. A plurality of movably engaged annular driven friction plates 140 are alternately stacked. At this time, these friction plates 13
Out of the 9,140 groups, two driving friction plates 139,1
The pressure receiving ring 141 facing the outer surface of the outer driving friction plate 139 is engaged with the inner periphery of the cylindrical portion of the clutch outer 137.

Between the driving friction plates 139, 139 on both sides, a separation spring 142 for urging them in the separation direction is contracted. A flange 138a protruding from the outer periphery of the clutch inner 138 is opposed to the inner driven friction plate 140.

The driving plate 135 includes a plurality of centrifugal weights 14.
3 is pivotally mounted by a pivot 144, and the pressing arm 143a of each centrifugal weight 143 is
39 is arranged so as to be able to be pressed. The drive plate 135
Is provided with a stopper 145 that defines a sliding limit of the clutch outer 137 outward (to the right in FIG. 17). The clutch spring 146 biases the clutch outer 137 toward the stopper 145. Is mounted between the drive plate 135 and the clutch outer 137.

An annular transmission member 148 is connected to the clutch inner 138 via a well-known reverse load transmission screw mechanism 147, and this transmission member 148 is connected to the torque converter T '.
Is spline-coupled to the outer periphery of the boss 50a of the pump impeller 50.

When the engine E is idling, the driving plate 135 that rotates together with the crankshaft 2 has a low rotation speed and the centrifugal force of the weight of the centrifugal weight 143 is small, so that the driving friction of the pressing arm 143a is small. The pressing force against the plate 139 is also small. Therefore, the driving friction plates 139, 13 on both sides
9 is separated by the urging force of the separation spring 142 to release the driven friction plate 140, and the transmission clutch Cc 'is in the off state. Therefore, the transmission clutch Cc 'in the off state cuts off the transmission of power from the crankshaft 2 to the pump impeller 50 of the torque converter T'. Slow advance of the buggy Vb can be prevented.

When the number of revolutions of the engine E rises above a predetermined value, the centrifugal force of the weight of the centrifugal weight 143 increases, and the pressing arm 143a drives the driven and driven friction plates 1.
Press the 39 and 140 groups strongly against the pressure receiving ring 141,
Since the driving and driven friction plates 139 and 140 are frictionally engaged, the transmission clutch Cc 'is automatically turned on,
The power of the crankshaft 2 is transmitted from the clutch inner 138 via the transmission member 148 to the pump impeller 50 of the torque converter T '.

Driving of the centrifugal weight 143 and the driven friction plate 13
If the pressing force on the groups 9 and 140 exceeds the set load of the clutch spring 146, the clutch outer 137 is displaced leftward in FIG. 17 while bending the clutch spring 146. After that, the centrifugal weight 143 is moved to the clutch outer 137.
Is stopped by a stopper ring 157 provided in the clutch spring 146, so that the pressing force between the driving and driven friction plates 139 and 140 is larger than the load of the clutch spring 146. Does not increase.

The clutch outer 137 has a boss 137a protruding from the outer surface thereof.
And the release cam 1 via the release bearing 149
50 is attached. A fixed cam 152 attached to the right side cover 15a via an adjustment bolt 151 is opposed to the release cam 150, and the fixed cam 152
Is engaged with the concave portion 150a of the release cam 150.

In the release cam 150, an arm 154 having a notch 154a at the tip is projected in the radial direction. The notch 154a has a clutch arm 156 fixed to a change spindle 155 used for switching operation of the transmission M. Are engaged.

When the change spindle 155 is rotated to switch the transmission M during traveling of the four-wheel buggy Vb, the clutch arm 156 rotates the release cam 150 in the first half of the rotation. , With release cam 15
0 is the ball 1 of the fixed cam 152 from the recess 150a.
The clutch outer 137 is pushed to the left in the figure against the load of the clutch spring 146 via the release bearing 149 by the reaction force at that time, and the pressure receiving ring 14 is pushed.
1 is separated from the driving and driven friction plates 139 and 140 group. On the other hand, the centrifugal weight 143 is prevented from swinging outward by the stopper ring 157 as described above, and
Since a stops at the previously pressed position of the drive and driven friction plates 139 and 140, the drive and driven friction plates 139 and 140 are surely separated from each other, and the transmission clutch Cc 'is turned off.

The rotation of the change spindle 155 in the latter half is used for switching the transmission M. After the change, the release cam 150 is returned to the initial position with the return rotation of the change spindle 155, and the transmission clutch Cc 'is turned on. The clutch spring 146 is returned to the ON state by the cooperation of the urging force of the clutch spring 146 and the continued centrifugal force of the centrifugal weight 143.

In the torque converter T ', the pump impeller 50 spline-coupled to the transmission member 148 is used.
Boss 50a is provided with a ball bearing 159 on the crankshaft 2.
, And the turbine shaft 59 connected to the turbine impeller 51 is supported on the stator shaft 60 via left and right needle bearings 160 and ball bearings 161. The boss 52 a of the stator impeller 52 is supported on the crankshaft 2 via a ball bearing 162 or a needle bearing, and is spline-coupled to the stator shaft 60.

The pump extension 7 connected to the pump impeller 50
In FIG. 2, a torque converter side cover 163 that covers the outside of the turbine impeller 51 is oil-tightly coupled. Between the torque converter side cover 163 and the turbine shaft 59, the torque converter side cover 163 is connected to the torque converter side cover 163. A one-way clutch 64 that transmits only reverse load torque is provided. Therefore, during engine braking,
When the reverse load torque applied to the drive shaft 126 is transmitted to the turbine shaft 59 via the transmission M and the primary reduction gear 14, the one-way clutch 64 is engaged, and the reverse load torque is transmitted to the pump extension 70. From the pump impeller 50 and the transmission member 148.

When the reverse load torque is transmitted to the transmission member 148, in the transmission clutch Cc ', the operation of the screw mechanism 147 causes the clutch inner 138 to be pushed leftward in FIG. Friction plate 139
, The drive and driven friction plates 139 and 140 are pressed against the pressure receiving ring 141, so that the transmission clutch Cc 'is turned on. Therefore, the reverse load torque is transmitted to the crankshaft 2, and a good engine braking effect is obtained.

The crankshaft 2 is provided with a partition 165 for partitioning between the upstream supply oil passage 27a and the downstream supply oil passage 27b, and the upstream supply oil passage 27a is further divided into an upstream side and a downstream side. The partition plug 166 is press-fitted.

In the transmission clutch Cc ', an oil chamber 168 is defined in the support cylinder 136 with its open surface closed by a lid 167, and the oil chamber 168 is connected to the clutch inner 138 through a through hole 169. Is communicated to the inner peripheral side of the. The oil chamber 169 communicates with the upstream and downstream sides of the upstream supply oil passage 27a via an inflow hole 170 and an outflow hole 171 formed in the crankshaft 2.

In the torque converter T ',
The first small oil chamber 1 is located on the right side of the boss 52a of the stator impeller 52.
72, a second small oil chamber 173 is provided on the left side, and the first small oil chamber 172 communicates with an oil chamber between the pump impeller 50 and the turbine impeller 51 and an inflow hole formed in the crankshaft 2. The second small oil chamber 173 communicates with the oil chamber between the turbine wheel 51 and the stator impeller 52 through the hole 175 to the downstream side of the upstream oil supply passage 27a. The downstream oil supply passage 27b communicates with the downstream supply oil passage 27b through the outlet hole 176.

Furthermore, the first and second small oil chambers 172, 173
Communicate with each other through the gaps of the bearings 162 that support the boss 52a and through holes 174 provided in the boss 52a.

When oil is supplied from the oil pump 44 driven by the engine E to the upstream supply oil passage 27a through the oil passage 27, the oil enters the oil chamber 168 through the inflow hole 170 and passes therethrough. Hole 169 and outflow hole 17
The oil that has diverted to 1 and passed through the through hole 169 is supplied to the friction portion and the sliding portion of the transmission clutch Cc ′, and contributes to cooling and lubrication thereof.

On the other hand, the oil passing through the outflow hole 171
The oil chamber between the pump impeller 50 and the turbine impeller 51 passes from the inflow hole 175 through the first small oil chamber 172 through the downstream side of the upstream supply oil passage 27a, and then the second small oil chamber 17
3 and flows out to the downstream supply oil passage 27b through the outflow hole 176, and is used for lubrication of various parts of the engine E.

The boss 52 of the stator impeller 52
Since a is supported on the crankshaft 2 via the bearing 162, stable rotation is ensured. In addition, since the bearing 162 has both end faces facing the first and second small oil chambers 172 and 173 on both sides of the boss 52a, the bearing 162 can be always kept in a good lubrication state. Further, since the first and second small oil chambers 172 and 173 communicate with each other via the bearing 162 and the through hole 174, if the amount of oil supplied from the oil pump 44 is small, the pump impeller 50 will When a large amount of oil is to be sucked inside by the rotation, the first small oil chamber 1
Insufficient oil supply to 72, but the second
Since oil flows from the small oil chamber 173 to the first small oil chamber 172 through the through hole 174 and the bearing 162, the generation of bubbles in the oil in the torque converter T 'is suppressed, and the transmission efficiency is prevented from lowering. Can be effectively lubricated.

Incidentally, between the first and second oil chambers 172 and 173, a through hole 17 provided around the bearing 162 is provided.
Communication can be through 4 ', or through both.

The upstream supply oil passage 27a in the crankshaft 2
And the downstream supply oil passage 27b is provided with the inflow hole 175 and the outflow hole 1
Since the direct communication is interrupted by the partition 165 between the oil pumps 76, the oil supplied from the oil pump 44 to the upstream supply oil passage 27a passes through the inflow hole 175 and the outflow hole 176 to pass through the inside of the torque converter T '. As a result, even if the oil pump 44 has a relatively small capacity, shortage of working oil of the torque converter T 'can be prevented as much as possible, which is effective for small vehicles.

The other structure is substantially the same as that of the first embodiment. In FIGS. 15 to 17, parts corresponding to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. .

The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist of the present invention. For example, the transmission clutches Cc and Cc 'are arranged on the transmission path between the engine E and the primary reduction gear 14 between the engine E and the torque converters T and T' in the above embodiment. ′ And the primary speed reducer 14. Further, the torque converters T and T 'can be replaced with fluid couplings having no torque amplification function.

[0126]

As described above, according to the first aspect of the present invention, the crankshaft of the engine and the input shaft of the multi-stage transmission are connected to the pump impeller connected to the engine and the turbine connected to the multi-stage transmission. In a transmission for a small vehicle, which is connected through a fluid transmission means having an impeller, a transmission clutch in series with the fluid transmission means is interposed between an engine crankshaft and an input shaft of a multi-stage transmission; A lock-up clutch is provided between the pump impeller and the turbine impeller of the fluid transmission means so that the two impellers can be directly connected to each other. Elimination of the phenomenon and light shifting without torque shock can be achieved. During cruising, the lock-up clutch is switched on. Ri, eliminating the slippage between the pump impeller and the turbine impeller, thereby improving the transmission efficiency.

According to the second feature of the present invention, the lock-up clutch is connected to the pump impeller and surrounds the turbine impeller, and the pump extension is connected to the tip of the pump extension to extend the pump extension. A pressure receiving plate defining a hydraulic chamber communicating with an oil chamber between the pump impeller and the turbine impeller, a pressure plate opposed to the pressure receiving plate and biased toward the pressure receiving plate by the hydraulic pressure of the hydraulic chamber; An annular friction clutch plate interposed between the pressure receiving plate and the pressure plate and connected to the turbine impeller; and first and second friction clutch plates provided on the pressure plate and the pressure receiving plate on the inner peripheral side of the friction clutch plate, respectively. A valve hole, a control valve provided on the pressurizing plate to close the first valve hole, and fitted in the first and second valve holes to allow the control valve to be closed. A retracted position to open the peripheral side out of the second valve hole; A control rod which can move between forward positions where the valve hole is closed and the control valve is opened to open the inner peripheral side of the friction clutch plate to the hydraulic chamber, and operating means for operating the control rod are provided. The lock-up clutch is turned on using the hydraulic pressure of the fluid transmission
Off control can be performed, and unnecessary leakage of hydraulic pressure from the hydraulic chamber can be prevented even during off control in which the control rod is advanced.

According to the third feature of the present invention, a one-way clutch which is turned on when the turbine impeller receives a reverse load torque is interposed between the crankshaft and the turbine impeller. When the one-way clutch is turned on, the turbine impeller and the crankshaft are directly connected to each other, and the reverse load torque is transmitted to the crankshaft without passing through the fluid transmission means. The effect can be obtained.

Further, according to a fourth feature of the present invention,
The lock-up clutch is configured to operate automatically when the rotation speed of the pump impeller exceeds a predetermined value. When the rotation speed of the pump impeller exceeds the predetermined value, fluid transmission is performed. The pump impeller and the turbine impeller of the means can be directly connected automatically.

Still further, according to a fifth aspect of the present invention, a lock-up clutch is connected to a pump impeller, which is connected to the pump impeller, and surrounds the turbine impeller. A pressure plate defining an oil pressure chamber communicating with an oil chamber between the pump impeller and the turbine impeller in the extension portion, a pressure plate opposed to the pressure plate so as to be able to advance and retreat, and an interposition between the pressure plate and the pressure plate. An annular friction clutch plate connected to the turbine impeller and a return spring biasing the pressure plate in a direction to retract the pressure plate with respect to the pressure receiving plate, and communicating between the inside and outside of the pressure receiving plate on the inner peripheral side of the friction clutch plate. The pressure plate cooperates with the pressure receiving plate to pinch the friction clutch plate by the centrifugal oil pressure in the hydraulic chamber that rises accordingly when the rotation speed of the pump impeller exceeds a predetermined value. Because It can be easily performed automatic control of the pump impeller rotation speed dependent for click-up clutch.

Further, according to a sixth aspect of the present invention,
The lock-up clutch is configured to operate automatically when the rotation speed of the turbine impeller exceeds a predetermined value. When the rotation speed of the turbine impeller exceeds the predetermined value, the fluid transmission is performed. The pump impeller and the turbine impeller of the means can be directly connected automatically.

Further, according to a seventh aspect of the present invention,
A clutch cylinder in which a lock-up clutch is connected to a turbine impeller; a pressurizing piston slidably fitted in a cylinder hole of the clutch cylinder to define a hydraulic chamber; It consists of a biasing piston return spring, a means for introducing oil into the hydraulic chamber, and a frictional engagement means provided between the clutch cylinder and the pump impeller. When the rotation speed of the turbine impeller exceeds a predetermined value, the The pressurizing piston operates the friction engagement means by the centrifugal oil pressure in the hydraulic chamber which rises accordingly to connect the clutch cylinder and the pump impeller, so that the turbine impeller rotation speed-dependent automatic control for the lock-up clutch is performed. Can be done easily.

Further, according to an eighth aspect of the present invention,
The clutch cylinder is provided with a relief hole for opening the outer peripheral side of the hydraulic chamber to the outside, and a centrifugal valve for opening the relief hole when the rotational speed of the clutch cylinder is less than a predetermined value and closing the relief hole when the rotation speed of the clutch cylinder is higher than a predetermined value. Therefore, when the rotation speed of the clutch cylinder is lower than the predetermined rotation speed, the residual pressure of the hydraulic chamber is released from the release hole by opening the centrifugal valve to quickly release the lock-up clutch and improve the performance of the lock-up clutch. Can be discharged from the escape hole together with the oil, and at a predetermined rotational speed or more, the centrifugal valve is closed so that the pressure in the hydraulic chamber can be increased, and the operation of the lock-up clutch is not hindered.

[Brief description of the drawings]

FIG. 1 is a side view of a motorcycle according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a power unit mounted on the motorcycle.

FIG. 3 is an enlarged vertical cross-sectional view of a transmission of the power unit.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a view taken in the direction of arrows 5-5 in FIG. 3;

FIG. 6 is a side view of the transmission.

FIG. 7 is an enlarged view showing an outlet valve of the transmission clutch in FIG. 3 in a closed state.

FIG. 8 is an enlarged view showing the outlet valve in an open state.

FIG. 9 is a sectional view taken along line 9-9 of FIG. 3;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 3;

FIG. 11 is an enlarged view showing a control valve of the lock-up clutch of FIG. 3 in a closed state.

FIG. 12 is an enlarged view showing the control valve in an open state.

FIG. 13 is a sectional view corresponding to FIG. 3, showing a second embodiment of the present invention;

FIG. 14 is a sectional view showing a third embodiment of the present invention and corresponding to FIG. 3;

FIG. 15 is a side view of a four-wheeled buggy according to a fourth embodiment of the present invention.

FIG. 16 is a plan view showing the power unit of the four-wheeled buggy in a longitudinal section.

FIG. 17 is an enlarged vertical sectional view of a transmission of the power unit.

[Explanation of symbols]

Cc, Cc ', Cc "... Shift clutch E ... Engine Lc, Lc', Lc" ... Lock-up clutch M ... Multi-stage transmission T, T '... Fluid transmission means (torque converter) 2 ... Crankshaft 10 ... Input shaft of transmission 50 ... Pump impeller 51 ... Turbine impeller 70 ... · Pump extension 72 ···· Pressure plate 73 ···· Pressure receiving plate 74 ··· Friction clutch plate 77 ···· Hydraulic chamber 78 ··· First valve hole 79 ··· Control valve 81 Control rod 86 Operating means (lock-up clutch operating shaft) 93 Pressure receiving plate 94 ··· Pressing plate 95 ···· Friction clutch plate 96 ··· Return spring 99 ··· Hydraulic chamber 100 ··· Release hole 106 ··· Clutch cylinder 106a ··· Cylinder hole 107 ··· Pressurizing piston 108 ··· Hydraulic chamber 110-112 ··· Friction engagement means 114 ··· Piston return spring 117 ··· Oil introduction means (inlet hole) 118 ··· Escape hole 120 ··· Centrifugal valve

Claims (8)

[Claims] 1. A crankshaft (2) of an engine (E),
A fluid transmission means having an input shaft (10) of the multi-stage transmission (M) and a pump impeller (50) connected to the engine (E) side and a turbine impeller (51) connected to the multi-stage transmission (M) side. T), a transmission system for a small vehicle, which is connected in series with the fluid transmission means (T) between the crankshaft (2) of the engine (E) and the input shaft (10) of the multi-stage transmission (M). The transmission clutch (Cc) is interposed between the pump impeller (50) and the turbine impeller (51) of the fluid transmission means (T).
51) can be directly connected to each other.
c, Lc ′, Lc ″). 2. The transmission for a small vehicle according to claim 1, wherein the lock-up clutch (Lc) is connected to the pump impeller (50) and surrounds the turbine impeller (51). ) And this pump extension (70)
A pressure receiving plate (73) coupled to the tip of the pump and defining a hydraulic chamber (77) in the pump extension (70) communicating with the oil chamber between the pump impeller (50) and the turbine impeller (51). ,
A pressure plate (72) opposed to the pressure receiving plate (73) and urged toward the pressure receiving plate (73) by the hydraulic pressure of the hydraulic chamber (77).
An annular friction clutch plate (74) interposed between the pressure receiving plate (73) and the pressure plate (72) and connected to the turbine impeller (51); and an inner periphery of the friction clutch plate (74). First and second valve holes (78, 79) provided on the pressure plate (72) and the pressure receiving plate (73), respectively, and the pressure plate (72) provided to close the first valve holes (78). Control valve (80) and first and second valve holes (78, 79)
To allow the control valve (80) to close, a retracted position to open the inner peripheral side of the friction clutch plate (74) out of the second valve hole (79), and a second valve hole. (79) a control rod (81) movable between forward positions for opening the control valve (80) and opening the inner peripheral side of the friction clutch plate (74) to the hydraulic chamber (77); A transmission for a small vehicle, comprising an operating means (86) for operating the control rod (81). 3. The transmission for a small vehicle according to claim 1, wherein the crankshaft (2) and the turbine impeller (5) are provided.
1) A transmission for a small vehicle, wherein a one-way clutch (64) that is turned on when the turbine impeller (51) receives a reverse load torque is interposed therebetween. 4. The transmission for a small vehicle according to claim 1, wherein the lock-up clutch (Lc ′) is automatically activated when the rotation speed of the pump impeller becomes equal to or higher than a predetermined value. Characterized in that it is formed into a mold,
Transmission for small vehicles. 5. The transmission for a small vehicle according to claim 4, wherein the lock-up clutch (Lc ′) is connected to the pump impeller (50) and surrounds the turbine impeller (51). 70) and this pump extension (7
The pressure receiving plate (93) coupled to the tip of the pump impeller (70) and defining a hydraulic chamber (99) in the pump extension (70) and communicating with the oil chamber between the pump impeller (50) and the turbine impeller (51). )
And a pressure plate (94), which is provided to be able to advance and retreat to the pressure receiving plate (93), and is interposed between the pressure receiving plate (93) and the pressure plate (94) and is connected to the turbine impeller (51). An annular friction clutch plate (95), a return spring (96) for urging the pressure plate (94) in a direction to retract the pressure plate (93) with respect to the pressure receiving plate (93); A relief hole (100) communicating the inside and outside of the plate (93) with the centrifugal oil pressure in the hydraulic chamber (99) which rises accordingly when the rotation speed of the pump impeller (50) exceeds a predetermined value. A transmission for a small vehicle, wherein a pressure plate (94) cooperates with a pressure receiving plate (93) to clamp a friction clutch plate (95). 6. The transmission for a small vehicle according to claim 1, wherein the lock-up clutch (Lc ″) is automatically activated when the number of revolutions of the turbine impeller (51) exceeds a predetermined value. A transmission for a small vehicle, wherein the transmission is configured to be dependent on the number of revolutions. 7. The transmission for a small vehicle according to claim 6, wherein the lock-up clutch (Lc ″) is connected to the turbine impeller (51).
And the cylinder hole (1) of the clutch cylinder (106).
06a) and a pressurizing piston (107) slidably fitted to define a hydraulic chamber (108), and a piston return spring (urged toward the hydraulic chamber (108) for the pressurizing piston (107)). 114), means (117) for introducing oil into the hydraulic chamber (108), and friction engagement means (110-112) provided between the clutch cylinder (106) and the pump impeller (50). Turbine impeller (5
When the rotation speed of 1) becomes equal to or more than a predetermined value, the pressurizing piston (107) operates the friction engagement means (110 to 112) by the centrifugal oil pressure in the hydraulic chamber (108) which rises accordingly, and operates the clutch cylinder ( 106) and the pump impeller (5
0) A transmission for a small vehicle, wherein the transmission is connected. 8. The transmission for a small vehicle according to claim 7, wherein the clutch cylinder (106) is provided with a hydraulic chamber (10).
8) a relief hole (118) for opening the outer peripheral side to the outside;
A centrifugal valve (120) for opening the relief hole (118) when the rotation speed of the clutch cylinder (106) is less than a predetermined value, and closing the relief hole (118) when the rotation speed is equal to or more than the predetermined value; Transmission for small vehicles.