JP2599965B2 - 4 wheel drive vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a four-wheel drive vehicle provided with a center differential.

2. Description of the Related Art Conventionally, as a four-wheel drive vehicle, a torque limiter that operates when a predetermined torque or more is applied and interrupts the transmission of torque is provided in one of a front wheel drive system and a rear wheel drive system. There is one in which the drive system after the limiter is reduced in weight (see Japanese Utility Model Application Laid-Open No. S61-106436).

Further, in the four-wheel drive vehicle, a center differential for dividing the driving force output from the engine and transmitting the divided driving force to the front wheel drive system and the rear wheel drive system is provided.
There is one that improves running performance during cornering.

[Problems to be solved by the invention]

In a four-wheel drive vehicle equipped with the above-mentioned torque limiter and not directly equipped with a center differential, for example, when a torque limiter is provided in a rear wheel drive system, when a sudden start or a sudden acceleration is to be performed, the torque is reduced. The torque limiter operates by applying a predetermined torque or more to the limiter, and the torque is not transmitted at the torque limiter. In this case, the driving force of the engine is not transmitted to the rear wheels,
Since the driving force of the engine is transmitted to the front wheels, sudden start and sudden acceleration can be performed.

However, in a four-wheel drive vehicle further equipped with a center differential, if the torque limiter is actuated and torque is no longer transmitted at the torque limiter, the rear wheel drive system is not loaded with respect to the center differential. Due to the characteristics of the differential, the driving force of the engine escapes to the rear wheel drive system, and the driving force of the engine is not transmitted to the front wheels as well as to the rear wheels where the torque limiter does not transmit the driving force of the engine. . For this reason, in a four-wheel drive vehicle equipped with a torque limiter and a center differential, sudden start or sudden acceleration as operated by the torque limiter could not be performed, and the startability and running performance were not good.

In view of the above circumstances, the present invention provides a four-wheel drive vehicle equipped with a center differential, which can use a torque limiter to reduce the weight of a drive system after the torque limiter and improve startability and running performance. An object of the present invention is to provide a four-wheel drive vehicle that can be used.

[Means for solving the problem]

In order to solve the above problems, a four-wheel drive vehicle according to the present invention is a four-wheel drive vehicle provided with a center differential for dividing a driving force output from an engine and transmitting the divided driving force to a front wheel drive system and a rear wheel drive system. A torque limiter that operates when a predetermined torque or more is applied and interrupts the transmission of torque is provided in one of the front wheel drive system and the rear wheel drive system, and the difference between the center differential when the torque limiter is operating is provided. A center differential limiting means for limiting the movement is provided.

[Action]

According to the above configuration, when the torque limiter operates,
The differential of the center differential is limited by the center differential limiting means. For this reason, during the operation of the torque limiter, the center differential hardly operates, and the state becomes the same as that of the direct connection type having no center differential. Therefore, sudden start and sudden acceleration can be performed.

〔Example〕

FIG. 1 shows an embodiment of a four-wheel drive vehicle according to the present invention. This four-wheel drive vehicle splits an engine 1, a transmission 2 connected to the engine 1, and a driving force output from the engine 1 via the transmission 2 to the drive system 3 and the rear wheel drive system 4. And a center differential 5.

The front wheel drive system 3 includes a front wheel 31, a front wheel axle 32, and a front differential 33. The rear wheel drive system 4 includes a rear wheel 41,
It has a rear wheel axle 42, a rear differential 43, and a prop shaft 44. The center differential 5
The first side gear 51 is provided on a front wheel axle 32 and is connected to a binion gear 33a of a front differential 33 via a front wheel side connecting member 52.
3 is connected to a pinion gear 44a of the propeller shaft 44 via a rear wheel side connecting member 54.

A part of the rear wheel side connecting member 54 includes a sleeve driving motor 6.
The center differential lock sleeve 7 is slidably engaged. When the sleeve 7 for the center differential lock is slid to the left in the figure by the sleeve drive motor 6, the sleeve 7 also engages with a pinion gear connecting member 55 connected to the pinion gear 50 of the center differential 5.

The propeller shaft 44 of the rear wheel drive system 4 is divided on the way into an input side shaft 44b and an output side shaft 44c, and a distance between the input side shaft 44b and the output side shaft 44c is not less than a predetermined value. A torque limiter 8 that operates when torque is applied and interrupts the transmission of torque is provided.

The torque limiter 8 is configured as shown in FIG. 2 and FIG. Reference numeral 81 denotes a main shaft. The main shaft 81 is connected to an output shaft 44c of the propeller shaft 44 via a bearing retainer 82. A flange 83 is formed at one end of the main shaft 81.
In 83, one end of the input shaft 44b of the propeller shaft 44 is abutted, and a plurality of through holes 84 are formed at equal intervals in the circumferential direction. A steel ball 85 is inserted into each through-hole 84, and the steel ball 85 is constantly urged toward the butting surface of one end of the input shaft 44b by a pressure plate 87 to which the spring force of a disc spring 86 is applied. Have been.

A plurality of conical recesses 88 are formed at equal intervals in the circumferential direction on the butting surface of one end of the input shaft 44b, and each of the conical recesses 88 is urged by a spring force of a disc spring 86 in each of the conical recesses 88. Steel ball 85 is fitted. For this reason, normally, that is, when the torque transmitted between the input-side shaft 44b and the output-side shaft 44c is equal to or less than a predetermined value, the input-side shaft 44b and the main shaft 81 The driving force of the engine is transmitted from the input shaft 44b to the output shaft 44c.

On the other hand, when the torque transmitted between the input side shaft 44b and the output side shaft 44c exceeds a predetermined value, the steel ball 85 can be held in the conical recess 88 by the spring force of the disc spring 86. Then, the steel ball 85 is pushed out of the conical recess 88, and the input side shaft 44b rotates while sliding with respect to the main shaft 81. Therefore, the driving force of the engine is not transmitted from the input shaft 44b to the output shaft 44c.

When an excessive torque is input to the torque limiter 8 in this manner, the driving force of the engine 1 is not transmitted to the drive system such as the output shaft 44c of the propeller shaft 44 and the rear wheel axle 42 after the torque limiter 8. Therefore, the torque limiter 8
Excessive torque is not applied to each component of the drive system thereafter. For this reason, even if the rigidity of each component of the drive system after the torque limiter 8 is reduced, these components will not be damaged, and the drive system can be reduced in weight.

When the torque limiter 8 is actuated as described above and the steel ball 85 is pushed out of the conical depression 88, the pressure plate 87 is pushed by the steel ball 85 and retreats toward the disc spring 86. A torque limiter sensor 9 for detecting whether or not the torque limiter 8 is operating is attached to a case 89 of the torque limiter 8.
When the torque limiter 8 is actuated and the pressure plate 87 is retracted, the pressure plate 87 contacts the terminal 91 of the torque limiter sensor 9 so that the torque limiter sensor 9 detects that the torque limiter 8 is operating. It has become.

The torque limiter sensor 9 includes a control unit 10
When the torque limiter 8 is detected to be in operation, a torque limiter operation detection signal is output to the control unit 10. When the torque limiter operation detection signal is input from the torque limiter sensor 9, the control unit 10 outputs a center differential lock command signal to the sleeve drive motor 6. Then, the sleeve 7 for center differential lock is slid to the left in FIG. 1 by the sleeve drive motor 6 receiving the signal. Accordingly, the pinion gear connecting member 55 connected to the pinion gear 50 of the center differential 5 and the rear wheel side connecting member 54 connected to the second side gear 53 of the center differential 5 are connected, and the differential of the center differential 5 is limited. Will be done. That is, the sleeve drive motor 6 and the center differential lock sleeve 7 serve as center differential differential limiting means.

When the torque limiter operation detection signal is no longer output from the torque limiter sensor 9, the control unit 10 outputs a center differential lock release command signal to the sleeve drive motor 6. And
The center differential lock sleeve 7 is slid rightward in FIG. 1 by the sleeve drive motor 6 receiving the signal. As a result, the connection between the pinion gear connecting member 55 and the retreating side connecting member 54 is released, and the center differential 5 comes to be differential as intended.

As described above, in the four-wheel drive vehicle, the differential of the center differential 5 is limited while the torque limiter 8 is operating. For this reason, during the operation of the torque limiter 8, the center differential 5 does not perform its original function, and is in the same state as when the center differential 5 is not provided, and both the front wheel drive system 3 and the rear wheel drive system 4 Also, the driving force of the engine 1 is transmitted. Therefore, an excessive torque is applied to the torque limiter 8 in an attempt to make a sudden start, etc.
Even if the driving force of engine 1 is no longer transmitted to 41,
The driving force transmitted to 31 makes it possible to start suddenly. It should be noted that the sleeve drive motor 9 may be separately controlled by a driver's operation so that the differential restriction of the center differential 5 and the release thereof can be performed by an arbitrary switching operation of the driver.

In the above-described embodiment, whether or not the torque limiter 8 is operating is electrically detected to control the center differential limiting device. However, the center differential limiting device is controlled by a mechanical method as described below. May be.

In the four-wheel drive vehicle shown in FIG. 4, a torque limiter 11 having the same structure as the above embodiment is used. The torque limiter 11 is located on the front axle 32 and
It is interposed between the input-side member 54a and the output-side member 54b of the split rear wheel-side connecting member 54 (part of the rear wheel drive system 4). A wet multi-plate clutch 12 is used as the center differential limiting means.
Reference numeral 12 is interposed between the pinion gear connecting member 55 and the input side member 54a of the rear wheel side connecting member 54. Wet multi-plate clutch 1
The two clutch plates 12a are open when the torque limiter 11 is not operating. However, when the torque limiter 11 is actuated, the pressure plate 11b urged by the spring force of the disc spring 11a is pushed by the steel ball 11c and retreats leftward in the drawing.
Accordingly, a large number of clutch plates 12a are closed. Therefore, during the operation of the torque limiter 11, the input side member 54a of the rear wheel side connecting member 54 connected to the pinion gear connecting member 55 connected to the pinion gear 50 of the center differential 5 and the second side gear 53 of the center differential 5 Are connected via the wet type multi-plate clutch 12, and the differential of the center differential 5 is limited. In the drawings, FIGS.
The components denoted by the same reference numerals as those in the drawings indicate the same components as those described in the above embodiment.

FIG. 5 shows another example of the torque limiter and the center differential limiting means. In the figure, 13 is a transfer case, 14 is an input shaft connected to a second side gear (not shown) of a center differential, and 15 is an output shaft connected to a propeller shaft (not shown). One end of the output shaft 15 is inserted into a concave portion 14a formed in the input shaft 14, and a plurality of conical recesses 15b are formed on its outer peripheral surface 15a at equal intervals in the circumferential direction.
To one end of the input shaft 14, an end of a friction plate 16 bent along the outer peripheral surface 14b is swingably attached. A notch 17 is attached to the other end of the friction plate 16 with its warhead-shaped head facing the outer peripheral surface 15a of one end of the output shaft 15.

Normally, that is, when the torque transmitted between the input shaft 14 and the output shaft 15 is equal to or less than a predetermined value, the warhead of the notch 17 attached to one end of the input shaft 14 It is fitted into a conical recess 15b formed in the outer peripheral surface 15a of the portion, and is held in that state by the spring force of the coil spring 18. Therefore, at this time, the input shaft 14 and the output shaft 15 rotate integrally, and the driving force of the engine is reduced by the input shaft.
From 14 is transmitted to the output shaft 15.

When the torque transmitted between the input shaft 14 and the output shaft 15 exceeds a predetermined value, the warhead head of the notch 17 cannot be held in the conical recess 15b due to the spring force of the coil spring 18, The input shaft 14 rotates while sliding with respect to the output shaft 15, so that the driving force of the engine is not transmitted from the input shaft 14 to the output shaft 15. And
At the same time, the warhead of the notch 17 extends on the outer peripheral surface 15a at one end of the output shaft 15, and the notch 17 is pushed outward. A friction plate 19 is attached to the inner surface of the transfer case 13 so as to surround one end of the input shaft 14,
When the notch 17 is pushed out, the friction plate 16 to which the notch 17 is attached comes to be pressed against the friction plate 19 of the transfer case 13, and the frictional force generated between the two friction plates 16, 19 causes the input shaft 14 to be pressed. The braking force is applied. Therefore, this braking force acts as a load on the second side gear of the center differential connected to the input shaft 14, and the differential of the center differential is limited. In the above configuration, the input shaft 14, the output shaft 15, the notch
The 17 and the coil spring 18 constitute a torque limiter, and the two friction plates 16, 19 constitute a center differential limiting means.

As shown in this example, a load is generated in the drive system provided with the torque limiter by the center differential limiting means, and this load is applied to the side gear of the center differential connected to the drive system.
The differential of the center differential may be limited. If the torque limiter and the center differential limiting means are configured as shown in this example, it is possible to reduce the size.

The torque limiter used in the present invention may be of a hydraulic type. Further, the torque that starts to operate may be arbitrarily changed. In short, it is only necessary to interrupt the transmission of torque when a predetermined torque or more is applied. The center differential differential limiting means is not limited to the above embodiment as long as it limits the differential of the center differential during the operation of the torque limiter.
In order to limit the differential of the center differential, the center differential may not be operated at all as shown in FIGS. 1 to 4, or the center differential may not be operated as shown in FIGS. 5 and 6. Work may be suppressed. Further, the torque limiter may be provided in the front wheel drive system or may be provided in the rear wheel drive system.

〔The invention's effect〕

As described above, in the four-wheel drive vehicle according to the present invention, since the torque limiter is provided in one of the front wheel drive system and the rear wheel drive system, excessive torque is applied to the drive system after the torque limiter. Will not be applied. Therefore, it is not necessary to increase the rigidity of each component of the drive system after the torque limiter, and the weight can be reduced. In addition, during the operation of the torque limiter, the differential of the center differential is limited by the center differential differential control means, so that a sudden start or a sudden acceleration can be performed, and the startability and traveling performance are improved. .

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a schematic configuration of an embodiment of a four-wheel drive vehicle according to the present invention, FIG. 2 is a sectional view showing a torque limiter thereof, FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 4 is a skeleton diagram showing a schematic configuration of another embodiment, FIG. 5 is a sectional view showing a torque limiter and a center differential limiting device of still another embodiment, and FIG.
It is a VI-VI sectional view. 1 ... Engine, 3 ... Front wheel drive system, 4 ... Rear wheel drive system, 5 ... Center differential, 6, 7, 12 ... Center differential differential limiting means, 8, 11 ... Torque limiter.

Claims (1)

(57) [Claims] 1. A four-wheel drive vehicle having a center differential for dividing a driving force output from an engine and transmitting the divided driving force to a front wheel drive system and a rear wheel drive system. A torque limiter that interrupts transmission of the torque is provided in one of the front wheel drive system and the rear wheel drive system, and a center differential limiter that limits the differential of the center differential when the torque limiter is operating. A four-wheel drive vehicle characterized by comprising means.