JPH0238407B2 - 4RINKUDOSHANOKIRIKAEKIKO - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a 4-wheel drive vehicle that performs two-wheel drive using one of the front and rear wheels and four-wheel drive using both. The present invention relates to a switching mechanism that performs switching and switching to an emergent low (hereinafter referred to as EL) gear, which has a higher gear ratio than the first gear incorporated in the transmission.

[Conventional technology]

Such a four-wheel drive vehicle can transmit engine output to the road surface more efficiently than a two-wheel drive vehicle. Therefore, when driving with 4-wheel drive on steep climbs or rough roads, we have taken into account the fact that a larger gear ratio in the transmission can more effectively demonstrate the performance of 4-wheel drive. For example, 4 forward speeds and 1 reverse speed
In addition to transmission mechanisms such as gears, there are also systems that incorporate a mechanism for obtaining a gear ratio with a higher gear ratio than the first gear.

As a mechanism for obtaining a gear ratio having a larger gear ratio than the first speed, for example, the present applicant has already proposed a mechanism in Japanese Patent Application No. 55-154415 (Japanese Unexamined Patent Publication No. 57
-Using an auxiliary transmission (see Publication No. 77230),
Or it consists of a pair of gear mechanisms.

[Problem to be solved by the invention]

Here, the EL gear stage, which has a higher gear ratio than the first gear obtained by the auxiliary transmission or a pair of gear mechanisms, is provided for four-wheel drive, and is not necessary for two-wheel drive; When used with wheel drive, an excessive load is placed on the drive wheel differential, axle, etc.
Therefore, if these are not made to have greater strength than necessary, there is a risk of damaging the drive yarn.

Therefore, in general, the EL gear stage is structured so that it can only be used when driving 4-wheel drive, and for this purpose, an auxiliary transmission is used, and when switching between 2-wheel drive and 4-wheel drive, the auxiliary transmission The applicant has already proposed a mechanism in which the switch is switched only during four-wheel drive, but these mechanisms are based on a mechanical link mechanism.

By the way, it is common practice to perform various operations using the engine's suction pipe negative pressure.
In the case of wheel drive vehicles as well, there is a prior art technique in which switching between two and four wheel drive is performed using suction pipe negative pressure, as seen in Japanese Utility Model Publication No. 8821/1983, for example. However, this does not address the relationship with the EL gear stage, which is the problem of the present invention.

In view of these circumstances, the present invention has been developed to
It incorporates a pair of gear mechanisms that obtain the EL gear stage, and organically combines its operating system, the operating system for the 2/4-wheel drive switching device, and the driver's manual 2/4-wheel drive switching operating system. It is possible to switch between 2-wheel drive or 4-wheel drive by manual operation by the driver, but if the vehicle is in 2-wheel drive when shifting to EL gear, it is necessary to switch to 4-wheel drive.
The purpose of the present invention is to provide a switching mechanism for a 4-wheel drive vehicle that makes it impossible to switch from 4-wheel drive to 2-wheel drive in the EL gear, so that the EL gear can only be obtained with 4-wheel drive. shall be.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an output side of a transmission having a pair of gear mechanisms for obtaining an emergent low gear position with a gear ratio larger than the first speed of the transmission. In a four-wheel drive vehicle configured to transmit power to the other of the front and rear wheels via a transfer device that is connected to a final reduction gear and switches between two and four-wheel drive, a two- and four-wheel-drive switching selector valve; A switching valve that is linked to a shifter rail that shifts to the Emergencies Low gear,
The above-mentioned switching system has an actuator attached to a transfer device that performs a switching operation between two and four-wheel drive, and links the negative pressure inlet port that receives intake pipe negative pressure and the atmospheric pressure inlet port with the outlet port by moving the spool. A selector valve communicates with the control chamber on the opposite side of the shifter rail of the switching valve which communicates the negative pressure inlet port and two drain ports with each of the two negative pressure outlet ports by movement of the spool, and the switching valve communicates with the control chamber on the opposite side of the shifter rail. The two negative pressure outlet ports of the valve are communicated with the two airtight chambers of the actuator separated by a diaphragm, and by switching the spool of the selector valve to 2-wheel drive or 4-wheel drive, the air is released. The inlet port or the negative pressure inlet port is selectively communicated with the control chamber of the switching valve via the outlet port, and the one of the switching valves is connected to the control chamber of the switching valve via the negative pressure inlet port and the negative pressure outlet port. It selectively communicates with the airtight chamber, one of the two drain ports is selectively communicated with the other airtight chamber via the negative pressure outlet port, and the switching selector valve switches between 2 and 4 wheel drive. When
The shifter rail is configured to restrict shifting to the emergent low gear so that the emergency low gear can only be obtained with four-wheel drive.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, to explain the transmission system of a four-wheel drive vehicle to which the present invention is applied in FIG. It is sequentially connected via a device 4 to an output shaft 5 which also transmits power to the other of the front and rear wheels during four-wheel drive.

The transmission 2 has a main shaft 6 to which engine power from the clutch 1 is input, and a counter shaft 7 arranged parallel to the main shaft 6. drive gear 8
a, 9a, 10a, and 11a are integrally formed, and there are driven gears 8b, 9b, 10b, and 11b on the subshaft 7 that constantly mesh with each of these gears and rotate idly.
Further, between each of the gears 8b and 9b, 10b and 11b, there are provided synchronizing mechanisms 12 and 13 for selectively integrating one of them with the subshaft 7 to take out a predetermined gear position.

Further, on the side of the above-mentioned transmission mechanism, a drive gear 14a for reverse speed is further connected to the main shaft 6 from the clutch 1 side.
A drive gear 15a of the EL gear stage is integrally formed, a driven gear 15b meshing with the drive gear 15a is formed on the subshaft 7, and a synchronization mechanism 16 that integrates the gear 15b with the subshaft 7 to take out the EL gear stage.

In the synchronizing mechanism 16, a driven gear 14b for reverse speed is formed on a sleeve 16a that engages with a shifter oak of a shift operation mechanism, which will be described later.By moving the sleeve 16a to the opposite side of the gear 15b, the gear 14b , is meshed with the gear 14a through the idler gear 14c, and rotates in reverse relative to the gear 14a to obtain reverse speed.

Here, the gear ratio of the gears 15a and 15b of the EL gear stage is set larger than the gear ratio of the first gear gears 8a and 8b, and this EL gear stage is set in the same select direction as the reverse speed. installed on the opposite side.

The final reduction gear 3 has a final reduction gear 18 that meshes with the output gear 17 on the subshaft 7 of the transmission 2 to decelerate and extract the shifted power, and a differential gear 19 is attached to this gear 18. The differential device 19 directly drives, for example, the rear wheels via an axle shaft 20.

The transfer device 4 includes a transfer gear 22 that meshes with the final reduction gear 18 of the final reduction device 3 and idles on a transfer shaft 21 that is rotatably supported, and the gear 22 is attached to the transfer shaft 21.
A dock clutch type switching device 23 is provided which is integrated into the main body. Further, the transfer shaft 21 is connected to the output shaft 5 via a pair of bevel gears 24a and 24b,
For example, power is also transmitted to the front wheels.

Next, the shift operation mechanism of the synchronization mechanisms 12 and 13 of the transmission 2 will be omitted, and the operation mechanism of the synchronization mechanism 16 will be explained in FIGS. 2 and 3. A shifter oak 26 that engages with the sleeve 16a of the synchronization mechanism 16 is attached, and by moving the shifter rail 25 to the left or right in the axial direction by operating a change lever, the EL gear stage or reverse speed can be selectively obtained. It's summery.

The right end side of this shifter rail 25, that is,
A switching valve 27 is provided on the side that obtains the EL gear stage.

The switching valve 27 includes a spool 28 that is provided so that the end faces of the shifter rail 25 can come into contact with each other.
A control chamber 29 formed on the opposite side of the spool 28 from the shifter rail 25, a spring 30 located in the control chamber 29 that biases the spool 28 toward the shifter rail 25, and a negative pressure inlet port 31a.
Two negative pressure outlet ports 31 provided for
b, 31c and drain ports 32a, 32b.

Then, the shifter rail 25 is shifted to the neutral position or the left reverse speed as shown in FIG. port 31
a communicates with port 31b, port 31c communicates with drain port 32b, and shifter rail 25 communicates with port 31b on the right side.
When the spool 28 moves to the right against the spring 30 due to a shift to the EL gear stage or when the control chamber 29 becomes negative pressure, the port 31a changes to the port 3.
1c, the port 31b is switched to communicate with the drain port 32a.

That is, the above port switching operation is performed when the shifter rail 25 is shifted to the EL gear stage by operating the change lever, and when the spool 28 is shifted to the right by negative pressure in the control chamber 29 other than that. It's becoming like that.

4 and 5, the operation mechanism of the switching device 23 of the transfer device 4 will be explained. In the switching device 23, the sleeve 23b of the hub 23a spline-fitted to the transfer shaft 21 has a sleeve 23b parallel to the shaft 21. 4WD-2WD placed in
shifter oak 34 at one end of shifter rail 33
A diaphragm actuator 35 is attached to the other end of the shifter rail 33.

The actuator 35 has two airtight chambers 37a and 37b partitioned by a diaphragm 36, and the diaphragm 36 has a shifter rail 3.
By selectively supplying negative pressure to the chamber 37a or 37b, the shifter rail 33 is moved to the left and right in the axial direction, and the sleeve 23b of the switching device 23 is connected to the transfer shaft. The sleeve 23b is engaged with the spline 22a of the gear 22 to provide four-wheel drive, or the sleeve 23b and the spline 22a are disengaged to switch to two-wheel drive.

Furthermore, as shown in FIG. 6, a knob 38 for manual switching between 2-wheel drive and 4-wheel drive provided in the driver's seat is connected to a switch selector valve 40 via a wire 39. 39
spool 41 with which it is tied, return spring 4
2, and negative pressure and atmospheric pressure inlet ports 43a, 4
3b and an outlet port 43c.

When the knob 38 is in the two-wheel drive position shown, the atmospheric inlet port 43b is connected to the outlet port 43b.
When the knob 38 is pulled and held in the four-wheel drive position, the spool 41 moves to the right to close the atmospheric inlet port 43b, open the negative pressure inlet port 43a, and communicate it to the outlet port 43c. Switching operation is performed.

The above-mentioned switching valve 27, actuator 35, and selector valve 40 are communicated through a passage as described below.

That is, the negative pressure passage 44 of the suction pipe negative pressure from the engine side is communicated with the port 31a of the switching valve 27 and the port 43a of the switching selector valve 40,
The ports 31b and 31c of the switching valve 27 are the passage 4.
5 and 46, the chamber 37b of the actuator 35,
37a, port 43 of the switching selector valve 40
c is connected to the control chamber 2 of the switching valve 27 by the passage 47.
9 are connected to each other.

Since the present invention is constructed in this manner, when the knob 38 is placed in the two-wheel drive position shown by the solid line in FIG.
Atmospheric pressure is supplied to the control room 29 of No. 7. Therefore, unless the shifter rail 25 is shifted to the EL gear stage, the spool 28 of the switching valve 27 is moved to the left by the spring 30 so as to come into contact with the end surface of the shifter rail 25 as shown in FIG.
through the passage 45 to the chamber 37 of the actuator 35
b to introduce negative pressure into the chamber 37b,
7a drains through the passage 46 and drain port 32b. Therefore, the chamber 37 of the actuator 35
The shifter rail 33 moves to the left side as shown in FIG. 6 due to the negative pressure of the switching device 2.
3 is a transfer gear 22 and a transfer shaft 2
1 and enters a two-wheel drive state.

Thus, in the transmission 2, the synchronizing mechanism 12,1
3 and the synchronizing mechanism 16 to shift the gears to 4 forward speeds and 1 reverse speed, the power is transferred from the output gear 17 of the subshaft 7 to the final reduction gear 1 of the final reduction device 3.
8. The power is transmitted only to the rear wheels via the differential device 19 and the axle shaft 20, and two-wheel drive driving is performed using only the rear wheels.

On the other hand, in the case of such two-wheel drive driving, when the shifter rail 25 is shifted to the EL gear by moving the synchronizing mechanism 16 to the right side by operating the change lever and shifting to the EL gear position by meshing the gears 15a and 15b, the shifter rail 25 , the spool 28 of the switching valve 27 moves to the right against the spring 30, and the negative pressure in the negative pressure passage 44 is thereby transferred to the passage 4.
6 to the other chamber 37a of the actuator 35.
It will be introduced in As a result, the shifter rail 33 moves to the right, and the transfer gear 22 is integrally connected to the transfer shaft 21 by the switching device 23, resulting in a four-wheel drive state. The power of the gear is transmitted to the rear wheels by the final reduction gear 3,
Also, from the transfer shaft 21 to the bevel gears 24a, 24
(b) It is also transmitted to the front wheels via the output shaft 5, thus automatically switching to four-wheel drive driving.

Also, pull the knob 38 as shown in FIG.
When the wheel drive position is set, the spool 41 in the switching selector valve 40 is also moved to the right by the wire 39, so that the negative pressure in the negative pressure passage 44 is supplied to the control chamber 29 of the switching valve 27 by the switching selector valve 40. , the spool 28 is moved to the right against the spring 30, similarly to the case of shifting the shifter rail 25 to the EL gear stage described above, and the switching device 2 by the actuator 35 is moved to the right side against the spring 30.
Step 3 puts the vehicle into four-wheel drive mode. Therefore, the power shifted to 4 forward speeds and 1 reverse speed of transmission 2, and
The power shifted to the EL gear is also transferred to the switching valve 27.
Since the switching operation has already been performed, the transmission is transmitted to the front and rear wheels, and four-wheel drive driving is performed.

Note that even if the knob 38 is returned to the 2-wheel drive position and the control chamber 29 is opened to the atmosphere during 4-wheel drive in the EL gear, the shifter rail 25 is still locked in the EL gear, so the spring 30 will not release. The restoring force does not work, and the switching valve 27 does not change to 2-wheel drive, but remains in 4-wheel drive. As a result, the switching valve 27 is moved to the left by the spring 30, resulting in two-wheel drive.

Thus, the shift pattern of the change lever according to the present invention is as shown in FIG.

The present invention is not limited to the above-mentioned embodiment, and may be implemented using a solenoid without using the wire 39.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when the switching selector valve is switched to 2-wheel drive or 4-wheel drive, the switching valve moves to the corresponding position, so that the intake pipe negative pressure is reduced to the switching valve. It is selectively introduced into one of the actuator's two airtight chambers through the 2-wheel drive mode, enabling 2- and 4-wheel drive states, and the EL gear stage, which has a higher gear ratio than 1st gear, can be used only in 4-wheel drive mode. Because of this, the performance of the 4-wheel drive vehicle is fully demonstrated, and the 2
In wheel drive, this gear cannot be used, and therefore there is no problem of excessive load being applied to the drive theory, differential, axle, etc. due to incorrect use of the gear in two-wheel drive. This effect can be expected with a simple mechanism that uses negative pressure in the intake pipe without using a link mechanism.
In addition, the operation of switching between 2-wheel drive and 4-wheel drive is performed by operating the switching selector valve and the shifter rail that communicates the switching valve to two positions.
It is very easy to operate and there is no risk of erroneous operation.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a transmission system as an embodiment of the switching mechanism according to the present invention, and Fig. 2 is a -
A cross-sectional view, Figure 3 is a - cross-sectional view of Figure 2, Figure 4.
The figure is a - cross-sectional view of Figure 1, and Figure 5 is a cross-sectional view of Figure 4.
-V sectional view, FIG. 6 is a piping diagram of the operating system, FIG. 7 is a piping diagram showing the operating state, and FIG. 8 is a diagram showing the shift pattern of the change lever according to the present invention. 2...Transmission, 3...Final reduction gear, 4...Transfer device, 5...Output shaft, 15a, 15b...
...EL gear stage gear, 23...Switching device, 25...
...Shifter rail, 27...Switching valve, 29...
Control room, 31a... Negative pressure inlet port, 31b, 3
1c...Negative pressure outlet port, 32a, 32b...Drain port, 35...Diaphragm actuator, 37a, 37b...Airtight chamber, 38...2.
4-wheel drive manual switching knob, 40...Switching selector valve, 43a...Negative pressure inlet port, 43b...
Atmospheric pressure inlet port, 43c... Outlet port, 44
...Negative pressure passage, 45 to 47...Passage.

Claims (1)

[Scope of Claims] 1. The output side of a transmission having a pair of gear mechanisms that obtains an emergent low gear with a gear ratio larger than the first speed of the transmission is connected to a final reduction gear for one of the front and rear wheels. In a 4-wheel drive vehicle in which power is transmitted to the other of the front and rear wheels via a transfer device that switches between 2- and 4-wheel drive, the 2- and 4-wheel-drive switching selector valve and the emergency low It has a switching valve that is linked to the shifter rail that shifts to the gear, and an actuator that is attached to the transfer device that switches between 2 and 4 wheel drive.It has a negative pressure inlet port that takes in intake pipe negative pressure and an atmospheric pressure inlet. The switching selector valve communicates the port with the outlet port by moving the spool, and the switching valve communicates the negative pressure inlet port and the two drain ports with each of the two negative pressure outlet ports by moving the spool.
The switching selector valve communicates with the control chamber on the opposite side of the shifter rail, and also communicates each of the two negative pressure outlet ports of the switching valve with each of the two airtight chambers partitioned by a diaphragm of the actuator. By switching the spool to 2-wheel drive or 4-wheel drive, the atmospheric inlet port or the negative pressure inlet port is selectively communicated with the control chamber of the switching valve via the outlet port, and the switching valve's negative pressure selectively communicates with the one airtight chamber through the pressure inlet port and the negative pressure outlet port,
When either one of the two drain ports is selectively communicated with the other airtight chamber via the negative pressure outlet port and the switching selector valve is used to switch to 2-wheel drive or 4-wheel drive, the emersion low gear position is set. A switching mechanism for a four-wheel drive vehicle, characterized in that it is configured to restrict shifting of a shifter rail to an emergent low gear so that it can only be obtained with four-wheel drive.