JPH11291786A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To intermittently operate a clutch with small operating force. SOLUTION: This device is equipped with power transmission members 23 and 25 disposed to a power transmission system for the front wheel side or the rear wheel side of a four wheel drive vehicle, a clutch member 27 connected with the power transmission member 25 by means of the engagement of a connection part in such a way as to be freely moved, a mesh clutch 29 interposed between the clutch member 27 and the power transmission member 23, and with an electromagnet 31 and a return spring 33 which intermittently connect the mesh clutch 29 by letting the clutch member 27 be moved and operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power transmission device used for a four-wheel drive vehicle.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 58-89425 discloses FIG.
Such a power transmission device 201 is described.

[0003] The power transmission device 201 comprises a front wheel drive base.
This is a transfer for a four-wheel drive vehicle.

[0004] The power transmission device 201 has an input shaft 20.
3. High-speed / low-speed switching mechanism 205, front differential 20
7, front axles 209, 211, countershaft 213, direction changing gear set 215, intermediate shaft 217, 2-4 switching mechanism 219,
It comprises an output shaft 221 and the like.

The driving force of the engine is transmitted from a transmission via an input shaft 203 to a high-speed / low-speed switching mechanism 205.
Is transmitted to the front differential 207 after being switched to high speed or low speed, and is distributed to the left and right front wheels via the front axles 209 and 211.

The driving force of the engine is supplied from the high-speed / low-speed switching mechanism 205 to the countershaft 213, the direction changing gear set 215,
It is transmitted to the 2-4 switching mechanism 219 via the intermediate shaft 217.

[0007] When the 2-4 switching mechanism 219 is connected,
The driving force of the engine is transmitted to the rear differential via the output shaft 221 and is distributed to the left and right rear wheels via the rear axle, and the vehicle enters a four-wheel drive state.

When the connection of the 2-4 switching mechanism 219 is released, the rear wheel side is disconnected from the engine, and the vehicle enters a two-wheel drive state of front wheel drive.

The 2-4 switching mechanism 219 engages and disengages with the spline teeth 223 and 225 provided on the outer periphery of the intermediate shaft 217 and the output shaft 221, respectively, by moving in the axial direction. And a coupling sleeve 227.

[0010]

In the above four-wheel drive vehicle, a viscous fluid coupling (a viscous coupling) for transmitting a driving force between the output shaft 221 and the rear differential by, for example, shear resistance of the viscous fluid, Alternatively, if a speed-sensitive coupling that operates in response to the differential rotation speed is installed, such as a dual pump, the rear wheel is driven through these couplings only when the front wheels idle. Power is transmitted.

In addition, when braking, a greater load is applied to the front wheels than for the rear wheels, and in a front-wheel drive-based four-wheel drive vehicle, a greater load is applied to the front wheels when starting or accelerating, so that the front tires are used first. And the tire diameter becomes smaller than that of the rear wheel tire, so that a difference occurs in the tire diameter between the front and rear wheels.

The front wheel having a reduced tire diameter rotates faster than the rear wheel having a large diameter, and the differential rotation between the front and rear wheels thus generated activates a speed-sensitive coupling. Therefore,
In this four-wheel drive vehicle, the front wheels on the high-speed rotation side run while always braking the rear wheels on the low-speed rotation side via the speed-sensitive coupling, and the fuel efficiency of the engine is greatly reduced.

Further, in the case of a sharp turn in which the differential rotation of the speed-sensitive coupling becomes large, the transmission force becomes a restraining force that hinders the differential rotation between the front and rear wheels, and a tight corner breaking phenomenon occurs. Occurs and the behavior of the vehicle body becomes unstable.

Further, the viscous fluid coupling has a transmission torque capacity, and a power transmission system which receives a driving force via the viscous fluid coupling has design durability set in accordance with the transmission torque capacity. .

However, the viscous fluid coupling has a hump phenomenon in which one side and the other side are fixed. When this hump phenomenon occurs, a large torque exceeding the transmission torque capacity is transmitted, and the durability of the power transmission system is increased. May decrease.

In such a case, 2-4 switching mechanism 2
By disconnecting the rear wheel side (speed-sensitive coupling) by disconnecting the connection 19, a reduction in fuel consumption, a tight corner breaking phenomenon, a reduction in durability, and the like are prevented.

However, when disconnecting the rear wheel,
Since the torque due to the differential rotation between the front and rear wheels is applied to the 2-4 switching mechanism 219, the coupling sleeve 227 is unlikely to come off from the spline teeth 225 even if the connection is to be released in this state, and the connection is smoothly released. Is difficult.

In order to smoothly release the connection of the 2-4 switching mechanism 219, the actuator for moving the coupling sleeve 227 needs to be large and strong.

However, when the size of the actuator is increased,
The device is large and heavy, and the fuel consumption is further deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power transmission device capable of intermittently operating a clutch with a small operating force.

[0021]

According to a first aspect of the present invention, in a four-wheel drive vehicle, a power transmission system for a front wheel is provided.
A pair of power transmission members arranged in the rear wheel side power transmission system, a clutch member movably connected to one of the power transmission members by a connection portion, and between the clutch member and the other power transmission member. A clutch provided, and a moving operating means for moving and operating the clutch member to connect and disconnect the clutch, wherein the clutch is formed of meshing teeth formed to face each other and having an axial tooth length, Is a meshing clutch for intermittently driving force by moving the clutch member in the axial direction.

When the dog clutch is engaged, the vehicle is driven in a four-wheel drive state, and the running performance on rough roads and the stability of the vehicle body are improved. In addition, when the engagement clutch is released, the vehicle enters a two-wheel drive state, and the fuel efficiency of the engine is improved.

Further, the power transmission device of the first aspect is different from the conventional example in which the driving force is intermittently driven by engagement and disengagement of the spline teeth.
The driving force is intermittently driven by a dog clutch.

The meshing clutch is easy to increase in diameter, and can reduce the load per unit area by increasing the number of meshing teeth as compared with spline teeth having the same diameter. , The clutch member can be moved and operated with a small operating force, and the driving force can be cut off smoothly.

Therefore, it is not necessary to increase the size of the moving operation means, and it is possible to prevent the accompanying increase in the size and weight of the power transmission device and a decrease in fuel efficiency.

Further, since the disengagement of the dog clutch is easy, even if a viscous fluid coupling is arranged in the power transmission system on the dog clutch side, for example, when there is a difference in tire diameter between the front and rear wheels. When necessary, such as when the viscous fluid coupling is humped during a sharp turn, the engagement of the meshing clutch can be smoothly released at any time, resulting in lower fuel consumption, tight corner breaking phenomenon, and durability. Can be prevented beforehand.

According to a second aspect of the present invention, there is provided the power transmission device according to the first aspect, wherein the moving operation means biases the clutch member in a direction of releasing the engagement of the meshing clutch, and includes a biasing member. An actuator for moving the clutch member against the force and connecting the dog clutch is provided, and the same effects as those of the first aspect are obtained.

In a four-wheel drive vehicle, the traveling time in the two-wheel drive state is generally longer than the travel time in the four-wheel drive state. Therefore, in this configuration in which the meshing clutch is connected by the operating force of the actuator, The actuator can be stopped in the two-wheel drive state where the running time is long, and the fuel efficiency is greatly improved.

According to a third aspect of the present invention, in the power transmission device according to the first aspect, the moving operation means includes an urging member for moving the clutch member in a connecting direction of the dog clutch, and a urging force of the urging member. An actuator for moving the clutch member in opposition to release the engagement of the meshing clutch is provided, and the same effect as the configuration of claim 1 is obtained.

The invention according to claim 4 is the invention according to claims 1 to 3.
The power transmission device according to any one of the above, wherein the meshing teeth of a connecting portion that connects the one power transmission member and the clutch member form a cam that operates by receiving a transmission torque,
The clutch member is pressed toward the meshing position of the meshing clutch by the cam thrust force,
An effect equivalent to any one of claims 1 to 3 is obtained.

In addition, a cam formed by giving a cam angle to the meshing teeth connecting the power transmission member and the clutch member operates by receiving the transmission torque, and the cam thrust force pushes the clutch member toward the meshing position. Thus, a self-locking function of the dog clutch is obtained.

Even if vibration is applied during traveling, the clutch member is held at the meshing position by this self-locking function. Therefore, disconnection of the meshing clutch against the driver's intention is prevented, and The play of the clutch member is prevented, and the vehicle can run in a stable four-wheel drive state.

This self-locking function is particularly useful when the meshing clutch is connected by a spring or an actuator having a small operating force.

[0034] The invention of claim 5 is the invention of claims 1 to 3.
Wherein each of the meshing teeth of the meshing clutch forms a cam that operates by receiving a transmission torque, and when the transmission torque exceeds a predetermined value, the meshing clutch is driven by the cam thrust force. The clutch member is retracted to the meshing release position, and an effect equivalent to any one of claims 1 to 3 is obtained.

In addition, a cam is formed by giving a cam angle to the meshing teeth of the meshing clutch, and when the transmission torque exceeds a predetermined value, the clutch member is retracted to the meshing release position of the meshing clutch by the cam thrust force. Thereby, a torque limiter function of interrupting a torque equal to or more than a predetermined value is obtained.

For example, if the torque limiter function is set so as to operate below the hump torque of the viscous fluid coupling, the power transmission system on the viscous fluid coupling side is protected from excessive hump torque, and the durability is greatly improved. .

The torque limiter function includes a spring,
Alternatively, it is particularly effective when the meshing clutch is connected by an actuator having a small operating force.

The invention of claim 6 is the invention of claims 2 to 5
The power transmission device according to any one of claims 1 to 3, wherein the actuator comprises an armature and an electromagnet for attracting the armature, and the clutch member is the armature. An effect equivalent to any one of the fifth aspect is obtained.

In addition, an actuator using an electromagnet does not require a complicated oil passage and a seal member such as a hydraulic actuator, so that the structure is simple and the cost is low. In addition to the high packageability, it is easy to incorporate.

Further, as described above, the effect of the present invention in which the clutch member can be smoothly moved with a small operating force is the effect of this configuration using an electromagnet having a relatively small operating force as an actuator. ,high.

Further, since the operating force is small, the power consumption of the electromagnet is small, and the load on the battery is light, so that the decrease in the fuel consumption of the engine is reduced.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. This embodiment corresponds to claims 1, 2,
1 and 3 show a 2-4 switching device 1 which is a power transmission device of this embodiment. In addition,
The upper part of FIGS. 1 to 4 corresponds to the front of a four-wheel drive vehicle in which the 2-4 switching device 1 is used, and members and the like without reference numerals are not shown.

This 2-4 switching device 1 is used for transfer of a front-wheel drive-based four-wheel drive vehicle, as in the conventional example of FIG.

This transfer includes a driving force input shaft, a front differential, left and right front axles, a direction changing gear set, a drive pinion shaft 3, a 2-4 switching device 1, and an output shaft 5.
It is composed of

The driving force of the engine is transmitted from the transmission to the front differential via the input shaft, and is distributed from the front differential to the left and right front wheels via the front axle.

The direction changing gear set includes a bevel gear fixed to the input shaft and a bevel gear 7 formed on the drive pinion shaft 3. The rotation of the input shaft is changed in direction by the direction changing gear set, and the drive pinion shaft is rotated. Rotate 3

The output shaft 5 is connected to a propeller shaft via a joint, and this propeller shaft is connected to the rear differential via another joint and a speed-sensitive viscous fluid coupling.

When the 2-4 switching device 1 is connected, the driving force of the engine is transmitted from the 2-4 switching device 1 to the rear differential via the output shaft 5, the joint, the propeller shaft and the viscous fluid coupling, and from the rear differential to the rear axle. , And is distributed to the left and right rear wheels, and the vehicle enters a four-wheel drive state.

When the connection of the 2-4 switching mechanism 1 is released, the rear wheel side is disconnected from the engine, and the vehicle enters a front-wheel drive two-wheel drive state.

The drive pinion shaft 3 is supported on a transfer case 13 via bearings 9 and 11.

The output shaft 5 is supported by a transfer case 13 via a bearing 15, and the rear end of the drive pinion shaft 3 penetrates into the hollow portion of the output shaft 5, via a bearing 17. And are centered on each other.

The output shaft 5 protrudes rearward from the transfer case 13, and a seal 19 for preventing oil leakage is arranged between them. A flange 21 is formed at the rear end of the output shaft 5.
Is connected to the joint on the propeller shaft side.

2-4 The switching device 1 includes a power transmission member 2
3, 25; clutch member 27 (armature); meshing clutch 29; electromagnet 31 (actuator);
Spring 33 (biasing member).

The power transmission member 23 is spline-connected to the drive pinion shaft 3 and is positioned by a retaining ring 35. The power transmission member 25 is spline-connected to the output shaft 5.

As shown in FIGS. 2 and 4, the clutch member 27 and the power transmission member 25 have meshing teeth 37 and 39 (connecting portions).
Are provided, and the clutch member 27 is connected to the power transmission member 25 in an axially movable manner by meshing of the meshing teeth 37 and 39.

As shown in FIGS. 2 and 4, the meshing clutch 29 includes a number of meshing teeth 41 and 43 provided on the power transmission member 23 and the clutch member 27, respectively. These meshing teeth 41 and 43 have a tooth length formed in the axial direction.

The meshing clutch 29 is, as shown in FIG.
When the clutch member 27 moves forward, the meshing teeth 41,
When the clutch member 27 moves rearward as shown in FIG. 4, the meshing teeth 41 and 43 are disengaged and the connection is released.

The electromagnet 31 includes the yoke 45 and the electromagnetic coil 4.
7 and the yoke 45 is the transfer case 13.
It is fixed to the inner circumference of. The power transmission member 23 is provided with a notch 49, and an appropriate air gap is provided between the power transmission member 23 and the yoke 45 to form a magnetic circuit of the electromagnet 31. . Electric power is supplied to the electromagnetic coil 47 from a battery mounted on the vehicle.

The clutch member 27 is an armature of the electromagnet 31. When the electromagnet 31 is excited, the clutch member 27 is attracted and moves forward, and the meshing clutch 29 meshes as shown in FIG. The device 1 is connected.

When the 2-4 switching device 1 is connected, the vehicle enters the four-wheel drive state, and the running performance on rough roads and the like is improved.

The return spring 33 is disposed between the yoke 45 of the electromagnet 31 and the clutch member 27.
The clutch member 27 is urged toward the side where the engagement clutch 29 is disconnected.

When the excitation of the electromagnet 31 is stopped, the return spring 33 moves the clutch member 27 backward,
As shown in FIG. 4, the engagement of the engagement clutch 29 is released, and the connection of the 2-4 switching device 1 is released.

When the connection of the 2-4 switching device 1 is released, the vehicle enters the two-wheel drive state, and the fuel efficiency of the engine is improved.

Thus, the 2-4 switching device 1 is configured.

As described above, the 2-4 switching device 1
Unlike the conventional example in which the driving force is interrupted by engaging and disengaging the spline teeth, the driving force is interrupted by the meshing clutch 29.

The meshing clutch 29 can be easily formed to have a large diameter, and the load per unit area can be reduced by increasing the number of meshing teeth 41 and 43 as compared with spline teeth having the same diameter. In this state, the clutch member 27 can be moved by the relatively small urging force of the return spring 33 to release the engagement and disconnect the rear wheel side.

Therefore, when there is a difference in tire diameter between the front and rear wheels, when a sharp turn is performed, or when a large torque is applied such as when the viscous fluid coupling on the rear wheel is humped, 2-4 Since the switching device 1 can smoothly release the connection, it is possible to release the connection at any time under these circumstances, such as a decrease in fuel consumption, a tight corner breaking phenomenon, and a decrease in durability. Can be prevented beforehand.

Further, the configuration in which the meshing clutch 29 is connected by the electromagnet 31 allows the electromagnet 31 to be stopped in the two-wheel drive state occupying most of the traveling time, and the operating force of the meshing clutch 29 is reduced. Since the size of the electromagnet 31 is small, the power consumption of the electromagnet 31 is small, and the burden on the battery and the decrease in engine fuel efficiency are reduced accordingly.

Since the operating force is small, the electromagnet 3
1 does not need to be large, and the 2-4 switching device 1 is prevented from becoming large and heavy.

The electromagnet 31 does not require a complicated oil passage and a seal member such as a hydraulic actuator. Is high, so it is easy to incorporate.

Next, the second embodiment of the present invention will be described with reference to FIGS.
An embodiment will be described. This embodiment is defined in claims 1, 3, and 6.
FIGS. 5 and 7 show a 2-4 switching device 51 which is a power transmission device of this embodiment. The upper part of FIGS. 5 to 8 corresponds to the front of a four-wheel drive vehicle in which the 2-4 switching device 51 is used, and members and the like without reference numerals are not shown.

The 2-4 switching device 1 of the first embodiment is configured to be connected by the electromagnet 31 and to be disconnected by the return spring 33. On the contrary, are connected by a shift spring 53 and are released by the electromagnet 31.

The 2-4 switching device 51 is arranged in a transfer of a front-wheel drive four-wheel drive vehicle using the 2-4 switching device 1 of the first embodiment.

This transfer comprises an input shaft for driving force, a front differential, left and right front axles, a direction changing gear set, a drive pinion shaft 3, a 2-4 switching device 51, an output shaft 5, and the like.

The 2-4 switching device 51 includes the power transmission members 23 and 25, the clutch member 27, the electromagnet 31, the shift spring 53 (biasing member), the meshing clutch 55, and the like.

As shown in FIGS. 6 and 8, the power transmission member 23 and the clutch member 27 have meshing teeth 57 and 59 (connecting portions).
Are provided, and the clutch member 27 is connected to the power transmission member 23 in an axially movable manner by meshing of the meshing teeth 57 and 59.

The meshing clutch 55 is composed of a number of meshing teeth 61 and 63 provided on the clutch member 27 and the power transmission member 25, respectively, as shown in FIGS. In addition, these meshing teeth 61 and 63 are formed so that the tooth height is in the axial direction.

As shown in FIG. 6, the meshing clutch 55
When the clutch member 27 moves rearward, the meshing teeth 61,
When the clutch member 27 moves forward as shown in FIG. 8, the meshing teeth 61 and 63 are disengaged and the connection is released.

The shift spring 53 serves as a yaw for the electromagnet 31.
The clutch member 27 is disposed between the clutch 45 and the clutch member 27, and urges the clutch member 27 toward the coupling side of the dog clutch 55.

When the excitation of the electromagnet 31 is stopped, the clutch member 27 is moved rearward by the biasing force of the shift spring 53, and as shown in FIG. Becomes a four-wheel drive state.

When the electromagnet 31 is excited, the clutch member 27 is attracted and moves forward, and the engagement of the engagement clutch 55 and the 2-4 switching device 51 are performed as shown in FIG.
Is released, and the vehicle enters the two-wheel drive state.

Thus, the 2-4 switching device 51 is configured.

The 2-4 switching device 51 is configured so that the driving force is intermittently driven by the meshing clutch 55, and the meshing clutch 55 can reduce the load per unit area of the meshing teeth 61 and 63. On the other hand, even when torque is applied, the clutch member 27 can be moved with a small operating force to disconnect the rear wheel side.

Therefore, when there is a difference in tire diameter between the front and rear wheels, when a sharp turn is made, or when a large torque is applied such as when the viscous fluid coupling on the rear wheel is humped, 2-4 switching is performed. The device 51 can smoothly release the connection, and can prevent a reduction in fuel consumption, a tight corner breaking phenomenon, a reduction in durability, and the like.

Further, since the operating force of the dog clutch 55 is small and the electromagnet 31 does not need to be large,
The size and weight of the (-4) switching device 51 are prevented.

Further, the electromagnet 31 does not require a complicated oil passage and a seal member such as a hydraulic actuator, and has a simple structure. Therefore, the electromagnet 31 is low in cost and has high packaging properties. Easy to incorporate.

Next, FIG. 9 and FIG. 10 show the third embodiment of the present invention.
An embodiment will be described.

This embodiment has the features of claims 1, 2, 4, and 6, and the 2-4 switching device 5 of the second embodiment.
1 is an example in which the connecting portion between the power transmission member 23 and the clutch member 27 is changed.

As shown in FIG. 9 and FIG.
And the clutch member 27 are provided with meshing teeth 65 and 67 (connecting portions), respectively.
The power transmission member 2 is formed by the meshing of the meshing teeth 65 and 67.
5 is connected so as to be movable in the axial direction.

A cam angle α is given to each of the meshing teeth 65 and 67, and a cam 69 is formed. The cam thrust force Fα acts in the same direction as the biasing force F of the shift spring 53, and biases the clutch portion 27 in the direction in which the clutch 55 engages.

As shown in FIG. 9, while the engagement of the meshing clutch 55 is released and the transmission torque is not applied to the clutch portion 27, the cam 69 does not operate, but when the meshing clutch 55 meshes as shown in FIG. 65, 6
7, a driving torque is applied to operate the cam 69, and the cam thrust force Fα assists the urging force F of the shift spring 53 to strengthen the engagement of the engagement clutch 55.

Thus, a self-locking function is obtained.

Even if vibrations during traveling are received, the clutch member 27 is held at the meshing position by this self-locking function, so that disconnection of the meshing clutch 55 against the driver's intention is prevented. In addition, since the backlash of the clutch member 27 is prevented, the vehicle can run in a stable four-wheel drive vehicle state.

The self-locking function is performed when the meshing clutch 55 is connected by a spring (shift spring 53) as in the 2-4 switching device 51 of the second embodiment, or the operating force is increased. This is particularly useful in the case of a power transmission device configured to engage and operate the dog clutch with an actuator having a small size.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.

This embodiment is described in claims 1, 3, 4, 5, and 6.
It has the following features. This embodiment is an example in which the meshing clutch 55 between the clutch member 27 and the power transmission member 25 is replaced with a meshing clutch 71 in the third embodiment.

As in the third embodiment, the power transmission member 23
A cam 69 is formed between the clutch member 27 and the cam thrust force Fα. The cam thrust force Fα acts in the same direction as the biasing force F of the shift spring 53 that biases the clutch portion 27 in the meshing direction of the meshing clutch 71. I have.

As shown in FIGS. 11 and 12, the meshing clutch 71 is composed of a large number of meshing teeth 73 and 75 provided on the clutch member 27 and the power transmission member 25, respectively. , 75 have a tooth height formed in the axial direction.

A cam angle β is given to each of the meshing teeth 73 and 75 to form a cam 77. The cam thrust force Fβ acts in a direction opposite to the biasing force F of the shift spring 53 and the cam thrust force Fα of the cam 69.

Further, the cam angle β> cam angle α.

As shown in FIG. 11, when the engagement clutch 71 is engaged by the urging force F of the shift spring 53, a transmission torque is applied to the cam 69 and the cam 77. At this time, the sum of the urging force F of the shift spring 53 and the cam thrust force Fα of the cam 69 is applied to the clutch member 27 in the engagement direction of the engagement clutch 71, and the cam thrust force Fβ of the cam 77 is applied in the opposite direction.

The cam angle α of the cam 69 and the cam angle β of the cam 77
When the transmission torque reaches a predetermined value, the cam thrust force Fβ
Is set to be equal to the sum of the urging force F and the cam thrust force Fα.

Therefore, when the transmission torque exceeds a predetermined value,
Fβ> F + Fα, and the clutch member 27 retreats to the disengagement position of the meshing clutch 71 by the cam thrust force Fβ of the cam 77 as shown in FIG.

Thus, a torque limiter function for interrupting a torque equal to or more than a predetermined value is obtained.

For example, if the torque limiter function is set to operate below the hump torque of the viscous fluid coupling disposed on the rear wheel side, a power transmission system on the rear wheel side such as a propeller shaft, a rear differential, and a rear axle can be provided. Is protected from excessive hump torque, and the durability is greatly improved.

In the four-wheel drive state, the cam thrust force F
Since α and the cam thrust force Fβ press and hold the clutch member 27 from the opposite direction, even if it receives vibration during traveling,
The play of the clutch member 27 is prevented, the engagement of the dog clutch 71 is prevented from being released against the driver's intention, and the vehicle can run in a stable four-wheel drive vehicle state.

The torque limiter function is provided when the meshing clutch 55 is connected and operated by a spring (shift spring 53) as in the 2-4 switching device 51 of the second embodiment, or the operating force is reduced. This is particularly preferable in the case of a power transmission device configured to connect and operate the dog clutch with an actuator having a small size.

The power transmission device of the present invention may be used in a front-wheel-side power transmission system of a rear-wheel drive-based four-wheel drive vehicle, different from the above embodiments.

In the power transmission device of the present invention, an actuator other than an electromagnet, for example, a hydraulic actuator may be used as an actuator constituting the moving operation means.

[0110]

According to the power transmission device of the first aspect, the driving force is intermittently driven by the meshing clutch having a small load per unit area of the meshing teeth. The driving force can be cut off smoothly with a small operation force.

Therefore, it is not necessary to increase the size of the moving operation means, and it is possible to prevent an increase in the size and weight of the power transmission device and a reduction in engine fuel efficiency.

Further, when there is a difference in the tire diameter between the front and rear wheels, when the vehicle turns sharply, or when the viscous fluid coupling is humped, the engagement of the dog clutch can be smoothly released when necessary, for example. It is possible to prevent a reduction in fuel consumption, a tight corner breaking phenomenon, a reduction in durability, and the like.

According to the second aspect of the present invention, the same effects as those of the first aspect are obtained, and the four-wheel drive state of the vehicle is provided by the operation force of the actuator. As a result, the actuator can be stopped, and the fuel efficiency is greatly improved.

According to the third aspect of the invention, the same effect as that of the first aspect is obtained.

The invention of claim 4 is the invention of claims 1 to 3
In addition to obtaining the same effect as any one of the above, the self-locking function of the meshing clutch is obtained by the cam provided at the connecting portion between the power transmission member and the clutch member, and the clutch member is in the meshing position even if it receives vibration during traveling Since the engagement is maintained, the engagement of the dog clutch is prevented from being released against the driver's intention, and the vehicle can run in a stable four-wheel drive state.

The invention of claim 5 is the first to third aspects of the present invention.
And the cam provided on the dog clutch provides a torque limiter function for interrupting a torque equal to or greater than a predetermined value.For example, the torque limiter function operates when the torque is equal to or less than the hump torque of the viscous fluid coupling. With this setting, a decrease in the durability of the power transmission system is prevented.

The invention of claim 6 is the invention of claims 2 to 5
In addition to obtaining the same effect as any one of the above, the actuator using the electromagnet has a simple configuration, can be configured at low cost, has high packaging properties, and is easy to incorporate.

Further, the power transmission device of the present invention, which can smoothly move the clutch member with a small operating force, is particularly advantageous in this configuration in which an electromagnet having a relatively small operating force is used for the actuator. is there.

Further, since the operating force is small, the power consumption of the electromagnet is small, and the load on the battery is light, so that the decrease in the engine fuel efficiency is reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment in a four-wheel drive state.

FIG. 2 is a cross-sectional view showing a meshing state of a meshing clutch used in the first embodiment.

FIG. 3 is a sectional view showing the first embodiment in a two-wheel drive state.

FIG. 4 is a cross-sectional view showing a state in which the engagement of the engagement clutch used in the first embodiment is released.

FIG. 5 is a sectional view showing a second embodiment in a four-wheel drive state.

FIG. 6 is a cross-sectional view showing a meshing state of a meshing clutch used in the second embodiment.

FIG. 7 is a sectional view showing a second embodiment in a two-wheel drive state.

FIG. 8 is a cross-sectional view showing a state in which the engagement of an engagement clutch used in the second embodiment has been released.

FIG. 9 is a cross-sectional view of the meshing clutch and the cam 69 used in the third embodiment, showing a state where the meshing of the meshing clutch is released.

FIG. 10 is a cross-sectional view of the dog clutch and cam 69 used in the third embodiment, showing a state in which the dog clutch has been engaged, the cam 69 has been activated, and the self-lock function has been activated.

FIG. 11 is a sectional view of a dog clutch and cams 69 and 77 used in the fourth embodiment.

FIG. 12 is a cross-sectional view of the dog clutch and cams 69 and 77 used in the fourth embodiment, showing a state in which the cam 77 has been operated and the torque limiter function has been operated.

FIG. 13 is a sectional view of a conventional example.

[Explanation of symbols]

1, 51 2-4 switching device (power transmission device) 23, 25 power transmission member 27 clutch member 29 meshing clutch operated by electromagnet 31 31 electromagnet (actuator) 33 return spring (biasing member) 37 39, meshing teeth (connecting portion of members 25, 27) 41, 43 meshing teeth of meshing clutch 29 53 shift spring (biasing member) 55 meshing clutches 57, 59 meshed by shift spring 53 meshing teeth 57, 59 meshing teeth (members 23, 27) 27, a meshing tooth of the meshing clutch 55 65, 67 a meshing tooth (a connecting portion of the members 23, 27) 69 a cam provided at a connecting portion of the members 23, 27 71 a meshing operation by the shift spring 53 Mesh clutch 73, 75 Mesh clutch Meshing teeth of latch 71 77 cam formed on meshing clutch 71

Claims (6)

[Claims] In a four-wheel drive vehicle, a pair of power transmission members arranged in a front wheel side power transmission system or a rear wheel side power transmission system, and a connecting portion movably move to one power transmission member. A clutch member connected thereto, a clutch provided between the clutch member and the other power transmission member, and moving operation means for moving and operating the clutch member to intermittently connect and disconnect the clutch. A power transmission device comprising a meshing clutch formed oppositely and having meshing teeth having an axial tooth height, wherein the moving operation means is a meshing clutch for intermittently driving force by moving the clutch member in the axial direction. 2. The invention according to claim 1, wherein the moving operation means urges the clutch member in a direction in which the dog clutch is disengaged, and a clutch member opposing the urging force of the urging member. A power transmission device comprising: an actuating device for moving the clutch to connect the meshing clutch. 3. The invention according to claim 1, wherein the moving operation means includes an urging member for moving the clutch member in a connecting direction of the dog clutch, and moving the clutch member against the urging force of the urging member. A power transmission device comprising: an actuator that is operated to release the engagement of the dog clutch. 4. The invention according to claim 1, wherein a meshing tooth of a connecting portion connecting one of the power transmitting members and the clutch member is operated by receiving a transmitting torque. And a clutch member is pressed toward the meshing position of the meshing clutch by the cam thrust force. 5. The invention according to claim 1, wherein each of the meshing teeth of the meshing clutch forms a cam that operates by receiving a transmission torque, and the transmission torque has a predetermined value. , The clutch member is retracted to the disengaged position of the mesh clutch by the cam thrust force. 6. The invention according to any one of claims 2 to 5, wherein the actuator comprises an armature and an electromagnet for attracting the armature, and the clutch member comprises the armature. A power transmission device comprising: