JP4246301B2 - Four-wheel drive device for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drive train of a four-wheel drive device for a vehicle, and more particularly to a power distribution device that distributes driving force to front wheels and rear wheels.
[0002]
[Prior art]
Conventionally, many power distribution devices for vehicle four-wheel drive devices have been proposed in which a differential gear device is combined with a differential limiting device.
[0003]
However, a power distribution device (center differential device) in which a differential gear device is combined with a differential gear device generally has a complicated structure and is expensive. For example, Japanese Patent Publication No. 48-3971 The publication discloses a multi-output path torque transmission device (driving force transmission device) in which a planetary gear type differential gear device is provided with a one-way clutch. According to this technique, the front wheel is allowed to rotate considerably faster than the rear wheel during forward traveling without using a complicated differential limiting device, and the rear wheel is slightly smaller than the front wheel. The front and rear wheels can be differentially limited so that the vehicle can only turn faster than the value (the value necessary to correct the difference in the effective radius of the tire). In addition, this multi-output road torque transmission device has a one-way clutch in the front wheel output shaft system, and this one-way clutch is weakly engaged during reverse running to prevent a tight corner braking phenomenon during turning.
[0004]
In the full-time 4WD power distribution device, the forward and reverse one-way clutches are arranged on the transfer bevel gear shaft, and the sleeve can be selectively coupled to the outer peripheral spline of the one-way clutch. By doing so, a technique for limiting the differential at the time of forward and backward movement by the differential gear device to only one direction has been put into practical use.
[0005]
On the other hand, a full-time 4WD power distribution device using a differential gear device is disadvantageous in terms of weight, cost, size, etc. Further, if a differential lock mechanism is added as a differential limiting device, the overall device becomes complicated. Therefore, for example, Japanese Utility Model Publication No. 61-81428 discloses a non-steering wheel output shaft having one end connected to an engine output shaft via a transmission and the other end connected to a non-steering wheel; A steering wheel output shaft that is juxtaposed with the non-steering wheel output shaft and connected to the steering wheel, and a driving force from the non-steering wheel output shaft that is assembled to the steering wheel output shaft and the non-steering wheel output shaft. Output shaft coupling means capable of transmitting the steering wheel output shaft to the steering wheel output shaft, and the output shaft coupling means is rotatably supported via a bearing and allows a forward rotation of the steering wheel ( One way ) And, the one-way clutch wherein the non-steered wheel output shaft and the clutch operation unit that can be integrated with the annexed has been has four wheel drive power transmission device is disclosed. The four-wheel drive power transmission device automatically avoids the tight corner braking phenomenon when a rotational difference occurs between the front wheels and the rear wheels during turning.
[0006]
Japanese Patent Laid-Open No. 3-217333 discloses that the front wheel drive shaft is directly connected to the rear wheel drive shaft when the rotation of the front wheels is slower than the rotation of the rear wheels, and is not directly connected when the rotation of the front wheels is faster than the rotation of the rear wheels. Discloses a four-wheel drive device including a one-way clutch and a differential limiting mechanism that is interposed between the drive shafts of the front and rear wheels and absorbs a difference in rotational speed between the front and rear wheels when the drive shafts are directly connected. .
[0007]
[Problems to be solved by the invention]
However, each of the above technologies has the following problems.
First, in the technique described in the above Japanese Patent Publication No. 48-3971, if the rear wheel slips during straight running and slips more than the preset gear ratio of the front wheel drive system, the one-way clutch is locked and moved back and forth. The wheel is engaged to be in a direct connection 4WD state. Therefore, this center differential device is differentially locked according to the slip of the front and rear wheels, but when the weight distribution of the vehicle, the vehicle specifications, the variation of the effective radius of the tire and the change of wear and air pressure, puncture, temper tire is installed It is necessary to set a difference in the number of teeth for forcibly giving a difference in rotation to the front and rear wheels while considering various conditions such as passenger cars, trucks, or 4WD for the front wheel drive base or 4WD for the rear wheel drive base. It is necessary to uniquely set the difference in the number of teeth according to the above.
[0008]
In addition, when driving on a slippery slope, the diff-lock is not performed until the wheel has made a predetermined slip, so the rear wheel may flow sideways or the vehicle body may cause a so-called tail swing, which may significantly reduce the traveling performance. .
[0009]
Further, when turning, the diff lock is not performed unless the rotation difference between the front and rear wheels slips by a rotation difference due to a preset turning radius. Therefore, if the center differential is in the free state and the rear wheels do not slip, the diff lock, that is, the direct connection 4WD, will not be achieved, especially when applied to motor sports, the running performance will be reduced, or depending on the accelerator work Inconveniences such as inability to obtain smooth turning performance (turning performance) and steering stability occur.
[0010]
Further, during reverse travel (during reverse travel), the one-way clutch is locked and becomes directly connected 4WD, so that the tight corner braking phenomenon is prevented by weakening the operating pressure of the hydraulic clutch during turning. For this reason, there is a possibility that sufficient traction cannot be obtained at the time of towing or traveling at a high load.
[0011]
Next, in the technique of the power distribution device in which the forward and reverse one-way clutches are arranged on the bevel gear shaft of the transfer, the effective radius of the tire is the same as the technique described in the above-mentioned Japanese Patent Publication No. 48-3971. Depending on the weight distribution and the like, internal circulation torque is generated in the drive system of the front wheels and the rear wheels during straight running, which may cause deterioration in transmission efficiency and fuel efficiency.
[0012]
In addition, when applied to motor sports or the like, there is an inconvenience that the turning ability at the time of turning is not preferable and the cause of turning cannot be grasped at the corner-in.
[0013]
Next, in the technology described in Japanese Utility Model Laid-Open No. 61-81428, when a difference in rotation occurs between the front wheels and the rear wheels during 4WD traveling, a mechanism is automatically switched to two-wheel drive by a one-way clutch. Therefore, depending on the case, a decrease in running performance, lack of traction, etc. may occur.
[0014]
Also, during straight running, as in the above-mentioned technologies, internal circulation torque is generated between the front and rear wheels depending on variations in the effective tire radius, tire air pressure, weight distribution, etc., which causes a reduction in transmission efficiency and fuel consumption. It becomes.
[0015]
Next, even in the technique described in Japanese Patent Application Laid-Open No. 3-217333, when the relationship between the front and rear wheel rotation difference is the front wheel <rear wheel due to a difference in the effective radius of the front and rear tires, the one-way clutch is always directly connected. As in the above-described technologies, internal circulation torque is generated between the front and rear wheels, which causes a reduction in transmission efficiency and fuel consumption.
[0016]
Further, if the tires are continuously run when the tires have significantly different air pressures, or when front wheels and rear wheels having different effective radii are erroneously mounted, there is a risk of damage to drive system members such as hypoid gears.
[0017]
Furthermore, since the one-way clutch is engaged when reversing, a tight corner braking phenomenon occurs due to a difference in turning radius between the front and rear wheels when turning.
[0018]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lightweight and compact four-wheel drive device for a vehicle that has a turning performance suitable for sports driving, and has high transmission efficiency and traction performance. .
[0019]
[Means for Solving the Problems]
In order to solve the above-described problem, a vehicle four-wheel drive device according to a first invention includes a power distribution device capable of distributing power output from an output shaft of a transmission mechanism to a front wheel drive system and a rear wheel drive system, A vehicle four-wheel drive device comprising: a power distribution control device that controls the power distribution device, wherein the power distribution device is provided on the output shaft, and the front wheel drive system And above A first clutch that is freely engageable with the output shaft, and the output shaft; Above rear wheel The rotational speed of the drive system is front wheel Through a one-way clutch that can transmit power only when the rotational speed of the drive system is greater than the above, front wheel A second clutch capable of engaging the drive system and the output shaft, and the output shaft and the output clutch. Rear wheel The power distribution control device variably controls the engagement of the first clutch and the second clutch according to at least the running state of the vehicle and the road surface condition. And
[0020]
According to a second aspect of the present invention, there is provided the vehicle four-wheel drive device according to the first aspect, wherein the power distribution control device includes at least a front wheel rotation speed, a rear wheel rotation speed, an engine output, and a gear of a transmission mechanism. The engagement of the first clutch and the second clutch is variably controlled based on the position and the turning amount.
[0021]
According to a third aspect of the present invention, there is provided the four-wheel drive device for a vehicle according to the first or second aspect, wherein the power distribution control device is configured to travel forward in an appropriate state at least within a preset range of each wheel. In some cases, the second clutch is controlled to be engaged, and the first clutch is controlled to be engaged as necessary.
[0022]
According to a fourth aspect of the present invention, there is provided the vehicle four-wheel drive device according to any one of the first to third aspects, wherein the power distribution control device controls the release of the second clutch during reverse travel. The first clutch is slip-controlled as necessary.
[0023]
According to a fifth aspect of the present invention, there is provided the vehicle four-wheel drive device according to any one of the first to fourth aspects, wherein the power distribution control device is configured such that each wheel is out of a preset range. The second clutch is controlled to be released, and the first clutch is controlled to slip as necessary.
[0024]
According to a sixth aspect of the present invention, in the vehicle four-wheel drive apparatus according to any one of the first to fifth aspects, the first clutch and the second clutch are arranged in the same clutch drum. A hydraulic multi-plate clutch, wherein the first clutch is disposed on one end side in the clutch drum, and the second clutch is on the other end of the first clutch in the same clutch drum. Further, a first piston corresponding to the first clutch is disposed on the other end side in the clutch drum, and the first piston is disposed between the clutch drum and the first piston. Forming a first hydraulic chamber for operating the piston, and disposing a second piston corresponding to the second clutch closer to one end than the first piston in the clutch drum. A second hydraulic chamber for operating the second piston is formed between the first piston and the second piston, and the operation of the first piston is transmitted to the first clutch. A pressure pin for passing through a driven plate and a retaining plate constituting the second clutch and facing the first clutch, and transmitting the operation of the second piston to the second clutch. The pressure pin faces the second clutch.
[0025]
According to a seventh aspect of the present invention, there is provided the vehicle four-wheel drive apparatus according to any one of the first to sixth aspects, wherein the final reduction ratio of the front wheel drive system and the final reduction ratio of the rear wheel drive system are set to different gear ratios. In addition, the vehicle is characterized in that the front wheel rotational speed is set to be larger than the rear wheel rotational speed during straight traveling.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a plan view showing an outline of a four-wheel drive device for a vehicle, FIG. 2 is a skeleton diagram showing the main part of a manual transmission for a four-wheel drive vehicle, and FIG. FIG. 4 is a cross-sectional view of the main part of the power distribution device, FIG. 5 is a cross-sectional view of the main part of the one-way clutch, and FIG. 6 is an overall schematic configuration of the vehicle four-wheel drive device. FIG. 7 is a diagram illustrating the configuration of the hydraulic control device, and FIG. 8 is a chart illustrating the state of the clutch in a typical traveling state.
[0027]
The drive train of the four-wheel drive device for a vehicle will be described. As shown in an arrangement plan view in FIG. 1 (a), the manual transmission 1 for a four-wheel drive vehicle is installed in an engine 10 that is arranged vertically in front of the vehicle. It is integrally joined to transmit power to the front wheel 3 and transmit power to the rear wheel 6 via the propeller shaft 4 and the rear differential device 5 or the like, or as shown in FIG. The manual transmission 1 is joined to an engine 10 that is vertically disposed to transmit power to the rear wheel 6 and transmit power to the front wheel 3 via the propeller shaft 4 and the front differential device 7.
[0028]
Here, in the present embodiment, the former is a case where the manual transmission 1 is arranged together with the engine 10 in front of the vehicle, and the final reduction ratio of the final gear on the front wheel 3 side and the final gear on the rear wheel 6 side are set. A case where the final reduction ratio is equal and the effective radii of the front and rear wheels are equal will be described as an example.
[0029]
Referring to FIG. 2, the manual transmission 1 will be described. Reference numeral 10 denotes a vertical engine, a clutch case 12 which is joined to the vertical engine 10 and accommodates the clutch 20, and one drive system behind the clutch case 12. The differential housing 13 that houses the front differential device 30 that constitutes the vehicle, the main case 14 that houses the manual transmission gear mechanism 40 behind the differential housing 13, and the extension that is located behind the main case 14 and houses the power distribution device 50. Cases 15 are sequentially joined to form a transmission case 16.
[0030]
The crankshaft 11 of the vertical engine 10 is connected to the clutch 20 inside the clutch case 12, and the input shaft 21 connected to the clutch 20 is connected to the output shaft 41 and the counter shaft 42 of the manual transmission gear mechanism 40 inside the main case 14. The power from 11 is transmitted.
[0031]
Then, the power shifted by the manual transmission gear mechanism 40 is output to the output shaft 41 arranged coaxially with the input shaft 21, and the output from the output shaft 41 is input to the power distribution device 50 inside the extension case 15 to distribute the power. The device 50 is configured to be transmitted to the front wheel 3 via the front differential device 30, and is configured to be transmitted to the rear wheel 6 via the propeller shaft 4 and the rear differential device 5 constituting the other drive system.
[0032]
The clutch 20 is a flywheel 22 that is integrally coupled to the crankshaft 11 of the engine 10, a clutch cover 23 that is integrally coupled to the flywheel 22, and rotates together with these to freely move along the input shaft 21. A driving side composed of a pressure plate 24 and a driven side of a clutch disk 25 which is slidably fitted to the input shaft 21 between the pressure plate 24 and the pressure plate 24 always causes the clutch disk 25 to fly to the flywheel 22 by a spring force. The rotational force from the crankshaft 11 is transmitted to the input shaft 21 by the friction force.
[0033]
The clutch 20 is disengaged by pushing the release bearing 27 with a release fork (not shown) and separating the pressure plate 24 from the flywheel 22.
[0034]
The input shaft 21 is rotatably supported by the main case 14 at the front end of the flywheel 22 via a pilot bearing and the rear portion of the input shaft 21 via a bearing, and manually shifts with an input drive gear 29 provided at the rear end of the input shaft 21. The manual transmission gear mechanism 40 is transmitted from the input shaft 21 by meshing with a counter driven gear 43 provided at the front end of the counter shaft 42 of the gear mechanism 40.
[0035]
The manual transmission gear mechanism 40 has an output shaft 41 whose front end is rotatably supported by the rear end of the input shaft 21 and whose rear end is rotatably supported by the main case 14 on the same axis as the input shaft 21, and an output. The counter shaft 42 is disposed below the shaft 41 and in parallel with the output shaft 41. The counter shaft 42 is rotatably supported by the main case 14 at the front end and the rear end via bearings.
[0036]
The counter shaft 42 has a hollow shape penetrating along the axis of the counter shaft 42. The third speed drive gear 44c, the second speed drive gear 44b, the first speed drive gear 44a and the reverse drive gear 44f are integrally formed in this order from the counter driven gear 43 side. Further, a 5-speed drive gear 44e is spline-fitted behind the reverse drive gear 44f.
[0037]
On the other hand, the output shaft 41 has a third speed driven gear 45c, a second speed driven gear 45b, a first speed driven gear 45a, and a third speed driven gear 45b. A 5-speed driven gear 45e is rotatably mounted via a 2-dle bearing, and a reverse-driven gear 45f is rotatably mounted via a needle bearing between the 1-speed driven gear 45a and the 5-speed driven gear 45e. .
[0038]
Here, each drive gear provided on the counter shaft 42 is formed with a gradually increasing diameter in the order of the first speed drive gear 44a, the second speed drive gear 44b, the third speed drive gear 44c, and the fifth speed drive gear 44e. The provided driven gears are formed so as to gradually increase in diameter in the order of the fifth speed driven gear 45e, the third speed driven gear 45c, the second speed driven gear 45b, and the first speed driven gear 45a.
[0039]
The reverse drive gear 44f meshes with a reverse idler gear 46f rotatably supported by an idler shaft 46 disposed between a wall portion provided in the main case 14 and a bearing portion, and the reverse idler gear 46f is an output. The reverse drive gear 45f disposed on the shaft 41 is engaged with the reverse drive gear 44f, and the reverse drive gear 44f and the reverse drive gear 45f are interlocked in the same rotation direction.
[0040]
Between the second-speed driven gear 45b and the first-speed driven gear 45a on the output shaft 41, the first-speed driven gear 45a and the second-speed driven gear 45b that are rotatably supported by the output shaft 41 are selectively driven by the output shaft 41. A first synchronizer 47 for 1st and 2nd speeds connected so as to be able to transmit is arranged.
[0041]
Then, after the first-speed driven gear 45a is synchronized with the rotation of the output shaft 41 via the first synchronizer 47 by moving the sleeve backward from the neutral state by the selector, the input shaft is connected to the output shaft 41 so that power can be transmitted. The power input from 21 to the counter shaft 42 via the input drive gear 29 and the counter driven gear 43 is decelerated corresponding to the first gear according to the number of teeth of the first speed drive gear 44a and the first speed driven gear 45a and is output to the output shaft 41. Or, conversely, the output shaft 41 is configured to be transmitted to the input shaft 21 via the counter shaft 42, the counter driven gear 43, and the input drive gear 29 via the first speed driven gear 45a and the first speed drive gear 44a. Further, by returning to the neutral state, the connection between the output shaft 41 and the first speed driven gear 45a is released. On the other hand, the second-speed driven gear 45b is synchronized with the counter shaft 42 by moving the sleeve of the first synchronizer 47 forward, and then connected to the output shaft 41 to correspond to the number of teeth of the second-speed drive gear 44b and the second-speed driven gear 45b. 2nd speed is obtained.
[0042]
Between the input drive gear 29 provided at the rear end of the input shaft 21 and the third speed driven gear 45c, a second synchronizer 48 for the third and fourth speeds is interposed, and the sleeve of the second synchronizer 48 is moved backward. The third speed driven gear 45c is synchronized with the rotation of the output shaft 41 by being moved to, and then connected to the output shaft 41 so as to be able to transmit power to the third speed drive gear 44c and the third speed gear corresponding to the number of teeth of the third speed driven gear 45c. Is obtained. On the other hand, after the rotation of the input shaft 21 and the output shaft 41 is synchronized by moving the sleeve of the second synchronizer 48 forward, the input shaft 21 and the output shaft 41 are connected so as to be able to transmit power and the input shaft 21 and the output shaft are connected. The fourth speed stage is obtained by functioning as a direct connection stage meshing mechanism in which 41 is in a directly connected state.
[0043]
Further, a third synchronizer 49 is interposed between the reverse driven gear 45f and the fifth speed driven gear 45e. By moving the sleeve of the third synchronizer 49 rearward, the fifth speed driven gear 45e rotates the output shaft 41. Are synchronized with the output shaft 41 so that power can be transmitted, and a fifth gear corresponding to the number of teeth of the fifth gear drive gear 44e and the fifth gear driven gear 45e is obtained. On the other hand, the reverse driven gear 45f is synchronized with the rotation of the output shaft 41 by moving the sleeve of the third synchronizer 49 forward, and then connected to the output shaft 41 so that power can be transmitted, so that the reverse driven gear 45f and the reverse driven gear 45f are reverse A reverse gear that meshes so that power can be transmitted via the idler gear 46f is obtained.
[0044]
A front drive shaft 31 passes through the counter shaft 42 formed in a hollow shape, and a front end of the front drive shaft 31 is formed with a pinion portion 31a that always meshes with a final gear of the front differential device 30, for example, a hypoid gear 32. The part is provided with a taper bearing, and the rear end part is rotatably supported by the front end and the rear end of the main case 14 via a bearing.
[0045]
Next, a power distribution device 50 in the rear portion of the transmission case 16, that is, in the extension case 15, includes an output shaft 41 extended into the extension case 15, and a clutch drum 51 that is rotatable coaxially with the output shaft 41. The first clutch 52 disposed inside the clutch drum 51 and capable of freely engaging the output shaft 41 and the clutch drum 51, the one-way clutch 53 provided on the output shaft 41, and the first inside the clutch drum 51 The second clutch 54 is provided so as to be capable of engaging with the clutch drum 51 and the one-way clutch 53.
[0046]
The output shaft 41 is connected to the propeller shaft 4 outside the extension case 15 and transmits power to the rear wheels 6 and 6 via the propeller shaft 4 and the rear differential device 5.
[0047]
Further, the clutch drum 51 is provided with a transfer drive gear 51a, and this transfer drive gear 51a is always meshed with a transfer driven gear 31b provided on the front drive shaft 31. When at least one of the first and second clutches 52 and 54 is engaged and the power is distributed from the output shaft 41 to the clutch drum 51, the power distributed to the clutch drum 51 is the front drive. It is transmitted to the front wheels 3 and 3 via the shaft 31 and the front differential device 7.
[0048]
Here, when the second clutch 54 is engaged, the one-way clutch 53 is locked when the rotation speed of the output shaft 41 is larger than the rotation speed of the clutch drum 51, and the power of the output shaft 41 is transferred to the clutch drum 51. When the rotation speed of the output shaft 41 is smaller than the rotation speed of the clutch drum 51, the transmission is free.
[0049]
Next, the mechanism of the power distribution device 50 will be described in detail.
As shown in FIG. 4, the first clutch 52 is disposed rearward (toward the right in the figure) in the clutch drum 51, and a plurality of drive plates 60 and a plurality of driven plates 61 are alternately stacked. Further, a retaining plate 62 having substantially the same radial shape as the driven plate 61 is disposed on the rear end so as to constitute a main part.
[0050]
More specifically, the first clutch hub 63 is fixed to the outer periphery of the output shaft 41, and the drive plate 60 is supported by the inner periphery being splined to the outer periphery of the first clutch hub 63. .
[0051]
Further, the driven plate 61 and the retaining plate 62 are supported by the outer periphery being splined to the inner periphery of the clutch drum 51.
[0052]
A snap ring 64 is provided on the inner periphery of the clutch drum 51, and the retaining plate 62 is engaged with the snap ring 64, so that the plates constituting the first clutch 52 are moved rearward. Movement is regulated.
[0053]
The second clutch 54 is disposed closer to the front (leftward in FIG. 4) than the first clutch 52 in the clutch drum 51, and includes a plurality of drive plates 65, a plurality of driven plates 66, and the like. Are arranged in an overlapping manner, and a retaining plate 67 having a radial shape substantially the same as that of the driven plate 66 is arranged on the rear end to constitute a main part.
[0054]
More specifically, a second clutch hub 68 is provided on the outer periphery of the output shaft 41 via the one-way clutch 53, and the drive plate 65 has an inner periphery on the outer periphery of the second clutch hub 68. Supported by spline connection.
[0055]
Further, the driven plate 66 and the retaining plate 67 are supported by the outer periphery being splined to the inner periphery of the clutch drum 51.
[0056]
As shown in FIG. 5, the one-way clutch 53 includes a plurality of sprags 53a arranged in a space between an output shaft 41 as an inner race and a second clutch hub 68 as an outer race. The sprag 53a locks when the rotational speed of the output shaft 41 is larger than the rotational speed of the second clutch hub 68, and becomes free when the rotational speed of the output shaft 41 is smaller than the rotational speed of the second clutch hub 68. Is.
[0057]
A bearing 53b is provided on the side surface of the one-way clutch 53, and the distance between the output shaft 41 and the second clutch hub 68 is kept constant by the bearing 53b.
[0058]
Here, the first and second clutches 52 and 54 are hydraulic multi-plate clutches in the present embodiment. Therefore, the power distribution device 50 is further disposed closer to the inside front of the clutch drum 51 than the first clutch 52 and 54. A first piston 70 that operates one clutch 52 and a second piston 71 that operates a second clutch 54 are provided.
[0059]
More specifically, a cylindrical bearing 51b for pivotally supporting the output shaft 41 is formed at a position near the front of the clutch drum 51 so as to protrude rearward. The inner edge portion is slidably fitted to the outer periphery of the bearing portion 51b via the seal ring, and the outer edge portion is slidably fitted to the inner circumference of the clutch drum 51 via the seal ring.
[0060]
The first piston 70 is integrally formed with a ring member 70a protruding rearward along the outer edge, and a plurality of (for example, four) the first clutch 52 can be pressed at the end of the ring member 70a. The pressure ring 72 provided with the pressure pins 72a at equal positions is connected in a freely rotatable manner via a bearing.
[0061]
Here, the driven plate 66 and the retaining plate 67 are provided with spline notches (not shown) corresponding to the pressure pins 72a at equal positions along the outer periphery, and the pressure pins 72a are connected to the splines. The first clutch 52 is pressed through the notch.
[0062]
Further, a snap ring 73 is provided near the tip of the pressure pin 72a, and a retaining plate 67 is engaged with the snap ring 73, whereby the plates constituting the second clutch 54 are moved rearward. Movement is regulated.
[0063]
The second piston 71 is slidably fitted to the outer periphery of the bearing portion 51b via the seal ring at the rear of the first piston 70, and the outer edge portion is interposed via the seal ring. And is slidably fitted to the inner periphery of the ring member 70a.
[0064]
A pressure ring 74 having a plurality of (for example, four) pressure pins 74a that can press the second clutch 54 at equal positions is connected to the second piston 71 via a bearing so as to be relatively rotatable. Has been.
[0065]
Reference numeral 75 in the drawing denotes a return spring, and the first and second pistons 70 and 71 are urged forward by the return spring 75.
[0066]
A first hydraulic chamber 76 is formed between the clutch drum 51 and the first piston 70, and a second hydraulic chamber 77 is formed between the first piston 70 and the second piston 71. Is formed.
[0067]
A first hydraulic pressure supply path 78 and a second hydraulic pressure supply path 79 are communicated with the first hydraulic chamber 76 and the second hydraulic chamber 77, respectively. The hydraulic pressure is supplied to each hydraulic chamber.
[0068]
Next, the hydraulic control device 80 for supplying hydraulic pressure to the hydraulic chambers 76 and 77 will be described with reference to FIG. The supply system of the control hydraulic pressure to the first and second hydraulic chambers 76 and 77 is substantially the same. Therefore, hereinafter, the control hydraulic pressure is supplied to the first hydraulic chamber 76 through the first hydraulic supply path 78. Only the hydraulic pressure supply system will be described.
[0069]
The discharge pressure of the oil pump 83 driven by the motor 82 is regulated by the regulator valve 84 to generate a predetermined hydraulic oil and hydraulic pressure, and the hydraulic pressure oil path 85 includes the clutch control valve 86 and the first hydraulic pressure supply path. The first hydraulic chamber 76 communicates with the first hydraulic chamber 76 through 78.
[0070]
The oil passage 85 is connected to the control side of the duty solenoid valve 89 and the clutch control valve 86 by a pilot valve 87 and an oil passage 88.
[0071]
Then, a duty signal from a power distribution control device 90 to be described later is input to the duty solenoid valve 89, and a predetermined duty pressure corresponding to the duty ratio is generated by the duty solenoid valve 89, and the clutch control valve 86 is generated by this duty pressure. Is operated, the clutch hydraulic pressure supplied to the first hydraulic chamber 76 is controlled, and the first clutch 52 constituted by a hydraulic multi-plate clutch is operated.
[0072]
The control hydraulic pressure supply system to the second hydraulic chamber 77 is configured similarly.
[0073]
The power distribution control device 90 is composed of a microcomputer or the like, and as shown in FIG. 6, at least a front wheel rotational speed sensor 91, a rear wheel rotational speed sensor 92, a throttle opening sensor 93, and a turning angle sensor 94. Based on inputs from the engine rotation speed sensor 95, the gear position sensor 96, etc., the running state and road surface condition are detected, and the control oil pressure to the first and second clutches 52, 54 is set, for example, in a preset map. And the like for each gear position and output to each solenoid valve of the hydraulic control device 80.
[0074]
Here, the front wheel rotational speed sensor 91 detects the front wheel rotational speed from, for example, a speedometer gear (not shown) provided in the front differential device 30, and the rear wheel rotational speed sensor 92 includes, for example, the extension case 15. The rear wheel rotational speed is detected from the rotational speed of the output shaft 41.
[0075]
A throttle opening sensor 93 and an engine rotation speed sensor 95 are provided in the engine 10 and detect an output signal from the engine based on these.
[0076]
The turning angle sensor 94 is provided in the steering to detect the turning amount.
[0077]
The gear position sensor 96 is provided in a gear shaft system (not shown) of the manual transmission gear mechanism 40, or the position of the traveling gear position is obtained by calculation using an existing sensor. .
[0078]
In the power distribution device 50 of the vehicle four-wheel drive device configured as described above, the engaging operations of the first and second clutches 52 and 54 are performed as follows.
[0079]
First, based on a signal from the power distribution control device 90, when the hydraulic pressure is supplied only from the hydraulic control device 80 to the first hydraulic chamber 76, the first piston 70 is moved rearward by this hydraulic pressure, and the pressure is increased. The first clutch 52 is pressed through the pin 72a. At this time, the second piston 71 is also pressed by the first piston 70 and moves rearward. However, since the pressure pin 74a and the snap ring 73 move at an equal pitch, the second clutch 54 is not engaged. It is moved backwards as it is. Therefore, when the operating hydraulic pressure is supplied only to the first hydraulic chamber 76, only the first clutch is engaged.
[0080]
Next, based on a signal from the power distribution control device 90, when the hydraulic pressure is supplied only from the hydraulic control device 80 to the second hydraulic chamber 77, the second piston 71 is moved backward by this hydraulic pressure, The second clutch 54 is pressed through the pressure pin 74a. As a result, when the hydraulic pressure is supplied only to the second hydraulic chamber 77, only the second clutch 54 is engaged.
[0081]
Next, when operating hydraulic pressure is supplied from the hydraulic control device 80 to the first hydraulic chamber 76 and the second hydraulic chamber 77 based on a signal from the power distribution control device 90, the hydraulic pressure is supplied to the first hydraulic chamber 76. Due to the operating hydraulic pressure, the first piston 70 is moved rearward to press the first clutch 52 via the pressure pin 72 a and the second piston 71 is moved rearward to be supplied to the second hydraulic chamber 77. The second piston 71 is further moved rearward by the actuated hydraulic pressure and presses the second clutch 54 via the pressure pin 74a. As a result, when the hydraulic pressure is supplied to the first and second hydraulic chambers 76 and 77, the first and second clutches 52 and 54 are both engaged.
[0082]
Here, as described above, the second piston 71 is moved rearward together with the first piston 70 when the first piston 70 is moved rearward. Is not affected by the behavior of the first piston 70.
[0083]
Therefore, the second clutch 54 configured as described above is not affected by the centrifugal hydraulic pressure applied to the hydraulic oil in the first hydraulic chamber 76 even when the clutch drum 51 is rotated. The influence of the centrifugal hydraulic pressure during the rotation of 51 can be minimized, and the operation accuracy can be maintained at a high level.
[0084]
Next, the operation of the power distribution device 50 configured as described above in a typical traveling state will be described with reference to FIG.
[0085]
First, during forward travel, the power distribution control device 90 normally performs control to release the first clutch 52 and engage the second clutch 54.
[0086]
In such a state, the one-way clutch 53 is locked due to its characteristics, for example, during acceleration running when the accelerator is turned on.
[0087]
Therefore, the power output from the manual transmission gear mechanism 40 via the output shaft 41 is transmitted to the rear differential device 5 via the propeller shaft 4 connected to the output shaft 41, and the one-way clutch 53, the second Power is distributed from the output shaft 41 via the clutch 54 and the clutch drum 51 and transmitted to the front differential device 30.
[0088]
That is, during forward travel with the accelerator turned on, the power distribution device 50 basically functions as a direct-coupled 4WD with the second clutch 54 engaged and the one-way clutch 53 locked, and the output shaft 41 The power output via is distributed to the front and rear wheels.
[0089]
By the way, when a difference occurs in the effective radii of the front and rear wheels, internal circulation torque is generated in the front and rear drive systems, and the power of the engine 10 is not effectively transmitted to each wheel, which adversely affects power transmission efficiency and fuel consumption. There is. In such a case, the power distribution control device 90 performs slip control on the engagement of the second clutch 54 as necessary based on the input of each sensor while the first clutch 52 is released.
[0090]
On the other hand, the one-way clutch 53 is in a free state due to its characteristics, for example, during coasting coasting when the accelerator is turned off or when the brake is operated.
[0091]
Accordingly, the power output from the manual transmission gear mechanism 40 via the output shaft 41 is transmitted only to the rear differential device 5 via the propeller shaft 4 connected to the output shaft 41.
[0092]
That is, during forward travel when the accelerator is turned off, the power distribution device 50 basically functions as FR, and the power output via the output shaft 41 is transmitted to the rear wheels 6 and 6.
[0093]
By the way, when traveling on a downhill with the accelerator off, the one-way clutch 53 is free and the power distribution device 50 functions as an FR, so that the vehicle behavior may not be preferable. This is particularly noticeable when the vehicle travels downhill on a slippery road surface. In such a case, the power distribution control device 90 engages the first clutch 52 as necessary based on the input of each sensor. The front and rear drive systems are placed in a restrained state to stabilize the vehicle behavior.
[0094]
Next, during turning traveling during forward traveling, the power distribution control device 90 performs control so that the first clutch 52 is released and the second clutch 54 is engaged.
[0095]
During this turning, if the front wheels 3 and 3 rotate fast due to the difference in turning radius with the rear wheels 6 and 6, the one-way clutch 53 becomes free and the power distribution device 50 functions as FR. When all the power is transmitted to the rear wheels 6 and 6, each wheel often slips, but the slip amount of the rear wheels 6 and 6 to which power transmission is performed is the slip amount of the front wheels 3 and 3. When the number is larger, the one-way clutch 53 is automatically engaged, and the power transmission device 50 functions as the direct connection 4WD.
[0096]
Therefore, the power transmission device 50 becomes an FR in which the one-way clutch 53 becomes free at the initial stage of turning and becomes the turning cause, and then becomes a direct connection 4WD. Sometimes it shows good turning performance.
[0097]
Next, during reverse travel, the power distribution control device 90 controls to release the second clutch 54 and performs slip control of the first clutch 52 in accordance with the input of each sensor. Here, the slip control of the first clutch 52 by the power distribution control device 90 is performed according to the input of each sensor, and the degree of engagement is strengthened when going straight and the degree of engagement is eased when turning. is there.
[0098]
By releasing the second clutch 54 and controlling the slip of the first clutch 52 in this way, it is possible to avoid the occurrence of a tight corner braking phenomenon when the one-way clutch 53 is locked during reverse running and the vehicle is turning backward. it can.
[0099]
If both the first and second clutches 52 and 54 are released, the power distribution device 50 enters the FR state, but may be controlled to this state when the road surface friction coefficient is high.
[0100]
Next, when the difference between the effective radii of the front and rear wheels becomes larger than a preset range due to a decrease in tire air pressure or the like, the power distribution control device 90 responds to the input of each sensor and the second clutch 54. Is released, and the first clutch 52 is slip-controlled as necessary.
[0101]
In other words, the direct connection 4WD improves the running performance when traveling on rough roads, but the internal radius is increased when there is a large difference in the effective radius of the front and rear wheels when traveling on a paved road surface or the like with a high coefficient of friction. Since circulation torque is generated and adversely affects transmission efficiency and fuel consumption, the second clutch 54 is controlled to be released, and the first clutch 52 is controlled to slip as necessary to avoid the above problem.
[0102]
Thus, the vehicle four-wheel drive device according to the present embodiment is configured so that power can be transmitted by directly connecting the output shaft 41 to the rear wheel 6 side, and the first clutch 52 or the one-way clutch is provided on the front wheel 3 side. Since the power can be distributed via the 53 and the second clutch 54, the structure can be simplified, and the light and compact power distribution device 50 can be provided.
[0103]
Furthermore, the power distribution device 50 of the above-described four-wheel drive system for a vehicle is configured by arranging a first clutch 52, a one-way clutch 53, and a second clutch 54 in a single clutch drum 51. The structure can be simplified, and a light and compact power distribution device 50 can be provided.
[0104]
Further, the power distribution device 50 of the vehicle four-wheel drive device makes the first clutch 52 disengaged and the second clutch 54 engaged when turning, and the one-way clutch 53 acts to turn. Since it functions as 4WD after functioning as FR at the beginning of time, it is possible to remarkably improve the turnability.
[0105]
Especially when turning on a slippery road while stepping on the accelerator, it becomes FR at the beginning of turning, and when the rear wheel slips and reaches the same rotation speed as the front wheel, it becomes 4WD instantaneously and the driving force is reliably transmitted to the front and rear wheels. Therefore, a high level of running stability can be obtained.
[0106]
Further, when the second clutch 54 is engaged during forward travel with the accelerator turned on, the one-way clutch 53 is locked due to the characteristics of the one-way clutch 53, and direct-coupled 4WD travel occurs. When this occurs, the power loss can be reduced by controlling the second clutch 54 according to the traveling state, and a full-time 4WD power distribution device with good fuel efficiency can be provided. .
[0107]
Also, during forward travel with the accelerator off, the one-way cook 53 is free due to the characteristics even when the second clutch 54 is engaged, and FR travels. However, depending on the travel state, road surface condition, etc. By engaging the first clutch 52, the power distribution between the front and rear wheels can be controlled to perform 4WD traveling.
[0108]
During reverse travel, the second clutch 54 is released and the first clutch 52 is controlled as necessary to achieve 4WD travel and prevent tight corner braking during turning. can do.
[0109]
In the present embodiment, an example in which the first clutch 52 is configured by a hydraulic multi-plate clutch has been shown. However, the present invention is not limited to this, and the first clutch 52 may be a mechanical clutch, You may comprise a viscous clutch or an electromagnetic clutch.
[0110]
In the present embodiment, an example of a vehicle four-wheel drive device in which the power distribution device 50 is applied to the manual transmission 1 has been shown. However, the present invention is not limited to this, and for example, the power distribution device May be applied to an automatic transmission or a continuously variable transmission to constitute a four-wheel drive device for a vehicle.
[0111]
Further, in the present embodiment, the manual transmission 1 is arranged together with the engine 10 in front of the vehicle, and the final reduction ratio of the final gear on the front wheel 3 side and the final reduction of the final gear on the rear wheel 6 side. The case where the ratio is equal and the effective radii of the front and rear wheels are the same has been described, but the present invention is not limited to this, for example, it is possible to arrange a manual transmission with the engine behind the vehicle, In addition, the final reduction ratios of the front wheel side and the rear wheel side can be set differently in advance, and the effective radii of the front wheel and the rear wheel can be set differently.
[0112]
Here, for example, a predetermined difference is provided in advance between the final reduction ratio on the front wheel side and the final reduction ratio on the rear wheel side, and the rotational speed of the wheel always maintains the relationship of front wheel> rear wheel when traveling straight ahead. By configuring the drive train in this way, it is possible to provide a vehicle four-wheel drive device that can reliably exhibit the above-described 4WD function in consideration of variations in tire diameter.
[0113]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the power distribution device 50 is configured by the first clutch 52 and the second clutch 54 via the one-way clutch 53, the lightweight and compact vehicle 4 A wheel drive device can be provided.
[0114]
According to the invention described in claim 2, the first clutch 52 and the second clutch 54 are controlled by the power distribution control device according to each driving situation and road surface condition, thereby achieving the effect of the invention described in claim 1. In addition, it has turning performance suitable for sports driving, and can maintain high transmission efficiency and traction performance.
[0115]
According to the invention of claim 3, in addition to the effects of the inventions of claims 1 and 2, when traveling on a slippery downhill road, the first clutch is engaged as necessary to directly connect 4WD. By doing so, the vehicle behavior can be stabilized.
[0116]
According to the fourth aspect of the invention, in addition to the effects of the first to third aspects of the invention, the second clutch is released during reverse running, and the first clutch is slip-controlled as necessary. Thus, it is possible to avoid the occurrence of a tight corner braking phenomenon during reverse turning.
[0117]
According to the invention described in claim 5, in addition to the effects of the invention described in claims 1 to 4, when a large difference occurs in the effective radii of the front and rear wheels when traveling on a paved road surface or the like having a high friction coefficient, The release control of the second clutch and the slip control of the first clutch can prevent the internal circulation torque from being generated and adversely affecting the transmission efficiency and fuel consumption.
[0118]
According to the invention described in claim 6, in addition to the effects of the invention described in claims 1 to 5, the structure can be simplified, and a light and compact power distribution device can be provided.
[0119]
According to the seventh aspect of the present invention, since the front wheel rotational speed is set to be larger than the rear wheel rotational speed during straight traveling, the first to sixth aspects are surely considered in consideration of variations in the tire diameter. The effects of the described invention can be exhibited.
[Brief description of the drawings]
FIG. 1 is a plan view showing an outline of a four-wheel drive device for a vehicle.
FIG. 2 is a skeleton diagram showing the main part of a manual transmission for a four-wheel drive vehicle.
FIG. 3 is a skeleton diagram showing the main part of the power distribution device.
FIG. 4 is a cross-sectional view of the main part of the power distribution device.
FIG. 5 is a cross-sectional view of the main part of a one-way clutch.
FIG. 6 is an explanatory diagram showing an overall schematic configuration of a four-wheel drive device for a vehicle.
FIG. 7 is a configuration diagram of a hydraulic control device.
FIG. 8 is a chart showing clutch states in typical driving states.
[Explanation of symbols]
3 ... front wheel
4 ... Propeller shaft (the other drive system)
5 ... Rear differential device (the other drive system)
6 ... Rear wheel
7 ... Front differential device (One drive system)
41… Output shaft
42 ... Counter shaft (the other drive system)
50 ... Power distribution device
52 ... 1st clutch
53… One-way clutch
54 ... Second clutch
90 ... Power distribution control device
91 ... Front wheel rotational speed sensor
92 ... Rear wheel rotational speed sensor
93 ... Throttle opening sensor
94 ... Steering angle sensor
95… Engine speed sensor
96 ... Gear position sensor

Claims (7)

A power distribution device capable of distributing power output from the output shaft of the speed change mechanism to the front wheel drive system and the rear wheel drive system;
A power distribution control device for controlling the power distribution device, and a vehicle four-wheel drive device comprising:
The power distribution device is
Provided on the output shaft, a first clutch freely engaging the said front wheel drive system and the upper SL output shaft,
Provided on the output shaft, the rotational speed of the rear wheel drive system through a one-way clutch which can only power transmission is greater than the rotational speed of the front wheel drive system, engaging the said front wheel drive system and the output shaft A free second clutch, and
The output shaft and the rear wheel drive system are directly connected and configured,
4. The vehicle four-wheel drive device according to claim 1, wherein the power distribution control device variably controls the engagement of the first clutch and the second clutch according to at least a running state and a road surface condition of the vehicle.   The power distribution control device includes the first clutch and the second clutch based on at least the front wheel rotation speed, the rear wheel rotation speed, the engine output, the gear position of the speed change mechanism, and the turning amount. The four-wheel drive device for a vehicle according to claim 1, wherein engagement of the clutch is variably controlled.   The power distribution control device controls the engagement of the second clutch and engages the first clutch as necessary at least during forward traveling in a proper state within a predetermined range of each wheel. The four-wheel drive system for a vehicle according to claim 1 or 2, characterized by performing joint control.   The power distribution control device according to any one of claims 1 to 3, wherein when the vehicle is traveling backward, the second clutch is controlled to be released and the first clutch is controlled to slip when necessary. The four-wheel drive device for vehicles described in 2.   The power distribution control device performs release control of the second clutch and slip control of the first clutch as necessary when each wheel is out of a preset range. The vehicle four-wheel drive device according to any one of claims 1 to 4.   The first clutch and the second clutch are hydraulic multi-plate clutches arranged continuously in the same clutch drum, and the first clutch is arranged on one end side in the clutch drum. And the second clutch is disposed closer to the other end than the first clutch in the same clutch drum, and the first piston corresponding to the first clutch is disposed at the other end in the clutch drum. A first hydraulic chamber is disposed between the clutch drum and the first piston to actuate the first piston, and a second hydraulic chamber corresponding to the second clutch is formed. A piston is disposed closer to one end than the first piston in the clutch drum, and a second piston is operated between the first piston and the second piston. And a pressure pin for transmitting the operation of the first piston to the first clutch passes through the driven plate and the retaining plate that constitute the second clutch. 6. A pressure pin for causing the clutch to face the clutch and for transmitting the operation of the second piston to the second clutch, wherein the pressure pin faces the second clutch. A four-wheel drive device for a vehicle according to claim 1.   The final reduction ratio of the front wheel drive system and the final reduction ratio of the rear wheel drive system are set to different gear ratios, and the front wheel rotation speed is set to be higher than the rear wheel rotation speed during straight traveling. The four-wheel drive device for vehicles in any one of Claims 1 thru | or 6.

Images