JP2006118572A - Non-slip differential device in linkage with steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-slip differential for eliminating the waste of driving force, improving controllability, fuel consumption, travelling stability and road ability and suppressing the wear of a tire by improving a current non-slip differential which cannot determine slip during turn or during straight run when there is a travel distance difference between right and left driving wheels. <P>SOLUTION: The steering angle of a steering device is linked with the movement of the non-slip differential to automatically determine straight run or turn without giving burden to a driver. Right and left driving wheel axles are connected directly to each other during straight run and mechanical rotating load is applied to a side gear on the turning inside corresponding to the steering angle independently of a road travel resistance difference during turn to properly distribute driving fore to the right and left driving wheel axles. Rotation sensors are mounted on the right and left driving wheel axles for comparing an actual rotating speed ratio between the right and left driving wheel axles with a calculated ideal rotating speed ratio and feedbacking an error to the size of the rotating load to actualize an approximately ideal turning track. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  Non-slip differential

  In an automobile or the like, the driving force is usually distributed to the left and right drive wheels from a single power source through a transmission, a transmission device, etc., and a device called a differential comprising a final reduction gear and a differential gear. The differential gear is a device for adjusting the difference in mileage due to the difference in the turning radius of the drive wheel when the vehicle turns, and the differential gear that drives the four bevel gears in the gear box drives each other. It is the basic type that is attached to the final reduction drive gear rotated by a pinion.

  This type of differential gear will not operate unless the balance of the running resistance of the left and right drive wheels is lost. When the vehicle turns, the driving wheel inside the turn is braked and the running resistance increases, and the driving wheel outside the turning is forcibly rotated to reduce the running resistance. When the difference in running resistance increases, the differential gear works, and the driving force is distributed and moved from the driving wheel with a large running resistance to the driving wheel with a small running resistance.

  When driving on ordinary roads, the driving resistance of the left and right drive wheels is often slightly different. When driving straight or turning, part of the driving force of the left and right wheels is always the one with the higher driving resistance. To drive wheels with low resistance. Not only when going straight, but also when turning, small unnecessary errors in the rotational speed of the left and right drive wheels are generated as slips, affecting power loss, tire wear, and fuel consumption.

  Also, when driving on rough terrain or snowy roads where the driving resistance difference between the left and right driving wheels increases, the driving resistance flows to the driving wheel with the lower resistance, resulting in a further increase in the driving resistance difference between the left and right driving wheels. In some cases, one wheel may run idle and the car may become unable to move. Also, if one drive wheel slips momentarily due to road surface irregularities or dust during high-speed driving, the rotational speed of the idle driving wheel momentarily increases, and when it comes in contact again, a strong driving force is applied and running is not stable. . Various non-slip differentials have been developed and put into practical use as measures to improve these.

  A clutch type that suppresses idle rotation by changing the rotation difference between the left and right drive wheels into a thrust load and mechanically directly connecting and locking the left and right rotation shafts, and generates heat and expands when stirred by the difference in rotation between the left and right drive wheels A viscous coupling body that connects the left and right axles to prevent idle rotation of one wheel. It is mounted on.

  However, most non-slip differentials are post-processing controls that work after a certain amount of differential occurs, and differentials that can mechanically determine the distinction between turning and slip that are originally required for differentials are currently available However, I can hardly find it. If the rotational difference between the left and right drive wheels is limited more than necessary to suppress slipping, the wheels will be locked during turning, resulting in overloading the engine and transmission device, which will cause problems in terms of safe driving and mechanical structure. In addition, non-slip diffs found in the current market tend to be complicated, heavy and expensive, and it is expected that low-price, simple structure, light weight and reliable non-slip diffs will spread.

JP-A-11-348595 Takeshi Hosokawa “Mechanical & Mechanical Picture Book of Cars” Grand Prix Publishing 2003 Shigeru Ito “Dictionary of Mechanisms”

  The two driving states of turning and straight running are determined mechanically and automatically, and the left and right drive wheels are directly connected when going straight, and the left and right drive wheels are brought close to the ideal speed ratio during turning to eliminate unnecessary slip. The purpose is to reduce loss of driving force, improve fuel efficiency, improve running stability, and suppress tire wear.

  A non-slip differential gear is linked to the steering device to automatically determine straight and turning, and the left and right drive wheel shafts are directly connected during straight running, and the differential gear is used regardless of running resistance during turning. A rotational load corresponding to the steering angle of the steering device is given to the side gear inside the turn of the vehicle, and the difference between the actual rotational speed ratio of the left and right drive wheel shafts and the calculated ideal rotational speed ratio of the left and right drive wheel shafts is determined as the rotational load. By feeding back to the size, the error is within the preset allowable range, unnecessary slip is eliminated, and the ideal running state is approached.

  The non-slip differential of the present invention can be expected to improve fuel efficiency, improve running stability, suppress tire wear, etc. by eliminating unnecessary slip. In addition, the turning performance of the automobile can be changed by adjusting the timing and distribution ratio of the driving force during turning to the left and right drive wheels.

  In addition to the use of non-slip differentials for two-wheel drive vehicles and four-wheel drive vehicles, the same effect as four-wheel steering such as anti-phase steering and in-phase steering can be achieved by arbitrarily controlling the distribution of driving force. Expected to improve operability during high-speed driving, parking and turning. In addition, the structure is simple, and we can compete with the current non-slip differentials in terms of weight and price.

The steering angle of the steering device and the rotation of the pinion gear of the differential gear are linked, the rotation of the pinion gear is fixed when going straight, the rotation of the pinion gear is released when turning, and a rotational load corresponding to the steering angle is applied to the side gear inside the turning, Regardless of the difference in running resistance from the road surface, the driving force is mechanically distributed to the side gear outside the turn.
Since the driving wheel travel distance is proportional to the rotational speed of the driving wheel axle, the actual rotational speed ratio of the left and right driving wheel axles is compared with the calculated ideal rotational speed ratio, and the rotation is applied to the side gear inside the turn. By feeding back to the magnitude of the load, it was possible to approach the ideal mileage difference corresponding to the steering angle.

  In ordinary automobiles (four-wheeled vehicles), tires so that all wheels pass on the circumference of concentric and different radii around the turning center O by the Ackermann mechanism so that they can turn without slipping as shown in FIG. Is installed. The distance traveled by the driving wheels of the left and right rear wheels when the vehicle turns is the product of the turning radius and turning angle of the wheel. If the rear wheel is a drive wheel, the travel distance Lo of the turning outer wheel is (= Ro × θ), and the travel distance Li of the turning inner wheel is (= Ri × θ), so the difference in travel distance is Lo-Li = Since (Ro × θ) − (Ri × θ) and the tread width of the left and right drive wheels is TR, Ro = Ri + TR. Therefore, the difference in travel distance between the left and right drive wheels that the differential device should adjust is Lo-Li = TR × θ (tread width × turning angle).

  Here, since the left and right tire diameters are the same, the distance traveled by the wheel is (tire diameter x number of revolutions), and the ratio of the distance traveled by the left and right drive wheels during turning is the ratio of the number of revolutions of the left and right drive wheel axles. The ratio of the travel distance is Lo / Li = (Ro × θ) / (Ri × θ) = 1 + (TR / Ri). If the vehicle travels with the same turning radius, the rotation speed ratio of the left and right drive wheel shafts is constant regardless of the turning angle (θ). When calculating the rotation speed ratio of the left and right drive wheel shafts required for turning in a commercially available small car, the tread width TR (= 1.6 m) of the drive wheel and the turning radius of the turning outer wheel are set to the minimum turning radius Ro (= 4). When turning at .8m), Ri (= 3.2m), the rotation speed ratio of the drive wheel shaft on the outside and inside of the turn is 1.50, and the rotation speed ratio of the drive wheel shaft required for turning is 1.50. Around is expected to be the maximum practical value.

    The non-slip differential of the present invention is a non-circular combination of a semicircular and an elliptical half at the center of the shaft as shown in the explanatory diagram of FIG. A pinion gear (10) without a rotating shaft that freely rotates is attached to both sides of the rotating shaft (12) of the pinion gear that is a non-circular cross-section cam portion (16), and the rotating shaft penetrates the gear portion. The side gear (11) integrated with the shaft is meshed with the left and right. A friction plate (9-1) is attached to the back side of the tooth surface of the pinion gear (10), and the side gear (11) is sandwiched between the gear case (18) on the rotating shaft on the back side of the tooth surface of the side gear (11). A movable brake plate (17) having a friction plate (15-1) that slides on the shaft while meshing with the spline processed portion outside the rotating shaft is incorporated. When the driving force of an automobile is large and it is difficult to fix the pinion gear with a friction plate, a friction plate and a mesh joint are used together.

The control shaft (4) has a rectangular outer shape, and the inside is a circle into which the rotation shaft (12) of the pinion gear is inserted. A friction plate (9-2) is attached to one end of the pipe, and the rotation shaft (12 The flange portion (7) to be combined with the step portion of the rotary shaft (12) of the pinion gear is provided with a straight-turn / swivel switching cam portion (6) for lifting the control shaft (4) in the axial direction when the control shaft is rotated.
A control shaft (4) is put on both sides of the rotation shaft (12) of the pinion gear, and a spring (8) is placed between the gear case (18) and the rear surface of the friction plate (9-2) of the control shaft (4). ) And engage the control shaft (4) in the square mounting holes of the gear case (18).

The length of the rotating shaft extending to the front side of the tooth surface of the side gear (11) is the same as that of the side gear (11 The driving wheel shaft (13) is connected to the rotation shaft on the back side of the tooth surface.
A control lever (5) and an operation lever (14) for rotating the rotating shaft (12) of the pinion gear are provided at both ends of the rotating shaft (12) of the pinion gear which is out of the gear case (18). Install.

  When the vehicle is traveling straight, the friction plate (9-2) of the control shaft (4) mounted in the square mounting hole of the gear case (18) is pressed by the spring (8) and the tooth surface of the pinion gear (10). The rotation of the pinion gear (10) is pressed against the friction plate (9-1) on the back side and the rotation of the left and right side gears (11) is fixed and the driving wheel shaft (13) is forcibly directly connected. The rotation speed is the same. At this time, the rotational position of the rotational shaft (12) of the pinion gear is such that the rotational shaft end surfaces projecting from the left and right side gears (11) at the semicircular portion of the rotational load / non-circular cross section cam portion (16) in the central portion of the rotational shaft. It is in contact.

When the vehicle turns, the operation lever (14) that moves in conjunction with the steering angle of the steering device rotates the control lever (5), and the rotation shaft (12) of the pinion gear rotates, so that the vehicle goes straight and turns. The switching cam portion (6) pushes the force of the spring (8) to lift the flange portion (7) of the control shaft (4), and the friction plate (9-2) of the control shaft (4) is moved to the pinion gear (10). ) Is pressed against the friction plate (9-1) on the back side of the tooth surface and the pinion gear (10) is released. Thereafter, the pinion gear (10) is released from being fixed regardless of the rotation angle of the rotation shaft (12) of the pinion gear until it returns straight.
When the rotation shaft (12) of the pinion gear rotates, the rotation load / non-circular cross-section cam portion (16) at the center of the shaft rotates at the same time according to the steering angle, and the rotation shaft end protruding to the tooth surface side of the side gear (11) The non-circular cross section is pushed by the elliptical cross section, and the friction plate (15-1) attached to the moving brake plate (17) is attached to the inside of the differential case (3). , A rotational load corresponding to the steering angle is applied to the side gear (11) inside the turning, and a part of the driving force inside the turning is distributed to the side gear side outside the turning.

By changing the shape of the cam part (6) for switching between straight and swivel on both sides of the rotation shaft (12) of the pinion gear, the pinion gear (10) starts to be fixed, opens and closes, the time from fixing to releasing, The degree and dead zone can be changed, and the driving performance of each car can be changed.
Since the driving force is automatically distributed to the left and right drive wheel shafts (13) by linking the steering angle and the rotation of the rotation shaft (12) of the pinion gear, it is not burdened by the driver and is independent of the driver's intention. The system automatically distinguishes between straight and turning.
When the non-slip differential device of the present invention is used alone without measuring the rotational speed ratio, the rotational speed ratio of the left and right drive wheel shafts (13) according to the steering angle, the rotational angle of the rotational shaft (12) of the pinion gear Necessary items such as the relationship between the rotation load and the rotational load are experimentally obtained in advance and set mechanically.

  In order to increase the control accuracy and more accurately distribute the driving force during turning, rotation sensors are attached to the left and right drive wheel shafts (13), and the drive wheel shafts (13 ) Is measured, compared with the ideal rotation ratio of the left and right drive wheel shafts (13), and the error is fed back to the rotation angle of the rotation shaft (12) of the pinion gear and the inside of the turn By adjusting the rotational load applied to the side gear (11), the actual rotation speed ratio of the left and right drive wheel shafts is an ideal allowable error range of the rotation speed ratio of the left and right drive wheel shafts (13). Control to fit within. (See Figure 3)

  The cam part (6) for switching the rectilinear / revolving of the rotation shaft (12) of the pinion gear moves the control shaft (4) up and down regardless of the rotation direction of the shaft, so that the pinion gear (10) is fixed and released. By rotating the rotating shaft (12) of the pinion gear at any time in the reverse direction and applying a rotational load on the side gear (11) on the outside of the turn, or by applying a strong rotational load on the side gear (11) on the inside of the turn during turning The same function as four-wheel steering becomes possible, such as producing the same phase effect.

  The non-slip differential according to the present invention distributes the driving force to the left and right driving wheels without waste even when traveling straight or turning without being burdened to the driver by interlocking with the steering device. When a car is traveling straight, the left and right drive shafts are mechanically connected directly to suppress slip travel, and when turning, the rotation sensor attached to the drive wheel shaft is used to calculate the rotation speed ratio between the left and right drive wheel shafts. By approaching the ratio, wheel wear, running stability, fuel efficiency, running performance on rough terrain and snowy roads can be expected. In addition, it is possible to expect an effective four-wheel steering effect by improving the turning performance of the car when turning, changing the lane during high speed driving, parallel parking, turning in a narrow place, etc. by arbitrarily changing the distribution of driving force .

Explanatory diagram of wheel trajectory during turning Non-slip differential structure example of the present invention Example of system using non-slip differential of the present invention

Explanation of symbols

1 drive pinion 2 drive gear 3 differential case 4 control shaft 5 control lever
6 Cam part for straight / reverse switching 7 Flange part 8 Spring (for pinion gear fixing)
9-1 Friction plate (pinion gear side)
9-2 Friction plate (control shaft side)
DESCRIPTION OF SYMBOLS 10 Pinion gear 11 Side gear 12 Pinion gear rotating shaft 13 Drive wheel shaft 14 Operation lever
15-1 Friction plate (moving friction plate side)
15-2 Friction plate (differential case side)
16 Rotating load / Non-circular cross-section cam part 17 Moving brake plate 18 Gear case

Claims (2)

   Linked with the steering device, the left and right drive wheels are directly connected when going straight, and the driving force is automatically distributed to the left and right drive wheel shafts according to the turning radius regardless of the running resistance difference of the drive wheels when turning.・ Slip / diff equipment.   Control is performed so that the error between the ideal rotation speed ratio of the left and right drive wheel shafts calculated from the steering angle of the steering device during turning and the actual rotation speed ratio of the left and right drive wheel shafts falls within a preset allowable range. A system using the non-slip differential device of claim 1.

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