JPS62149516A - Power transmission device for automobile - Google Patents

Abstract

PURPOSE:To prevent overloading from being imposed on a power transmission system, by constituting a device so as to be selected to four-wheel drive with a high-speed driving state release signal, in case of the above-captioned device provided with a 2WD-4WD drive selector device and a sub-gear shifter. CONSTITUTION:When an input shaft 25 and an input gear 33 are engaged with each other by an engager 38 and a sub-gear shifter 31 is selected to a low-speed state, a low-speed contact point 54b comes on. Simultaneously power transmission between the input shaft 25 and a rear-wheel output shaft 29 as well as between the input shaft 25 and a rear-wheel output shaft is cut off, whereby the engager 38 comes into a neutral state. And, a high-speed contact point 54a and the low-speed contact point 54b both are turned to OFF. Therefore, in spite of selecting operation of a selector switch 49, both first and second on-off valves 43 and 46 are turned to OFF and come into a 4WD drive state by a transfer actuator 42. In addition, when the sub-gear shifter 31 releases the high speed driving state, immediately comes into 4WD drive likewise. With this constitution, such a possibility that large load is transmitted to a power transmission system is preventable.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a power transmission device for an automobile having a switching device for two-wheel and four-wheel drive, and an auxiliary transmission device capable of switching to high-speed and low-speed drive. Regarding.

(Prior Art) Recently, in order to adapt automobiles to various driving conditions, the power transmission system connecting the engine and wheels has been switched between two-wheel drive (front and rear) and four-wheel drive (one front and rear). The actuator for this switching operation is a diaphragm type actuator that operates with the engine's intake negative pressure and thereby performs the above switching (for example, Japanese Patent Laid-Open No. 59 -114132).

Also, when trying to select four-wheel drive mode,
Since the vehicle travels on a rough road such as sand or mud, it is desirable to increase the transmission torque. Therefore, some power transmission systems are provided with a sub-transmission device that enables the wheels on the drive side to be switched from a high-speed drive state to a low-speed drive state.

In the above configuration, when the two-wheel drive state is set to a low-speed drive state, the large transmission torque described above is transmitted only to the two driven wheels. However, this places an excessive load on the power transmission system connecting the engine and the wheels. For this reason, conventionally, a detection means for detecting that the sub-transmission device has selected the low-speed drive state is provided, and a detection signal from this detection means operates the actuator to switch to the four-wheel drive state, and the "uni-transmission torque" is used. There is one in which the power is distributed and transmitted to four wheels.

(Problems to be Solved by the Invention) By the way, since the above-mentioned actuator uses air pressure, due to the compressibility of air, fluid resistance, etc., it is difficult to input the detection signal from the detection means and There is a time delay, albeit a small one, in the operation until the switching operation to the wheel drive state is completed. Therefore, immediately after the auxiliary transmission selects the low-speed drive state, the switching device maintains the two-wheel drive state, and therefore, a large transmission torque is loaded on the power transmission system connecting the engine and the two driven wheels. This is not desirable.

(Object of the Invention) This invention was made with attention to the above-mentioned two hundred nineteen circumstances, and when the sub-transmission is switched to a low-speed drive state, a large transmission torque from the engine is transmitted to the front and rear wheels. The purpose is to prevent the inconvenience of being transmitted only to one wheel side and applying a large load to that transmission system.

(Structure of the Invention) A feature of the present invention for achieving the above object is that the switching device switches to the four-wheel drive state in response to a detection signal from the detection means indicating that the auxiliary transmission has released the high-speed drive state. The point is to operate the actuator as follows.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

1 is an automobile, and this automobile 1 has a drive device 2, and a front wheel device 3 and a rear wheel device 4 driven by the drive device 2.

The drive device 2 has an engine 6 and a main transmission 6' connected to the engine 6. A carburetor 7 is connected to the intake side of the engine 6.

To explain the front wheel device 3, 13, 13 are front wheels, and each front wheel 13.13 has a pair of left and right front axles 14.
14 are connected to each other. Also, this front axle 14.1
4, a front wheel differential device 15 is provided. This front wheel differential device 15 is a known one, and includes a drive pinion 16 on the input side, a pair of left and right differential side gears 17.17 on the output side, and these differential side gears 17.17.
The ring gear 18 rotates coaxially with the drive pinion 16 and meshes with the drive pinion 16.

To explain the rear wheel device 4, this 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, similar to the front wheel device 3,
This rear wheel differential device 21 has a drive pinion 22.

The engine 6 and the front and rear wheel differentials 15 and 21 are connected via 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, also transmits it to the front wheels 13.13.

The transfer 24 will be explained in more detail.

This transfer γ24 is connected to the front wheel differential device 1 via an input shaft 25 that receives power from the engine 6 and a front wheel propulsion shaft 26.
Front wheel output shaft 2 connected to drive pinion 16 of 5
7, and a rear wheel output shaft 29 connected to the drive pinion 22 of the rear wheel differential 21 via a rear wheel propulsion shaft 28 and provided coaxially with the input shaft 25.

The transfer 24 has a switching device 30 that can switch between a front and rear two-wheel drive state and a front and rear four-wheel drive state, and the drive side wheels are switched between a high-speed drive state and a low-speed drive state. It has an auxiliary transmission device 31 that can be switched to either one of the following.

First, the sub-transmission device 31 will be explained. This sub-transmission device 31 further decelerates the rotation from the main transmission device 6' and transmits it to the front wheel output shaft m15 and the rear wheel differential device 21. This sub-transmission device 31 has a transmission shaft 32 provided corresponding to the input shaft 25 and the output shaft 29 for rear wheels6, and an input gear 33 is freely rotated on the input shaft 25. A first reduction gear 34 is supported on the speed change shaft 32 so as to be freely provided and meshed with the input gear 33 . Further, a second reduction gear 35 is supported on the transmission 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. This engaging element 38 is movable in the axial direction via a manual shift lever (not shown), and by its axial movement, the input shaft 25 and the rear wheel output shaft 29 are directly connected, or the input shaft 25 and the input gear 33 are connected.

39 is a chain transmission means; this chain transmission means 39
The output gear 36 and the front wheel output shaft 27 are connected to each other.

Further, the switching device 30 is provided with a transfer clutch 40 that connects and disconnects power transmission from the rear wheel output shaft 29 to the output gear 36.

Then, as shown by the solid line in the figure, the retainer 38 is operated to connect the input shaft 25 and the rear wheel output shaft 29, and the transfer clutch 40 is operated to connect the rear wheel output shaft 29 and the output gear 36. When these are disconnected, the power of the engine 6 is transmitted at high speed only to the rear wheels 19 and 19 via the rear wheel differential 21. That is, this is a high-speed two-wheel drive state.

The input shaft 25 and the output shaft 2 for rear wheels are connected by operating the engaging element 38 same as above.
9 (shown by the solid line in the figure), and operate the transfer clutch 40 to connect the rear wheel output shaft 29 and the output gear 36.
(as shown by the two-dot chain line in the figure), the power from the engine 6 is transmitted to the rear wheels 19.1 at high speed via the rear wheel differential 21.
The power of the engine 6 is transmitted to the front wheels 13 and 13 via the front wheel differential 15. That is,
This is considered a high-speed four-wheel drive state.

Further, as shown by the two-dot chain line ° in the figure, the above engaging element 38 is operated to connect the input shaft 25 and the input gear 33, and the transfer clutch 40 is operated to connect the rear wheel output shaft 29 and the output gear 36. When these are connected, first, the power of the input shaft 25 is decelerated by each gear 33 to 36, and this decelerated power is transmitted to the front and rear wheels 13 through the front and rear wheel differentials 15 and 21.
It is transmitted to ゜19. That is, this is a low-speed four-wheel drive state.

A diaphragm transfer actuator 42 is provided to connect and disconnect the transfer clutch 40. In the transfer actuator 42, one chamber 42a partitioned off by a diaphragm is communicated with the atmosphere via a first on-off valve 43. This first on-off valve 43
is a 3-boat, 2-position solenoid valve, and the solid line indicates the state in which the solenoid is OFF, and the dashed-dotted line indicates the state in which the solenoid is ON. In this first on-off valve 43, a third port other than the port connected to the one chamber 42a and the atmosphere side is connected to the downstream side of the carburetor 7 via a check valve 44, that is, the intake negative side of the engine 6. Connected to areas with high pressure.

Further, the other chamber 42b of the transfer actuator 42 is connected to the downstream side of the carburetor 7 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 boat is communicated with the atmosphere.

Both the first on-off valve 43 and the second on-off valve 46 are normally on, and the transfer actuator 4
One of the chambers 42a of the transfer actuator 42 is connected to the downstream side of the carburetor 7 by the first on-off valve 43 to make it negative and positive, and the other chamber 42b of the transfer actuator 42 is connected to the atmosphere side by the second on-off valve 46. They are in communication with each other, and the transfer actuator 42 is operated by the differential pressure between them. In conjunction with this transfer actuator 42, the transfer clutch 40 operates on the rear wheel output shaft 29.
Power transmission from the output gear 36 to the output gear 36 is cut off (indicated by a solid line in the figure). In this way, the two-wheel drive state described above can be obtained.

Well, contrary to the above, the first on-off valve 43 and the second on-off valve 46
If both are turned off, contrary to the above, one chamber 42a of the transfer actuator 42 is communicated with the atmosphere, and the other chamber 42b is connected to the downstream side of the carburetor 7 and has a negative pressure. The transfer actuator 42 is actuated by these differential pressures.The transfer clutch 40 connects the rear wheel output shaft 29 and the output gear 36 in conjunction with the transfer actuator 42 (
(Illustrated with chain double-dashed lines in the figure). In this way, the four-wheel drive state described above can be obtained.

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

48 is a power source, and a changeover switch 49 is connected to this power source 48. This changeover switch 49 is a switch for selecting two-wheel drive (2WD) and four-wheel drive (4WD).
It has a wheel drive circumferential contact 49a and a four-wheel drive circumferential contact 49b. A first on-off valve 43 and a second on-off valve 46 are connected to the two-wheel drive contact 49a.

On the other hand, a limit switch 51 is provided that detects the operation of the transfer clutch 40 when the four-wheel drive state is established by the operation of the transfer clutch 40. This limit switch 51 has a normally open contact 51a, and is turned on when the above-mentioned four-wheel drive state is detected. Further, 52 is an indicator light for indicating the four-wheel drive state, and the contact 51a and this indicator light 52 are connected in series to the power source 48.

Then, by operating the changeover switch 49, the two-wheel drive peripheral contact 49
When a is connected to the power source 48, both the first on-off valve 43 and the second on-off valve 46 are turned on, and thereby the transfer actuator 42 operates the transfer clutch 40 to connect the rear wheel output shaft 29 and the output gear. 36 is disconnected, the power of the engine 6 is transmitted only to the rear wheels 19 and 19, and a two-wheel drive state is obtained. In this case, the contact 51a of the limit switch 51 is turned off (shown by the solid line in the figure), so the indicator light 52 is turned off.

On the other hand, by operating the changeover switch 49, the four-wheel drive peripheral contact 49b
When connected to the power supply 48, both the first on-off valve 43 and the second on-off valve 46 are turned off, and thereby the transfer actuator 42 operates the transfer clutch 40 to connect the rear wheel output shaft 29 and the output gear 36. The power of the engine 6 is transmitted to the front wheels 13, 13 in addition to the rear wheels 19, 19, resulting in four-wheel drive. in this case,
Since the contact 51a of the limit switch 51 is turned on (indicated by the two-dot chain line in the figure), the indicator light 52 lights up to indicate that the vehicle is in a four-wheel drive state.

In the above configuration, a device is provided to prevent the vehicle from entering a two-wheel drive state when the sub-transmission device 31 is brought into a low-speed drive state.

This device will be explained below.

54 is a limit switch, and this limit switch 54
is a detection means for detecting a switching state of the sub-transmission device 31 from a high-speed drive state to a low-speed drive state, and this detection is performed by detecting the operation of the engaging element 38. The limit switch 54 has a high speed contact 54a and a low speed contact 5.
4b, the high-speed contact 54a is interposed between the power supply 48 and the changeover switch 49, and the low-speed contact 54b is interposed between the power supply 48 and the contact 51a of the limit switch 51.

The engagement element 38 is connected to the input shaft 25 and the rear wheel output shaft 2.
9 to bring the sub-transmission device 31 into a high-speed state, it engages with this engager 38 and turns on the high-speed contact 54a (shown by the solid line in the figure). 2
5 and the input gear 33 are connected to bring the auxiliary transmission 31 into a low speed state, it engages with this engager 38 and the low speed contact 54
b is turned on (indicated by a chain double-dashed line in the figure). In addition, at the time of transition between the high-speed drive state and the low-speed drive state, the input shaft 25
and the rear wheel output shaft 29, and the power transmission between the input shaft 25 and the rear wheel output shaft 29 are disconnected, and the engager 38 is in a neutral state. In this case, this engaging element 3
8 is released, and both the high-speed contact 54a and the low-speed contact 54b are turned off (indicated by a chain line in the figure).

Therefore, when the sub-transmission device 31 is in a high-speed drive state, that is, when the high-speed contact 54a is on, the two-wheel drive state or the four-wheel drive state can be freely selected by operating the selector switch 49. be done. On the other hand, when the sub-transmission device 31 is in a low-speed driving state, that is, when the high-speed contact 54a is turned off, the changeover switch 4
Regardless of the switching operation in step 9, both the first on-off valve 43 and the second on-off valve 46 are turned off, and the transfer actuator 42 interlocked therewith brings the vehicle into a four-wheel drive state.

Furthermore, when the sub-transmission device 31 releases the high-speed drive state, the high-speed contact 54a is immediately turned off, so as described above, both the first on-off valve 43 and the second on-off valve 46 are turned off, and the associated transfer The actuator 42 brings the vehicle into a four-wheel drive state.

(Effects of the Invention) According to the present invention, the actuator is actuated so that the switching device switches to the four-wheel drive state in response to a detection signal from the detection means indicating that the sub-transmission device has released the high-speed drive state. When changing from the high speed drive state to the low speed drive state, the switching operation by the actuator to the four wheel drive state is started from the moment the high speed drive state is released. Therefore, even if it takes some time from the start to completion of the actuator switching operation to change from a two-wheel drive state to a four-wheel drive state, it is within the time required to switch from a high-speed drive state to a low-speed drive state. Then, the switching operation of the actuator can be completed. Therefore, when the auxiliary transmission is switched to the low-speed drive state, the large transmission torque from the engine caused by the low-speed drive state is transmitted only to the two driven wheels, placing a large load on the power transmission system. The occurrence of the inconvenience of giving is suppressed.

[Brief explanation of drawings]

The figure is an overall view showing an embodiment of the invention. lee car, 61111 engine, 13.13-・Front wheel, 19,19・・Rear wheel, 24・・Transfer, 30
...Switching device, 31...Sub-transmission device, 42!・Transfer actuator (actuator).

Claims (1)

[Claims] 1. The power transmission system that connects the engine and the front and rear wheels is equipped with a switching device that enables switching between two-wheel drive (front and rear) and four-wheel drive (front and rear), and a switching device that enables switching between front and rear 2-wheel drive and front and rear 4-wheel drive. An automobile is provided with an auxiliary transmission capable of switching between a high-speed drive state and a low-speed drive state, an actuator for switching the switching device, and a detection means for detecting the switching state of the auxiliary transmission. A power transmission device for an automobile, characterized in that the switching device operates an actuator to switch to a four-wheel drive state in response to a detection signal from the detection means indicating that the sub-transmission device has released the high-speed drive state. Device.