JPS62149515A - Power transmission device for automobile - Google Patents

Abstract

PURPOSE:To prevent large load from being imposed on a power transmission system, by constituting a device in making a selector device interlock with a sub-gear shifter so as to be selected to four-wheel drive with low-speed driving select operation, in case of a device, bearing the above caption, having the 2WD-4WD drive selector device and the sub-gear shifter. CONSTITUTION:When a shift arm 47 is selected from a neutral position as in a dashed line to a low-speed driving state shown in a two-dot chain line, an extension part 47a of the shift arm 47 is engaged with an engaging piece 71 of a transfer fork 54 in the midway, making this transfer fork 54 forcibly into slide motion. With this operation, a selector device 30 comes into a 4WD drive state shown in the two-dot chain line. In this case, when a sub-gear shifter 31 is in a high-speed driving state, the transfer fork 54 is movable without being checked by the engaging piece 71, whereby selection of 4WD and 2WD can be freely performed by a selector switch 69. With this constitution, such a fear that large load might be imposed on a 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 (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).

In addition, when trying to select the four-wheel drive state, 1.
Since the road the vehicle travels on is rough, such as sandy or muddy ground, 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 is provided for detecting that the sub-transmission has selected the low-speed drive state, and a detection signal from the detection means operates the actuator to switch to the four-wheel drive state, thereby increasing the transmission torque. There is one that distributes the transmission 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 circumstances, and when the sub-transmission is switched to a low-speed drive state,
To prevent the inconvenience of a large transmission torque from an engine being transmitted only to one of the front and rear wheels and applying a large load to the transmission system.

(Structure of the Invention) A feature of the present invention for achieving the above object is that when the sub-transmission is switched to the low-speed drive state, the switching device switches to the four-wheel drive state. The point is that the switching devices are linked.

(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 Q. 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 mechanism 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, like the front wheel device 3, has a pair of left and right rear wheels 19.19. Consists of a rear axle 20.20 and a rear wheel differential 21,
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 24 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 auxiliary transmission 31 will be explained. This auxiliary transmission 31 further decelerates the rotation from the main transmission 6' and transmits it to the front wheel differential 15 and the rear wheel differential 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 width. 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 on the speed change shaft 32, and an output gear 36 is rotatably provided on the rear wheel output shaft 29 so as to mesh with the first reduction gear 34.

The input shaft 25 is provided with an engaging element 38 that is slidable in the axial direction. This retainer 38 is movable in the axial direction, and by moving in the axial direction, the input shaft 25 and the rear wheel output shaft 2
9 are directly connected, or the input shaft 25 and the input gear 33 are connected. 39 is a chain transmission means, and this chain transmission means 39 connects the output gear 36 and the front wheel output shaft 27.

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 a solid line in the figure), and operate the transfer clutch 40 to connect the rear wheel output shaft 29 and the output gear 3.
6 (indicated by the chain double-dashed line in the figure), the engine 6
The power is transmitted to the rear wheels 19 through the rear wheel differential device 21 at high speed.
19, and the power of the same engine 6 is transmitted to the front wheels 13 and 13 via the front wheel differential 15. That is, this is 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 and 19 via the front and rear wheel differentials 15 and 21. transmitted to. That is, this is a low-speed four-wheel drive state.

Among the operating systems of the engaging element 38 and transfer clutch 40, the operating system of the retainer 38 will be described first.

A shift fork 42 is engaged with the engaging element 38. This shift fork 42 is connected to the transfer case 24a.
The support shaft 43 is externally fitted so as to be slidable in the axial direction, and the support shaft 43 has an axis parallel to the axis of the engaging element 38 .

On the other hand, the shift arm 4 is linked via a push-pull cable 45 to a shift lever 44 for switching between high and low speed drives.
7 is provided. This shift arm 47 is pivotally supported by the transfer case 24a via a pivot shaft 48, and its rotating end is connected to a retaining portion 49 projecting from the shift fork 42.
is engaged in. Further, 50 is an arm for rotating the pivot shaft 48, and one end side of this arm 50 is connected to the push-pull cable 45.

When the shift arm 47 is rotated as shown by the solid line in the figure by operating the shift lever 44, the shift fork 42 slides on the support shaft 43, thereby causing the engager 38 to rotate.
connects the input shaft 25 and the rear wheel output shaft 29. As a result, the sub-transmission device 31 is switched to the high-speed driving state.

On the other hand, if the shift arm 47 is rotated as shown by the two-dot chain line in the figure by operating the shift lever 44, the shift fork 42 slides on the support shaft 43 in the same manner as described above, and thereby the engaging element 38 connects the input shaft 25 and the input gear 33. As a result, the sub-transmission device 31 is switched to the low-speed drive state.

Furthermore, during the transition between the high-speed drive state and the low-speed drive state, the shift arm 47 is in a neutral position. That is, as shown by the dashed line in Figure 1, the input shaft 25 and the rear wheel output shaft 2
9, and each power transmission between the input shaft 25 and the input gear 33 is cut off, and the engager 38 is in a neutral state.

In Figure 2, 52 is a limit switch.

This limit switch 52 is for detecting each state of high speed and low speed driving of the sub-transmission device 31, and this detection is made by detecting the operation of the engaging portion 49.

Next, the operation system of the transfer clutch 40 will be explained. A transfer fork 54 is engaged with the transfer clutch 40, and the transfer fork 54 is supported by a fork shaft 55 so as to be slidable in the axial direction. This fork shaft 55 has an axis parallel to the axis of the transfer clutch 40 and is supported by the transfer case 24a. Further, a spring 58 is provided between the transfer fork 54 and the fork shaft 55 to bias the transfer fork 54 in a direction to disconnect the rear wheel output shaft 29 and the output gear 36. Further, a retaining ring 59 is attached to the fork shaft 55 to prevent the transfer fork 54 from sliding more than a predetermined amount with respect to the fork shaft 55 due to this bias.

A diaphragm transfer actuator 62 for operating the fork shaft 55 is provided. In the transfer actuator 62, one chamber 62a partitioned off by a diaphragm is communicated with the atmosphere via a first on-off valve 63. This first on-off valve 63 is a 3-boat, 2-position solenoid valve that turns off the solenoid (O
The solid line indicates the state in which the solenoid is turned on (FF).
N) is shown by the two-dot chain line. In this first on-off valve 63, a third boat other than the one connected to the one chamber 62a and the atmosphere side is a check valve 6.
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 62b of the transfer actuator 62 is connected to the downstream side of the carburetor 7 via a second on-off valve 66. This second on-off valve 66 has the same configuration as the first on-off valve 63, and its third boat is communicated with the atmosphere.

Both the first on-off valve 63 and the second on-off valve 66 are normally on, and the transfer actuator 6
One chamber 62a of the transfer actuator 62 is communicated with the downstream side of the carburetor 7 by the first on-off valve 63 to have a negative pressure, and the other chamber 62b of the transfer actuator 62 is communicated with the atmosphere side by the second on-off valve 66. The transfer actuator 62 is operated by the pressure difference between them. The fork shaft 55 slides in conjunction with the transfer actuator 62, and the transfer clutch 40 transmits power from the rear wheel output shaft 29 to the output gear 36 via the transfer fork 54 accompanying the fork shaft 55. (shown by the solid line in the figure). By doing this, it is possible to obtain the two-wheel drive state as described above.

Also, the above is reverse L', the first on-off valve 63 and the second on-off valve 6
6 are both turned off, contrary to the above, one chamber 62'a of the transfer actuator 62 is communicated with the atmosphere, and the other chamber 62b is connected to the downstream side of the carburetor 7, thereby creating a negative pressure. The transfer actuator 62 is actuated by these differential pressures. The fork shaft 55 slides in conjunction with the transfer actuator 62, and the transfer clutch 40 connects the rear wheel output shaft 29 and the output gear 36 via the transfer fork 54 that accompanies the fork shaft 55. (Indicated by the chain double-dashed line 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.

68 is a power source, and a changeover switch 69 is connected to this power source 68. This changeover switch 69 is a switch for selecting two-wheel drive (2WD) and four-wheel drive (4WD).
It has a wheel drive peripheral contact 69a and a four-wheel drive contact 69b. A first on-off valve 63 and a second on-off valve 66 are connected to the two-wheel drive liquid point 69a.

Then, by operating the changeover switch 69, the two-wheel drive contact 69
When a is connected to the power source 68, both the first on-off valve 63 and the second on-off valve 66 are turned on, and thereby the transfer actuator 62 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.

On the other hand, by operating the changeover switch 69, the four-wheel drive contact 69b
When connected to the power supply 68, both the first on-off valve 63 and the second on-off valve 66 are turned off, and thereby the transfer actuator 62 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 and 13 in addition to the rear wheels 19 and 19, resulting in four-wheel drive.

In FIG. 2, 60 is a limit switch, and this limit switch 60 is for detecting each switching state of the 2° four-wheel drive of the switching device 30, and this detection is for detecting the operation of the fork shaft 55. It is done by.

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

This means will be explained below.

A portion of the shift arm 47 is connected to the transfer fork 5.
4, while the transfer fork 54
An engagement piece 71 is provided to protrude from.

This engaging piece 71 is provided as follows. That is, during the period from the posture of the shift arm 47 that brings the sub-transmission device 31 into the neutral driving state (shown by the dashed-dot line in the figure) to the posture of the shift arm 47 that puts the sub-transmission device 31 into the low-speed driving state (shown by the chain double-dashed line in the figure). The extending portion 47a of the shift arm 47 engages with the engagement piece 71. With this engagement, the transfer fork 54 is forced to slide, thereby causing the switching device 30
is in a four-wheel drive state (indicated by a chain double-dashed line in the figure).

In the above case, when the sub-transmission device 31 is in a high-speed drive state, that is, when the shift arm 47 is rotated to the high-speed drive position (as shown by the solid line in the figure), the engagement piece 71 The transfer fork 54 is allowed to move without being hindered, and by operating the changeover switch 69, the two-wheel or four-wheel drive state can be freely selected.

(Effects of the Invention) According to the present invention, the switching device is linked to the auxiliary transmission so that the switching device switches to the four-wheel drive state when the auxiliary transmission is switched to the low-speed drive state. If the driver selects the low-speed drive state, the switching device is reliably prevented from entering the two-wheel drive state. 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 figures show an embodiment of the present invention, in which Fig. 1 is an overall view, Fig. 2 is a sectional view of a transfer, and Fig. 3 is a section taken along line III-m in Fig. 2.
It is a line arrow view. 1-・Automobile, No. 6 engine, 13.13・・Front wheel,
19.19... Rear wheel, 30... Switching device, No. 3111 sub-transmission device.

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. In a power transmission system for an automobile equipped with an auxiliary transmission capable of switching between a high-speed drive state and a low-speed drive state, the switching device switches to a four-wheel drive state when the auxiliary transmission is switched to a low-speed drive state. A power transmission device for an automobile, characterized in that a switching device is interlocked with a sub-transmission device so as to change the transmission.