JPH032096B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) This invention enables switching to four-wheel drive in cold regions before the actuator for switching between two-wheel drive and four-wheel drive becomes frozen. The present invention relates to a two-wheel/four-wheel drive switching device for an automobile.

(Prior Art) For example, in a car that is equipped with four-wheel drive in order to ensure stable driving on snowy roads, conventionally, among the front and rear wheel differentials driven by the engine, for example, the front wheel Some engines have a transfer clutch interposed between the differential gear and the engine. In this case, if the transfer clutch is disengaged, only the rear wheels will be driven, and if the transfer clutch is engaged, both the front and rear wheels will be driven (for example,
(Japanese Patent Application Laid-Open No. 114132/1983).

(Problem to be solved by the invention) By the way, if the engine is stopped for a long time when the outside temperature is low, such as in a cold region, the temperature inside the engine room will drop accordingly. An actuator installed in the engine room that connects and disconnects the transfer clutch may freeze, making it impossible to operate the actuator.

In the above case, if the switching between 2-wheel and 4-wheel drive is in the 2-wheel drive state, that is, when the transfer clutch is disengaged, the transfer clutch will be engaged even if the next attempt is made to switch to 4-wheel drive. I will not be able to do it. For this reason, although four-wheel drive is more preferable for driving than two-wheel drive when the road surface is snowy or frozen, there is an inconvenience that the vehicle cannot be driven using four-wheel drive.

(Purpose of the Invention) This invention was made with attention to the above-mentioned circumstances, and even when the actuator that connects and disconnects the transfer clutch freezes due to a drop in outside temperature in a cold region, the The purpose is to ensure wheel drive driving.

(Structure of the Invention) A feature of the present invention for achieving the above object is that in a two-wheel/four-wheel drive switching device for an automobile equipped with a transfer clutch, the transfer clutch is activated in conjunction with engine drive stop. The point is that an interlocking means for connecting and operating is provided.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1 is a car, and this car 1 has a drive device 2,
It has a front wheel device 3 and a rear wheel device 4 driven by this drive device 2.

The drive device 2 has an engine 6, a carburetor 7 is connected to the intake side of the engine 6, and a supercharger 8 is connected to the carburetor 7. This supercharger 8 has a turbine 9 driven by the exhaust energy of the engine 6, and a compressor 10 that is directly connected to the turbine 9 and pressurizes intake air. A surge tank 11 is interposed between them.

To explain the front wheel device 3, 13,1
3' is a front wheel, and a pair of left and right front axles 14, 14' are connected to each of the front wheels 13, 13', respectively.
Further, a front wheel differential device 15 is provided between the front axles 14, 14'. This front wheel differential device 1
Reference numeral 5 is of a known type and includes a drive pinion 16 on the input side and a pair of left and right differential side gears 17, 17' on the output side.

To explain the rear wheel device 4, like the front wheel device 3, the rear wheel device 4 is composed of a pair of left and right rear wheels 19, 19', a rear axle 20, 20', and a rear wheel differential device 21, This rear wheel differential device 21
has a drive pinion 22.

The engine 6 and front and rear wheel differentials 15 and 2
1 through a transfer 24. This transfer 24 switches the power of the engine 6 between high speed and low speed and transmits it only to the rear wheels 19, 19', or in addition to this, the power is transmitted to the front wheels 13, 13'.
Also communicate.

The transfer 24 will be explained in more detail.

This transfer 24 includes an input shaft 25 that receives power from the engine 6, a front wheel output shaft 27 connected to a drive pinion 16 of a front wheel differential 15 via a front wheel propulsion shaft 26, and a rear wheel propulsion shaft. Drive pinion 2 of rear wheel differential 21 via 28
2 and a rear wheel output shaft 29 provided coaxially with the input shaft 25.

Further, the transfer shaft 24 has a transmission 31 . This transmission 31 is connected to the input shaft 25
and a transmission shaft 32 provided corresponding to the rear wheel output shaft 29. An input gear 33 is freely rotatably provided on the input shaft 25, and a first reduction gear 34 is supported on the speed change shaft 32 so as to mesh with the input gear 33. Further, a second reduction gear 35 is supported by the speed change shaft 32, and an output gear 36 is freely rotatably provided on the rear wheel output shaft 29 so as to mesh with the second reduction gear 35.

An engager 38 is provided on the input shaft 25 so as to be slidable in the axial direction. The engaging element 38 directly connects the input shaft 25 and the rear wheel output shaft 29 or connects the input shaft 25 and the input gear 33 by moving in the axial direction. 39 is a chain transmission means, and this chain transmission means 39 connects the output gear 36 and the output shaft 2 for the front wheels.
7 are connected.

Further, the output gear 36 is connected to the rear wheel output shaft 29.
A transfer clutch 40, which is a known synchromesh type clutch, is provided to connect and disconnect power transmission to the motor.

Then, as shown by the solid line in the figure, the above-mentioned engager 38
When the input shaft 25 and the rear wheel output shaft 29 are connected by operating the transfer clutch 40 and the rear wheel output shaft 29 and the output gear 36 are disconnected by operating the transfer clutch 40, the power of the engine 6 is transferred at high speed. Rear wheel differential device 2
1 to only the rear wheels 19, 19'. That is, this is a high-speed two-wheel drive state.

Connect the input shaft 25 and the rear wheel output shaft 29 by operating the engaging element 38 (shown by a solid line in the figure), and
When the transfer clutch 40 is operated to connect the rear wheel output shaft 29 and the output gear 36 (shown by a chain double-dashed line in the figure), the power of the engine 6 is transferred at high speed to the rear wheel via the rear wheel differential 21. The power from the engine 6 is transmitted to the front wheels 13, 13' via the front wheel differential 15. That is, this is a high-speed four-wheel drive state.

In addition, as shown by the two-dot chain line in the figure, the same engager 3
8 to connect the input shaft 25 and the input gear 33, and operate the transfer clutch 40 to connect the rear wheel output shaft 29 and the output gear 36, first, the power of the input shaft 25 is Each gear 33-36
The decelerated power is transmitted to the front and rear wheels 13 and 19 via the front and rear wheel differentials 15 and 21. That is, this is a low-speed four-wheel drive state.

A diaphragm type transfer actuator 42 is provided for connecting and disconnecting the transfer clutch 40. One chamber 42a partitioned off by a diaphragm in the transfer actuator 42 is communicated with the atmosphere via a first on-off valve 43. The first on-off valve 43 is a 3-port, 2-position solenoid valve, and a solid line indicates a state in which the solenoid is OFF, and a chain double-dashed line indicates a state in which the solenoid is ON. In this first on-off valve 43, one of the chambers 4
The third port other than the port connected to 2a and the atmospheric side, respectively, is connected to the negative pressure tank 45 and the check valve 4.
4, it is connected to the downstream side of the carburetor 7, that is, to the part of the engine 6 where the intake negative pressure is high.

Further, the other chamber 42b of the transfer actuator 42 is communicated with the atmosphere via a second on-off valve 46. This second on-off valve 46 has the same configuration as the first on-off valve 43, and its third port is connected to the downstream side of the carburetor 7.

The first on-off valve 43 is normally on, and one chamber 42a of the transfer actuator 42 is communicated with the downstream side of the carburetor 7 by this first on-off valve 43, and is made to have a negative pressure. Ru. Further, the second on-off valve 46 is turned off, and the other chamber 42b of the transfer actuator 42 is opened in the second opening/closing valve 46.
It is communicated with the atmosphere side by an on-off valve 46, and the differential pressure between them causes the transfer actuator 42 to
is activated. In conjunction with the transfer actuator 4, the transfer clutch 40 cuts off the power transmission from the rear wheel output shaft 29 to the output gear 36 (shown by a solid line in the figure). In this way, the two-wheel drive state described above can be obtained.

Moreover, if the first on-off valve 43 is turned off and the second on-off valve 46 is turned on, contrary to the above, one chamber 42 of the transfer actuator 42
The chamber a is connected to the atmosphere, and the other chamber 42b is connected to the downstream side of the carburetor 7 and has a negative pressure, and the transfer actuator 42 is operated by the differential pressure between them. A transfer clutch 40 is operated in conjunction with this transfer actuator 42.
connects the rear wheel output shaft 29 and the output gear 36 (indicated by a two-dot chain line in the figure). In this way, the four-wheel drive state described above can be obtained.

Further, in the above configuration, in order to reduce power loss during two-wheel drive, a freewheel clutch 47 is provided between the front axle 14 and the differential side gear 17.
is mediated. The freewheel clutch 47 is a known dog type clutch that connects and disconnects power transmission from the differential side gear 17 to the front wheels 14. When the freewheel clutch 47 is disconnected during two-wheel drive, the front wheel differential 15 will idle even if the front wheels 13, 13' are rotating due to driving, so the drive pinion 16 and front wheel propulsion shaft 26 will be rotated. Unnecessary rotation is prevented.

A diaphragm freewheel actuator 48 is also provided for operating the freewheel clutch 47. In the freewheel actuator 48, one chamber 48a partitioned off by a diaphragm is connected to the atmosphere via the first on-off valve 43. Further, the other chamber 48b of the freewheel actuator 48 is also connected to the atmosphere via a third on-off valve 50. The third on-off valve 50 is a 3-port, 2-position solenoid valve having the same configuration as the first on-off valve 43. In this third on-off valve 50, a third port other than the ports connected to the other chamber 48b and the atmosphere side is connected to the downstream side of the carburetor 7.

The first on-off valve 43 is normally on, and one chamber 48a of the freewheel actuator 48 is communicated with the downstream side of the carburetor 7 by this first on-off valve 43, and is made to have a negative pressure. Ru. Further, the third on-off valve 50 is turned off, and the other chamber 48b of the freewheel actuator 48 is opened in the third opening/closing valve 50.
The on-off valve 50 communicates with the atmosphere, and the differential pressure between them causes the freewheel actuator 48 to
is activated. In conjunction with this freewheel actuator 48, the freewheel clutch 47 disconnects the front axle 14 and the differential side gear 17 (shown by solid lines in the figure).

Also, contrary to the above, if the first on-off valve 43 is turned off and the third on-off valve 50 is turned on, one chamber 48a of the freewheel actuator 48 is communicated with the atmosphere, and the other chamber 48b is connected to the atmosphere. The freewheel actuator 48 is connected to the downstream side of the vessel 7 and has a negative pressure, and the differential pressure between them causes the freewheel actuator 48 to operate.
In conjunction with this freewheel actuator 48, the freewheel clutch 47 operates on the front axle 14.
and the differential side gear 17 (shown by a chain double-dashed line in the figure).

Next, an electrical device for switching between the two-wheel drive state and the four-wheel drive state will be explained.

52 is a first power source, and a changeover switch 53 is connected to this first power source 52. This changeover switch 53
is a switch for selecting 2-wheel drive or 4-wheel drive; 2-wheel drive contact 53a and 4-wheel drive contact 5
3b. A first on-off valve 43 is connected to the two-wheel drive contact 53a.

On the other hand, the transfer clutch 40 connects the rear wheel output shaft 29 and the output gear 36, and connects the rear wheel output shaft 29 and the output gear 36.
When driving front wheels 13, 13' in addition to wheel 9',
A limit switch 55 is provided as a detection means for detecting the operation of the transfer latch 40. The third on-off valve 50 is connected to a second power source 56 via this limit switch 55.

In addition, a second on-off valve 4 is provided at the four-wheel drive contact 53b.
6 is connected.

Next, the operation when switching between two-wheel drive and four-wheel drive using the above configuration will be explained.

The above changeover switch 53 is connected to the two-wheel drive contact 53a.
When switched to , the first on-off valve 43 is turned on and the second on-off valve 46 is turned off. Therefore, the transfer actuator 42 is actuated by the negative pressure downstream of the carburetor 7, and the rear wheel output shaft 29 and the output gear 36 are disconnected. As a result, the power of the engine 6 is transmitted only to the rear wheels 19, 19'.
Two-wheel drive is provided (indicated by solid lines in the figure).

In the above case, since the limit switch 55 is turned off, the third on-off valve 50 is also turned off. Therefore, the freewheel actuator 48 is actuated by the negative pressure downstream of the carburetor 7, and the front axle 14 and the differential side gear 17 are disconnected.

Next, the changeover switch 53 is switched from the two-wheel drive state.
When switching to the four-wheel drive contact 53b, first,
The first on-off valve 43 is turned off, while the second on-off valve 4
6 is turned on. Then, the transfer actuator 42 is activated and the transfer clutch 4 is activated.
0 connects the rear wheel output shaft 29 and the output gear 36. At this time, since the transfer clutch 40 is in the connected state, the limit switch 55 is
is turned on, thereby turning on the third on-off valve 50, and the freewheel actuator 48 turns on the carburetor 7.
Actuated by downstream negative pressure, freewheel clutch 47 connects front axle 14 and differential side gear 17.

In the above configuration, an interlocking means 57 is provided for connecting the transfer clutch 40 when the engine 6 is stopped.

This interlocking means 57 will be explained below.

Reference numeral 58 denotes an ignition contact, and this ignition contact 58 is turned on and off as follows in conjunction with an ignition switch (not shown). That is, while the engine 6 is driving, the ignition contact 58 is turned on (as shown by the solid line in the figure), and when the engine 6 stops driving, the ignition contact 58 is turned off. (Indicated by a chain double-dashed line in the figure).

The interlocking means 57 also includes a normally open A contact 59 that is turned on when the ignition contact 58 is turned off, and a normally closed B contact 60 that is turned off when the ignition contact 58 is turned off.
and is provided.

Then, the first on-off valve 43 and the two-wheel drive contact 53
The B contact 60 is interposed between the second on-off valve 46 and the two-wheel drive contact 53a, and the A contact 59 is interposed between the second on-off valve 46 and the two-wheel drive contact 53a.

When the drive of the engine 6 is stopped in the two-wheel drive state described above, that is, when the two-wheel drive contact 53a is turned on, the ignition contact 58 is turned off, and the ignition contact 58 is turned off. , the B contact 60 is turned off, and at the same time the A contact 59 is turned off.
is turned on.

Therefore, the first on-off valve 43 is turned off, the second on-off valve 46 is turned on, and the transfer actuator 42 is actuated thereby to open the transfer clutch 40.
is connected and operated. Also, the connection operation of the transfer clutch 40 causes the limit switch 55 to be activated.
is turned on, thereby turning on the third on-off valve 50, and following the connecting operation of the transfer clutch 40, the freewheel actuator 48 is operated to connect the freewheel clutch 47,
This results in a four-wheel drive state.

In the above embodiment, the freewheel clutch 47 is interposed between the front axle 14 and the differential side gear 17, but the freewheel clutch 47 may not be provided.

(Effects of the Invention) According to the present invention, in a two-wheel/four-wheel drive switching device for an automobile provided with a transfer clutch,
Since an interlocking means is provided to connect and operate the transfer clutch in conjunction with engine drive stoppage, 2
Switching from wheel drive to four-wheel drive is automatically performed in conjunction with engine drive stop. Therefore, even if the actuator that operates the transfer clutch intermittently is about to freeze due to a drop in the outside temperature in a cold region, the transfer clutch will have already been connected before freezing. Even if the actuator or the like freezes, traveling with four-wheel drive can be ensured.

[Brief explanation of the drawing]

The figure is an overall view showing an embodiment of the invention. 1...Car, 6...Engine, 13,13'
...Front wheel, 15... Front wheel differential device, 19,1
9'... Rear wheel, 21... Rear wheel differential, 40...
...transfer clutch, 57...interlocking means.

Claims (1)

[Claims] 1 A vehicle in which a transfer clutch is interposed between one of the differential devices for the rear wheels before being driven by the engine and this engine.
A two-wheel/four-wheel drive switching device for an automobile, characterized in that the device is provided with interlocking means for connecting and operating a transfer clutch in conjunction with the stoppage of the engine.