JP2001295867A - Power transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of a power transmission by constituting a rotation speed dependent type clutch of an inexpensive one-way clutch using a sprag. SOLUTION: This power transmission is provided with an input rotation speed dependent type clutch C getting into a connected state, when the rotation speed of a crankshaft 1 becomes a prescribed value or more, and transmitting the rotation torque of an input shaft 1 to a loading side. The clutch is constituted of the one-way clutch C comprising a clutch outer 20 connected to the crankshaft 1, a clutch inner 21 arranged in the clutch outer 20 inside and connected to the loading side, and a plurality of sprags 23 interposed between the clutch outer 20 and the clutch inner 21 and lock-engaged with the clutch outer 20 and the clutch inner 21, when the rotation speed of the crankshaft 1 becomes prescribed value or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission provided with an input speed-dependent clutch for transmitting a rotation torque of an input shaft to a load side when the input shaft speed exceeds a predetermined value. Related to the device.

[0002]

2. Description of the Related Art In a conventional power transmission device, as an input speed-dependent clutch, a centrifugal clutch (for example, Japanese Patent Application Laid-Open No.
No. 15131) and a shoe type in which a clutch shoe is pressed against the inner peripheral surface of a clutch drum by centrifugal force are widely used.

[0003]

However, since the conventional centrifugal clutch has a relatively large number of parts and is expensive, it is difficult to reduce the cost of the power transmission device.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has been made so that a rotational speed dependent clutch can be constituted by an inexpensive one-way clutch using sprags, thereby reducing the cost of the power transmission device. The purpose is to achieve reduction.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides an input rotating device for connecting the input shaft to a load when the rotational speed of the input shaft exceeds a predetermined value. In a power transmission device equipped with a number-dependent clutch, the clutch may include a clutch outer connected to one of an input shaft and a load side, and a clutch inner disposed inside the clutch outer and connected to the other of the input shaft and the load side. And a plurality of sprags interposed between the opposed outer peripheral surfaces of the clutch outer and the clutch inner and locked to engage with the opposed outer peripheral surface when the number of revolutions of the input shaft exceeds a predetermined value. Is a first feature. The input shaft is a crankshaft 1 in an embodiment of the present invention described later.
Corresponding to

According to the first feature, the input speed-dependent clutch can be constituted by a one-way clutch having a small number of parts and a simple structure. Therefore, the cost can be reduced by reducing the cost of the power transmission device. Can be achieved.

Further, the present invention provides, in addition to the first feature,
A second feature is that a torque buffer means for absorbing a torque shock generated when the one-way clutch is connected is provided in a transmission path on the output side of the one-way clutch. The torque buffer means corresponds to a torque converter T in an embodiment of the present invention described later.

According to the second feature, even if a torque shock occurs when the one-way clutch is engaged, the torque shock is absorbed by the buffer function of the torque buffer means, and smooth power transmission can be performed.

Further, the present invention provides, in addition to the second feature, a fluid transmission device comprising: the torque buffer means; a pump impeller connected to an output side of the one-way clutch, and a turbine impeller connected to a load side. The configuration is a third feature. The fluid transmission corresponds to a torque converter T in an embodiment of the present invention described later.

According to the third feature, the torque shock generated by the one-way clutch can be effectively absorbed by the slip between the pump impeller and the turbine impeller of the fluid transmission.

[0011]

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

FIG. 1 is a longitudinal sectional view of a power unit for a motorcycle provided with a power transmitting device of the present invention, FIG. 2 is an enlarged view of a main part of the power transmitting device, and FIG. 3 is a sectional view taken along line 3-3 in FIG. This shows the disconnected state of the input speed dependent one-way clutch),
4 is an exploded view taken along line 4-4 in FIG. 2, FIG. 5 is a perspective view of a main part of the retainer in FIG. 4, FIG. 6 is an operation explanatory view showing a half-connected state of the one-way clutch, and FIG. FIG. 8 is a sectional view corresponding to FIG. 3, showing a modification of the one-way clutch in a disconnected state, and FIG. 9 is an action explanatory view showing the connected state of the one-way clutch. is there.

First, in FIG. 1, a power unit P for a motorcycle includes a crankshaft 1 disposed in the left-right direction of a vehicle and a crankcase 2 having a pair of left and right bearings 3, 3 '.
And a transmission 5 housed in a transmission case 4 integrally provided with the crankcase 2. Crankcase 2 of crankshaft 1
At the right end protruding outside, a one-way clutch C of an input rotation speed dependent type and a torque converter T connected to the output side of the clutch C are provided. The mission 5 is connected via the device 6. The one-way clutch C and the torque converter T are covered by a case side cover 7 joined to a side surface of the crankcase 2. The crankshaft 1 is also supported by the case side cover 48 via the bearing 8.

In the above, the input speed-dependent one-way clutch C, the torque converter T, the primary reduction gear 6 and the transmission 5 constitute a power transmission device M in cooperation.

The transmission 5 includes a transmission input shaft 10 and a transmission output shaft 11 supported on the transmission case 4 in parallel with the crankshaft 1, a drive gear 12 rotatably supported on the transmission input shaft 10, and a transmission output shaft. A driven gear 13 splined to the shaft 11 and meshing with the drive gear 12, a dog clutch 14 for turning on and off the transmission input shaft 10 and the drive gear 12, and a shift device 15 for turning on and off the dog clutch 14
It is composed of

The right end of the mission input shaft 10 is
A driven gear 6b of the next reduction device 6 is connected, and a secondary reduction device 16 for driving a rear wheel (load) (not shown) is connected to a left end of the transmission output shaft 11. A kick starter gear train 17 is provided between the transmission input shaft 10 and the transmission output shaft 11.

At the left end of the crankshaft 1, a rotor 18a of a generator 18 is mounted.

The input rotation speed dependent one-way clutch C will be described in detail with reference to FIGS.

The one-way clutch C includes a clutch outer 20 for spline-connecting a boss 20b to the crankshaft 1, and a cylindrical portion 21a in the cylindrical portion 20a of the clutch outer 20.
And a clutch inner 21 which is rotatably supported on the crankshaft 1 via a bearing 22, a cylindrical portion 20 a of the clutch outer 20 and a clutch inner 2.
A large number of sprags 23, 23... Arranged in the circumferential direction between opposing peripheral surfaces of one cylindrical portion 21a, a retainer 24 for holding these sprags 23, 23. Radially outward, that is, clutch outer 2
And a return spring 25 that urges the cylinder portion 20a toward the zero.

As shown in FIGS. 3 and 4, the return spring 25 bends the elastic wire rod into a circular shape and urges all the sprags 23, 23,... Has become. Each sprag 23 is provided with a spring groove 26 with which the return spring 25 is engaged. This spring groove 2
6 is a circumferential groove 2 which can be fitted to the outer peripheral surface of the return spring 25;
6a and a radial groove 26b bent radially outward from the front end (front side in the clutch outer rotation direction R) of the circumferential groove 26a.

Each sprag 23 has a first engaging surface 27 facing the inner peripheral surface of the cylindrical portion 20a of the clutch outer 20.
And a second engagement surface 28 facing the outer peripheral surface of the clutch inner 21. The first engagement surface 27 is formed in an arc shape so as to be able to roll on the inner peripheral surface of the cylindrical portion 20a of the clutch outer 20, and the second engagement surface 28 is substantially L-shaped by bending an intermediate portion along the spring groove 26. It is shaped like a letter. The first and second engagement surfaces 2 facing each other in a direction along the circumferential groove 26a
The distance L1 between the clutch surfaces 7 and 28 is greater than the distance L2 between the opposed peripheral surfaces of the cylindrical portions 20a and 21a of the clutch outer 20 and the clutch inner 21, and the two engaging surfaces 27 and 27 facing each other in the direction along the radial groove 26b. 28 is set smaller than the distance L2 between the opposing peripheral surfaces.

The retainer 24 is formed by bending a wire zigzag and bending the wire in a circular shape. The retainer 24 alternately passes between a large number of sprags 23, 23.
The arrangement intervals of the sprags 23 are regulated. Both ends of the wire constituting the retainer 24 are
After being abutted against each other and bent outward in the radial direction to form a detent claw 29, this detent claw 29 is inserted into a detent groove 30 provided on the inner peripheral surface of the cylindrical portion 20 a of the clutch outer 20. By doing so, the retainer 24
Are adapted to rotate together with the clutch outer 20 with all sprags 23, 23.

Further, each sprag 23 is provided with a lightening hole 31 at a position offset from the center of the sprag 23 toward the groove 26b in the radial direction.
Is set at a point offset from the center of the sprag 23 to the side opposite to the radial groove 26b.

As shown in FIG. 2, a pair of side plates 32, 32 'facing the left and right sides of all sprags 23, 23,. Direction movement is restricted.

The cylindrical portion 21a of the clutch inner 21
Is disposed so as to surround the boss 20b of the clutch outer 20, and a one-way clutch 35 for transmitting a back load is interposed between the cylindrical portion 21a and the opposing peripheral surface of the boss 20b. Thereby, transmission of the back load from the clutch inner 21 to the clutch outer 20 side becomes possible.

Next, the torque converter T will be described with reference to FIGS.

The torque converter T is disposed closer to the crankcase 2 than the input speed-dependent one-way clutch C. The torque converter T includes a pump impeller 40 integrally connected to the clutch inner 21, a turbine impeller 41 disposed opposite to the pump impeller 40, and a
It has a general configuration including a stator impeller 42 disposed between 0 and 41, and the inside thereof is filled with hydraulic oil.

The stator impeller 42 is connected via a freewheel 45 to a stator shaft 44 which is rotatably fitted to the outer periphery of the crankshaft 1 via a bearing 43.
The stator shaft 44 has a flange 44 formed at the left end thereof.
a is fixed to the crankcase 2 with bolts 46.

A turbine shaft 50 integrally connected to the turbine impeller 41 is supported by a stator shaft 44 via a bearing 47. At the left end of the turbine shaft 50, a drive gear 6a of the primary reduction gear 6 is provided. It is formed integrally. Therefore, primary reduction gear 6 is arranged between crankcase 2 and torque converter T.

The pump impeller 40 has a turbine impeller 4
A side cover 48 that covers the back of the unit 1 is integrally connected,
A one-way clutch 49 for transmitting a back load is interposed between the side cover 48 and the stator shaft 44. This enables transmission of the back load from the turbine shaft 50 to the pump impeller 40 side.

Next, the operation of this embodiment will be described.

In the input rotation speed dependent one-way clutch C, as shown in FIG. 3, the return spring 25 normally engages with the first engaging surface 27 while engaging with the circumferential groove 26a of each sprag 23. The second engagement surface 28 is separated from the outer peripheral surface of the cylindrical portion 21 a of the clutch inner 21 by pressing against the inner peripheral surface of the cylindrical portion 20 a of the outer 20. This is the non-connected state of the one-way clutch C. When the engine E is idling, this state is maintained, and the rotation of the clutch outer 20 is not transmitted to the clutch inner 21.

When the rotation speed of the crankshaft 1 is increased to start the vehicle, the clutch outer 20 and the sprag 2
The rotation speed of 3, 23 ... increases, and the center of gravity G of each sprag 23
The sprags 23 roll on the inner peripheral surface of the cylindrical portion 20a of the clutch outer 20 so as to move the center of gravity G outward in the radial direction against the repulsive force of the return spring 25, As shown in FIG. 6, the portion at the distance L1 is raised, the second engagement surface 28 is lightly brought into contact with the outer peripheral surface of the cylindrical portion 21a of the clutch inner 21, and the contact surfaces of the clutch outer 20 are slipped appropriately. The transmission of the rotational torque to the clutch inner 21 starts. This state is a semi-connected state.

When the rotation speed of the crankshaft 1 further increases,
As the centrifugal force applied to the center of gravity G of each sprag 23 further increases, each sprag 23 further rises the portion of the distance L1, so that the first engagement surface 27 is connected to the inner peripheral surface of the cylindrical portion 20a of the clutch outer 20, The second engagement surface 28 enters the lock engagement state with the outer peripheral surface of the cylindrical portion 21a of the clutch inner 21. This state is the connection state, and the clutch outer 2
0 to the clutch inner 2 via the sprags 23, 23 ...
1 can be transmitted without loss.

When the rotation of the crankshaft 1 is transmitted to the pump impeller 40 in accordance with the connection state of the input speed-dependent one-way clutch C, the working oil in the torque converter T
The rotation torque of the pump impeller 40 is circulated through the torque converter T from the outer peripheral side of the pump impeller 40 to the inner peripheral side of the pump impeller 40 through the turbine impeller 41 and the stator impeller 42 in order. The power is transmitted to the turbine impeller 41, and the primary reduction gear 6 is driven from the turbine shaft 50. During this time, if a torque amplifying action occurs between the pump impeller 40 and the turbine impeller 41, a corresponding reaction force is applied to the stator impeller 42, and the stator impeller 4
2 is supported on the fixed stator shaft 44 by the locking action of the freewheel 45.

When the primary reduction gear 6 is driven from the stator shaft 44, the driving torque is transmitted to the transmission input shaft 10 of the transmission 5. At this time, dog clutch 1
When the transmission 4 is in the ON position, the driving torque of the transmission input shaft 10 is transmitted to the secondary reduction gear 16 via the driving and driven gears 12 and 13 and the transmission output shaft 11 in that order, and is transmitted to the rear wheel of the motorcycle (not shown). Will be driven.

Since the half-connected state of the input speed-dependent one-way clutch C is shorter than that of a general centrifugal clutch, a relatively large torque shock occurs when the clutch enters the connected state. In this case, the torque converter T slides between the pump impeller 40 and the turbine impeller 41 to exhibit a torque buffering function and absorbs the torque shock. Therefore, even when the one-way clutch C having a short half-connected state is used, a smooth start according to the rotation speed of the crankshaft 1 can be performed.

In addition, the one-way clutch C depending on the input rotation speed includes a clutch outer 20, a clutch inner 21,
Since the sprag 23 and the return spring 25 are components,
The number of parts is very small as compared with the centrifugal clutch, and the configuration is simple. Therefore, the cost reduction of the power transmission device M can be largely achieved by reducing the cost.

When the back load is transmitted from the primary reduction gear 6 to the stator shaft 44 during deceleration of the vehicle, the one-way clutch 49 is brought into the connected state, and the turbine shaft 50 and the side cover 48 are directly connected. The back load is transmitted from the turbine shaft 50 to the pump impeller 40 via the side cover 48, and further to the clutch inner 21 of the input rotation speed dependent one-way clutch C. Then, the one-way clutch 35 is also in the connected state, so the backload transmitted to the clutch inner 21 is transmitted to the crankshaft 1 via the clutch outer 20. Therefore, no slippage occurs between the turbine impeller 41 and the pump impeller 40, and no slippage occurs between the clutch inner 21 and the clutch outer 20, so that a good engine braking effect can be obtained.

Next, with reference to FIGS. 8 and 9, a modified example of the input rotational speed dependent one-way clutch C will be described.

The one-way clutch C includes a cylindrical portion 20a of the clutch outer 20 and a cylindrical portion 2 of the clutch inner 21.
1a, an inner ring 51 and an outer ring 52 surrounding the inner ring 51 are provided. The inner ring 51 and the outer ring 52 have a large number of holding holes 53 and 54, respectively.
The radially opposite ends of a large number of cocoon-shaped sprags 55, 55 interposed between the cylindrical portions 20a, 21a of the clutch outer 20 and the clutch inner 21, are held by the 3, 54 in a swingable manner. The inner ring 51 and the outer ring 52 give the sprags 55, 55... An inclined posture at the time of relative rotation of one of them, and the sprags 55, 55. On the other hand, when the inner ring 51 and the outer ring 52 rotate relative to each other in a disengaged state and a non-engaged state (disconnected state, see FIG. 8),
By giving the sprags 55, 55 ... an upright posture, the cylindrical portions 20a, 21a of the clutch outer 20 and the clutch inner 21 are provided.
(See FIG. 9).

The outer ring 52 is provided with a detent claw 56 projecting radially outward from the outer peripheral surface thereof, and this is engaged with a detent groove 57 on the inner surface of the cylindrical portion 20 a of the clutch outer 20. Therefore, the outer ring 52 is always
, 55 and the inner ring 51 are rotated together with the clutch outer 20.

A sprag 5 is provided between the inner ring 51 and the outer ring 52.
An elastic ring 63 for elastically connecting the 5, 55...

A centrifugal weight 58 is provided on the inner ring 51.
9, the weight portion 58a is swingable in the radial direction, and a long hole 6 provided in the centrifugal weight 58 is provided.
The connection pin 61 fixed to the outer race 52 is fitted into the outer ring 52.
When the centrifugal weight 58 swings its weight portion 58a inward in the radial direction, the inner ring 51 and the outer ring 52 rotate relative to each other in a direction in which the sprags 55, 55 ... are inclined. By swinging outward in the radial direction, the sprag 55,
55, the inner ring 51 and the outer ring 52
Are designed to rotate relative to each other. A return spring 62 for urging the centrifugal weight 58 so that the weight portion 58a faces inward in the radial direction is mounted on the pivot 59.

The other structure is the same as that of the above embodiment.

In the one-way clutch C, the centrifugal weight 58 is normally swung in the radial direction by the biasing force of the return spring 62, as shown in FIG. 52, sprags 55, 55
Are held in the inclined posture, so that the one-way clutch C is in the disconnected state. When the engine E is idling, this state is maintained, and the rotation of the clutch outer 20 is not transmitted to the clutch inner 21. .

When the rotational speed of the crankshaft 1 is increased to start the vehicle, the centrifugal weight 58 is increased with the increase in the rotational speed of the clutch outer 20, outer ring 52, inner ring 51, sprags 55, 55, and centrifugal weight 58. Because the centrifugal force applied to the weight portion 58a of the centrifugal force increases, the centrifugal weight 58 swings around the pivot 59 against the repulsive force of the return spring 62 so as to move the weight portion 58a outward in the radial direction. The sprags 55 and 55 are rotated relative to the inner ring 51 and the outer ring 52 in the direction opposite to the previous time.
, And the one-way clutch C is connected. Therefore, the sprag 5
Power can be transmitted to the clutch inner 21 via the 5, 55,.

In this case as well, the period of the semi-connected state during the transition from the disconnected state to the connected state is extremely short, and when the connected state is established, a torque shock occurs. To achieve a smooth start of the vehicle.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the gist of the present invention. For example, the torque converter T can be replaced with a fluid coupling including a pump impeller and a turbine impeller, or can be replaced with another torque damper using a spring.

[0050]

As described above, according to the first feature of the present invention, the input speed-dependent clutch can be constituted by a simple one-way clutch having a small number of parts and a simple structure. Thus, the cost of the power transmission device can be reduced.

According to the second feature of the present invention, the one-way clutch is provided with a torque buffer for absorbing a torque shock generated when the one-way clutch is connected in the transmission path on the output side of the one-way clutch. Even if a torque shock occurs when the clutch is connected, the shock is absorbed by the buffer function of the torque buffer means, and smooth power transmission is enabled.

According to a third feature of the present invention, the torque buffer means is constituted by a fluid transmission device including a pump impeller connected to the output side of the one-way clutch and a turbine impeller connected to the load side. Therefore, the torque shock generated by the one-way clutch can be effectively absorbed by the slip between the pump impeller and the turbine impeller.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a power unit for a motorcycle including a power transmission device of the present invention.

FIG. 2 is an enlarged view of a main part of the power transmission device.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2 (showing a disconnected state of the input speed-dependent one-way clutch).

FIG. 4 is a development view taken along line 4-4 of FIG. 2;

FIG. 5 is a perspective view of a main part of the retainer in FIG. 4;

FIG. 6 is an operation explanatory view showing a half-connected state of the one-way clutch.

FIG. 7 is a sectional view corresponding to FIG. 3, showing a modification of the one-way clutch in a disconnected state;

FIG. 8 is a sectional view corresponding to FIG. 3, showing a modification of the one-way clutch in a disconnected state.

FIG. 9 is an operation explanatory view showing a connected state of the one-way clutch.

[Explanation of symbols]

C: Input rotation speed dependent one-way clutch M: Power transmission device T: Torque buffering means, fluid transmission device (torque converter) 1 .... Input shaft (crank) Shaft) 20: clutch outer 21: clutch inner 23: sprag 55: sprag

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuichi Tawarada 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3D039 AA02 AA03 AA04 AB04 AC06 AC13 AC21 AC37 AD03 AD06

Claims (3)

[Claims] An input speed-dependent clutch (C) that is connected when the speed of the input shaft (1) exceeds a predetermined value and transmits the torque of the input shaft (1) to the load side. In the power transmission device, the clutch is connected to a clutch outer (2) connected to one of the input shaft (1) and the load side.
0) and this clutch outer (20)
The input shaft (1) is interposed between the clutch inner (21) connected to the other of the load side and the outer peripheral surfaces of the clutch outer (20) and the clutch inner (21). A power transmission device comprising a one-way clutch (C) comprising a plurality of sprags (23, 55) which are locked and engaged with the opposed peripheral surface when the value exceeds the value. 2. The power transmission device according to claim 1, wherein
The transmission path on the output side of the one-way clutch (C) is provided with a torque buffer (T) for absorbing a torque shock generated when the clutch (C) is connected.
Power transmission device. 3. The power transmission device according to claim 2, wherein
A fluid transmission device (T) including a torque control means including a pump impeller (40) connected to the output side of the one-way clutch (C) and a turbine impeller (41) connected to the load side.
A power transmission device characterized by comprising: