JPH0466731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a two-wheel/four-wheel drive switching device for an automobile.

(Prior art and its problems) A transfer clutch is interposed between one of the front and rear differentials, for example, between the front wheel differential and the engine, and the transfer clutch is moved to the free side of the transfer clutch. Two-wheel drive is achieved by switching the transfer clutch to the lock side, and four-wheel drive is achieved by switching the transfer clutch to the lock side.
In automobiles equipped with a wheel drive switching device, a freewheel clutch is interposed between the front wheels and the front wheel differential device that is disconnected from the engine during two-wheel drive. Conventionally, there has been known a system in which the differential gear and the front wheels are separated to reduce power loss.

By the way, when the transfer clutch is of the synchromesh type, the locking operation of the transfer clutch is performed as follows when switching from two-wheel drive to four-wheel drive while the vehicle is running. That is, as shown in FIG. 4a, the sleeve 1 on the clutch driving side is rotated by the engine.
to the right in the same figure, and remove the sleeves 1 and 2.
First, the sleeve 1 is engaged with the synchro ring 3 interposed between the spline wheel 2 on the driven side of the clutch which is stopped during wheel drive, and then the sleeve 1 is further inserted as shown in Fig. 4b while being integral with the synchro ring 3. By shifting as shown, the inner circumferential surface of the boss of the synchro ring 3 and the tapered outer circumferential surface of the boss of the clutch driven side spline wheel 2 are brought into frictional contact. After the clutch driven side spline wheel 2 is synchronized with the clutch driving side in this way, the sleeve 1 is moved further to the right than in FIG. 4b, and the sleeve 1 and the spline wheel 2 are brought into mesh with each other.

However, in the case of the above configuration, if the synchro ring 3 becomes stuck during the shift operation of the sleeve 1 due to seizure in the friction joint between the synchro ring 3 and the clutch driven side spline wheel 2, the synchro ring 3 and the clutch driven side For example, the positional relationship of the spline wheel 2 is
It is fixed in the state shown in Figure b, and the actuator thrust of the power shift alone is enough to release the synchronizer ring 3 and move the spline wheel 2.
The problem is that the wheels cannot be engaged with each other, making it impossible to switch to four-wheel drive.

(Purpose of the Invention) This invention was made to solve the above problem, and in a synchronized mesh type transfer clutch, the synchronized ring becomes stuck during the changeover from two-wheel drive to four-wheel drive. An object of the present invention is to provide a two-wheel/four-wheel drive switching device for an automobile that can effectively eliminate the stagnation and smoothly switch to four-wheel drive even in the case of a vehicle.

(Means for Achieving the Object) The present invention provides a synchromesh type transfer clutch between one of the front and rear wheel differentials and the engine, and A freewheel clutch is interposed between one differential device and the wheels connected to this differential device, and a displacement sensor detects the displacement of the transfer clutch toward the lock side, and based on the detection signal of this sensor, A two-wheel/four-wheel switching device for an automobile, which switches from two-wheel drive to four-wheel drive by moving a freewheel clutch toward the lock side,
In order to achieve the above object, the freewheel clutch is locked before the engagement/disengagement sleeve of the transfer clutch engages with the clutch driven gear, and the freewheel clutch is locked before the engagement/disengagement sleeve reaches the clutch driven gear engagement start position. The arrangement of the sensors is set so as to detect displacement of the connecting/disconnecting sleeve toward the lock side and output a detection signal. As a result, even if the synchronizer ring of the transfer clutch becomes stuck with the clutch driven gear during the changeover to four-wheel drive, the freewheel clutch can be switched to the lock side by the detection signal from the sensor. In this way, the synchronizer ring is unstacking due to the rotation difference between the rotation transmitted from the wheel side to the clutch driven side gear and the clutch driving side,
This allows for smooth switching to four-wheel drive.

(Embodiment) Fig. 1 shows an example of an automobile according to an embodiment of the present invention.
A schematic diagram of the entire wheel/four-wheel drive switching device is shown, and FIG. 2 is a longitudinal cross-sectional view of the transfer clutch and its surrounding mechanisms.

In FIG. 1, an engine 4 is connected to a rear wheel differential 7 via a transmission 5 and a rear wheel output shaft 6.
A front wheel drive gear 8 is rotatably provided on the rear wheel output shaft 6.

On the other hand, a front wheel output gear 9 having the same number of teeth as the front wheel drive gear 8 is provided on the front wheel output shaft 10, and this front wheel output gear 9 is connected to the front wheel drive gear 8 via a chain 11. There is. A spline wheel 12 as a clutch drive side gear and a spline wheel 13 as a clutch driven side gear are formed on the shaft portions of the rear wheel output shaft 6 and the front wheel drive gear 8, respectively, and between these spline wheels 12 and 13. A sleeve 14 that shifts and connects and disconnects them, and a spline wheel 1.
The spline wheel 1 is provided with a synchro ring 15 having an inner circumferential surface that can be frictionally bonded to the tapered outer circumferential surface of the boss 13a (shown in FIG. 2) of the spline wheel 1.
2, 13, the sleeve 14, and the synchronizer ring 15 constitute a transfer clutch 16. The transmission 5 has an input shaft 17 that receives power from the engine 4, and a transmission shaft 18 that is provided corresponding to the rear wheel output shaft 6. An input gear 19 is rotatably provided on the input shaft 17, and a first reduction gear 2 meshes with the input gear 19.
0 is fixed to the speed change shaft 18. Also, the gear shift shaft 1
A second reduction gear 21 is fixed to the front wheel drive gear 8, and an output gear 22 that meshes with the second reduction gear 21 is fixed to the shaft portion of the front wheel drive gear 8. The input shaft 17 is provided with a shift sleeve 23 that can be freely shifted in the axial direction, and spline wheels 24 and 25 are formed on the shafts of the input shaft 17 and the input gear 19, respectively. The input gear 19 and the input shaft 17 are connected, or the input shaft 17 and the rear wheel output shaft 6 are directly connected. Then, using the transmission 5, transfer clutch 16, etc., the power of the engine 4 is switched between high speed and low speed and transmitted only to the rear wheels 26, 26', or is transmitted to the rear wheels 26, 26' and the front wheels 27, 27'. A transmitting transfer 28 is configured. The power of the engine 4, which is transmitted to the front wheel output shaft 10 via the transfer 28, is transmitted to the front wheels 27, 27' via the front wheel differential 29.

On the other hand, a carburetor 30 is installed on the intake side of the engine 4.
A supercharger 31 is connected to the carburetor 30. This supercharger 31 has a turbine 32 driven by the exhaust energy of the engine 4.
and a compressor 33 that is directly connected to this turbine 32 and pressurizes intake air, and the compressor 33 and the carburetor 3
A surge tank 34 is interposed between the terminal and the terminal 0.

A diaphragm type transfer actuator 35 is connected to the sleeve 14 of the transfer clutch 16 described above. In the transfer actuator 35, one compartment 35a partitioned off by a diaphragm is communicated with a first on-off valve 36. This first on-off valve 36 has 3 ports 2
It consists of a solenoid valve in one position, and the solid line indicates the solenoid's OFF state, and the imaginary line indicates its ON state. A second port of the first on-off valve 36 is connected to the downstream side of the carburetor 30 via a check valve 37, and a third port is opened to the atmosphere via a filter 38. Further, the other branch chamber 35b of the transfer actuator 35 is communicated with a second on-off valve 39. This second on-off valve 39 is also composed of a 3-port, 2-position solenoid valve, and the state in which the solenoid is turned off is shown by a solid line, and the state in which the solenoid is turned on is shown by a phantom line. In this case as well, the second port is connected to the downstream side of the vaporizer 30,
The third port is open to the atmosphere. The solenoids of the first on-off valve 36 and the second on-off valve 39 are both connected to the 4WD switch of the power shift switch 40.
It is connected to a first power source 41 via a switching contact 40a.

On the other hand, a freewheel clutch 44 is provided between the shaft of the differential side gear 42 of the front wheel differential 29 and the front axle 43 to connect and disconnect them. A diaphragm freewheel actuator 45 is connected to the freewheel clutch 44. In this freewheel actuator 45, one compartment 45b partitioned off by a diaphragm is communicated with a third on-off valve 46. This third on-off valve 46 is also composed of a 3-port, 2-position solenoid valve, and the state in which the solenoid is turned off is shown by a solid line, and the state in which the solenoid is turned on is shown by a phantom line. The second port of the third on-off valve 46 is also connected to the downstream side of the carburetor 30 via a check valve 37, and the third port is opened to the atmosphere via a filter 38. Further, the other compartment 45a of the freewheel actuator 45 is communicated with the first on-off valve 36 described above.

In the vicinity of the transfer clutch 16 described above, there is a sleeve 1 of the transfer clutch 16.
4 is a spline wheel 12 on the rear wheel output shaft 6 side
and the spline wheel 13 on the front drive gear 8 side.
A position switch 47 is disposed which is turned on by detecting displacement to a shift position in which the four-wheel drive is engaged, that is, a shift position during four-wheel drive. As shown in FIG. 3, the position of the position switch 47 is determined from a time point A when the sleeve 14 starts to mesh with the synchro ring 15 to a time point when the sleeve 14 starts to mesh with the spline wheel 13 on the front wheel drive gear 8 side. Sleeve 14 in section T on the way to B
is detected and set to work.
The solenoid of the third on-off valve 46 described above is connected to a second power source 48 via the position switch 47.

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

As shown by the solid line in FIG. 1, when the power shift switch 40 is set to the 2WD switching contact 40b side, the first on-off valve 36, the second on-off valve 39
Both solenoids are off (state shown by solid lines). Therefore, transfer actuator 3
5 is open to the downstream side of the carburetor 30 and is connected to the sleeve 14 of the transfer clutch 16.
is placed at a shift position where the spline wheel 12 on the clutch driving side and the spline wheel 13 on the clutch driven side are separated, as shown by solid lines in the figure. Therefore, the power of engine 4 is
Transmission device 5, rear wheel output shaft 6, rear wheel differential device 7
The signal is transmitted to the rear wheels 26, 26' via the front wheel differential device 29, and is not transmitted to the front wheel differential 29 side. That is, rear wheel 2
6, 26' provides two-wheel drive. Incidentally, at this time, the shift sleeve 23 is set at the position shown by the solid line in FIG.

On the other hand, in this state, the position switch 47
is off because no displacement of the sleeve 14 toward the four-wheel drive side is detected, and the solenoid of the third on-off valve 46 is also off (state shown by the solid line).
Therefore, the branch chamber 45b of the freewheel actuator 45 is open to the atmosphere, while the first on-off valve 36 communicates with the downstream side of the carburetor 30 as described above, so one of the branch chambers 45a becomes under negative pressure. The freewheel clutch 44 is placed in a shift position where the differential side gear 42 of the front wheel differential 29 and the front axle 43 are separated from each other, as shown by the solid line in FIG.

Next, when the power shift switch 40 is switched and connected to the 4WD switching contact 40a side as shown by the virtual line in FIG. 1, the first on-off valve 36 and the second on-off valve 39 are connected.
Solenoids are both on (state shown by phantom lines)
Therefore, the branch chamber 3 of the transfer actuator 35
5a is switched to atmospheric pressure and the compartment 35b is switched to negative pressure, and the sleeve 1 of the transfer clutch 16 is switched to
4 is displaced to a shift position where it meshes with the spline wheel 12 on the clutch driving side and the spline wheel 13 on the clutch driven side as shown by the imaginary line in the figure. In this operation, the sleeve 14 first engages with the synchro ring 15 shown in FIG.
Due to the frictional bond between the inner circumferential surface of the boss portion of the synchronizer ring 15, which further shifts together with the sleeve 14, and the tapered outer circumferential surface of the boss 13a on the spline wheel 13 side, the synchronizer ring 15 is brought into a stopped state during two-wheel drive. The spline wheel 13 side rotates synchronously with the clutch drive side, and the sleeve 14 meshes with the spline wheel 13 under this synchronous state.

During this switching operation, position switch 4
7 detects the displacement of the sleeve 14 toward the four-wheel drive side and turns on, so the solenoid of the third on-off valve 46 is turned on (the state shown by the imaginary line in FIG. 1) (the solenoid of the first on-off valve 36 is turned on first by switching the power shift switch 40),
The branch chamber 45a of the freewheel actuator 45 is switched to atmospheric pressure, and the branch chamber 45b is switched to negative pressure,
The freewheel clutch 44 is displaced as shown in phantom lines in FIG. 1 to establish a connection between the differential side gear 42 of the front wheel differential 29 and the front wheels 43. Therefore, even if the synchronizer ring 15 is stuck at the frictional joint with the spline wheel 13, the rotation of the front wheels 27, 27' is caused by the front wheel differential 29, the front wheel output side 10, and the front wheel output gear 9. ,
The spline wheel 13 passes through the chain 11
Due to the rotation difference between this rotation and the synchro ring 15 on the clutch drive side, the synchro ring 15 is released from the stuck state.
The sleeve 14 is easily shifted and engages with the spline wheel 13, thereby switching to a four-wheel drive state.

In this four-wheel drive, when the gear shifting sleeve 23 is set at the position shown by the solid line in FIG. On the other hand, when the shift sleeve 23 is set at the position shown by the imaginary line in the figure, the power of the engine 4 is transmitted from the input shaft 17 to the input gear 19 and the first reduction gear 20. , the transmission shaft 18, the second reduction gear 21, and the output gear 22, the signal is transmitted to the rear wheel output shaft 6 and the front wheel drive gear 8, resulting in low-speed driving.

(Effects of the Invention) As described above, according to the vehicle two-wheel/four-wheel drive switching device of the present invention, the vehicle switches from two-wheel drive to four-wheel drive while driving.
When switching to wheel drive, even if a stagnation occurs between the synchro ring in the transfer clutch and the gear on the driven side of the clutch, the freewheel clutch, which was set in the free state during two-wheel drive, will shift to the locked side during the above switching. To switch,
The rotation of the wheels is transmitted to the clutch driven side gear, and the synchro ring is unstayed due to the difference in rotation between the rotation and the clutch drive side gear, thereby smoothly switching to four-wheel drive without becoming unable to switch. This has the effect of being able to.

[Brief explanation of drawings]

Fig. 1 shows two parts of an automobile which is an embodiment of this invention.
A schematic diagram of the entire wheel/four-wheel drive switching device, FIG. 2 is a longitudinal sectional view showing the transfer portion, FIG. 3 is an explanatory diagram of setting the detection operating point of the position switch, and FIG. 4 a, b is an explanatory diagram showing the operation of a transfer clutch in a conventional example. 4...Engine, 7...Rear wheel differential, 12
... Spline wheel, 13 ... Spline wheel, 14 ... Sleeve, 15 ... Synchro ring, 16 ... Transfer clutch, 29 ...
Front wheel differential, 44...freewheel clutch, 47...position switch.

Claims (1)

[Scope of Claims] 1. A synchromesh type transfer clutch is interposed between one of the differential devices for the front and rear wheels and the engine, and one of the differential devices and the engine; A freewheel clutch is interposed between the wheels connected to this differential device, a sensor detects the displacement of the transfer clutch toward the lock side, and the freewheel clutch is moved to the lock side based on the detection signal of this sensor. Run it to 2
In a two-wheel/four-wheel drive switching device for an automobile that switches from wheel drive to four-wheel drive, the freewheel clutch is to be locked before the connecting/disconnecting sleeve of the transfer clutch engages with the driven gear of the clutch. An automobile characterized in that the sensor is arranged so as to detect displacement of the engagement/disconnection sleeve toward the locking side and output a detection signal before the engagement/disconnection sleeve reaches the clutch driven side gear engagement start position. 2-wheel/4-wheel drive switching device.