JP3659422B1 - Differential gear linked with steering gear - Google Patents

Abstract

【Task】
The problem to be solved by the present invention is that when a difference in travel distance between the left and right drive wheels occurs in the current differential device, it cannot be determined whether the slip is during turning or straight travel. Reduces loss and distributes driving force appropriately to the left and right drive wheels while turning to improve maneuverability, fuel consumption, stability, and running performance, and suppress tire wear.
[Solution]
By linking the steering angle of the steering device and the differential device, the vehicle can automatically discriminate between straight and turning without burdening the driver, and when driving straight, the left and right drive wheels are directly connected. A rotation load corresponding to the steering angle is applied to the inner side gear, and the actual rotation speed ratio of the left and right drive wheel shafts is compared with the calculated rotation speed ratio with the rotation sensor of the drive wheel shaft, and the error is adjusted to the magnitude of the rotation load. -Draw back to bring it closer to the ideal speed ratio.
[Selection] Figure 3

Description

  The present invention relates to an automobile differential.

  The power of an automobile is usually distributed from a single power source to the left and right drive wheels through a transmission, a transmission device, and the like by a differential device. The differential device is a device for adjusting the difference in mileage caused by the turning radius of the drive wheel when the car turns, and its basic form is that four bevel gears face each other in a gear box. Combined, it is attached to the rotating shaft of a large-diameter bevel gear called a drive gear and rotated with a drive pinion.

  This type of differential device does not function as a differential device unless the balance of the running resistance of the left and right drive wheels is lost, and the drive wheels inside the turn are braked when the vehicle turns. The driving wheel on the outside of the turn is subjected to a force that can be forcibly dragged, and the difference in running resistance is greatly collapsed. The differential device works to increase the running resistance during turning. The driving force is distributed and moved to the driving wheels.

  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. From the wheel to the drive wheel with the lower resistance, and the power is always lost due to the flow of power to the drive wheel with the lower running resistance that receives the driving force of the car. Has an effect.

  Also, when driving on muddy ground or ice vane where the driving resistance difference between the left and right driving wheels increases, the driving force 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 this case, all of the driving force may flow to one wheel, and one wheel may idle and the vehicle may not move. Also, if one drive wheel slips or slips momentarily due to unevenness or dust on the road surface while driving at high speed, the rotational speed of the idle drive wheel momentarily increases. The driving force balance of the driving wheels is lost and the running is not stable. As an improvement measure, various limited slip differentials have been developed and put into practical use.

  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 suppress the idling of one wheel. It is mounted on.

  If the differential amount is limited more than necessary, the wheels will be locked, overloading the engine and transmission device will cause a problem in mechanical structure for safe driving. Most limited slip differentials are post-processing controls that work after a certain amount of differential is generated, and differential units that can mechanically determine whether the slip is a turn or straight travel that is originally required for the differential I can't find it right now. The limited slip differentials found in the market today tend to be complex, heavy and expensive, and it is expected that low-priced, simple, lightweight, and reliable functions will be popular.

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

  The problem to be solved by the invention is that the differential device mechanically automatically determines the two driving states of turning and straight traveling of the automobile, and the left and right driving wheels that do not force the rotation of the driving wheels during turning. The aim is to reduce the loss of driving force of the automobile by bringing it closer to the ideal speed ratio, to improve driving fuel efficiency, stability and driving performance, and to improve the tire wear suppression effect.

  By linking the differential unit with the steering device, it is possible to automatically determine whether the vehicle is running straight or turning. When driving straight, the left and right drive wheels are directly connected to eliminate slip loss. Rotational load is applied to the inner gear on the inside of the turn to distribute the driving force appropriately to the outer drive wheels, and the rotation speed ratio between the left and right drive wheel shafts is measured to give an error from the calculated design value to the side gear on the inner side of the turn. The most important feature of the differential unit is that it is possible to make it closer to ideal turning by improving the control accuracy by feeding back to the size of the load.

  In the differential of the present invention, the left and right drive wheels are mechanically directly connected when the vehicle is traveling straight, so that the linear traveling performance is improved and the traveling stability at high speeds and the difference in traveling resistance such as muddy ground are large. You can expect to improve your ability to run in a certain place. In addition, the differential of the present invention can change the driving performance of the vehicle by adjusting the timing of distributing the driving force when turning to the left and right driving wheels and the ratio of the distribution. Is distributed according to the turning radius regardless of the running resistance, and the effects such as the stability of turning, tire wear, and the improvement of fuel consumption are expected.

  In addition to being used as a differential device for two-wheel drive vehicles and four-wheel drive vehicles, it is possible to have the same effect as four-wheel steering such as anti-phase steering and in-phase steering by arbitrarily controlling the distribution of driving force. It can be expected that the parallel driving and turning radius will be improved, the stability when changing the driving lane at high speed will be improved, and the driving function of the car will be improved. In addition, the differential of the present invention is simple in structure and sufficiently competes with the current limited slip differential in terms of weight and price.

  Whether the vehicle is going straight or turning is automatically determined according to the steering angle of the steering device, and the rotation of the pinion gear is fixed during straight running by interlocking with the rotation of the pinion gear of the differential device. Is replaced by a rotation speed ratio, the actual rotation speed ratio of the left and right drive wheel axles is compared with the calculated rotation speed ratio, and the error is fed back to the magnitude of the rotation load applied to the side gear of the differential gear. It is possible to approach an appropriate mileage difference corresponding to the steering angle at the time.

    As shown in Fig. 1, an automobile (four-wheeled vehicle) is made so that all wheels pass on the circumference of concentric and different radii around the turning center O by an Acckerman mechanism so that it turns without slipping. ing. 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. The travel distance of the rear turning inner wheel and the inner turning wheel with different turning radii is the traveling distance Lo (= Ro × θ) of the outer turning wheel and the traveling distance Li (= Ri × θ) of the inner turning wheel. The difference in distance is Lo-Li = (Ro x θ)-(Ri x θ). The turning radius of the turning outer wheel is the turning radius of the turning inner wheel plus the tread width between the left and right wheels. Ro = Ri + TR Therefore, the travel distance difference between the left and right drive wheels that should be adjusted by the differential is TR × θ (rear wheel tread width × turning angle).

    Here, if the left and right tire diameters are the same, the distance traveled by the wheel is tire diameter x number of revolutions. Therefore, the calculated travel distance ratio of the left and right drive wheels when turning is the ratio of the number of revolutions of the left and right drive wheel shafts , The ratio of travel distance is Lo / Li = (Ro × θ) / {(Ro-TR) × θ} = 1 / {1- (TR / Ro)}. The ratio of the rotational speeds of the left and right drive wheel shafts is constant. When calculating the rotation speed ratio of the left and right drive wheels required for turning with the dimensions of a commercially available car, a car with a tread width of 1.6 m of the drive wheel turned with a turning radius of the turning outer wheel of 4.8 m. In this case, the rotation speed ratio between the inner and outer driving wheels is 1.50. (See Table-1)

    As shown in the explanatory diagram of FIG. 2, the differential of the present invention has a pinion gear that freely rotates at both ends of a rotating shaft (12) of a pinion gear having a non-circular cam shape (16) at the center of the shaft. Install (10) and engage the side gear (11) from both sides. Friction plates (9-1) and (15-1) are attached to the back sides of the tooth surfaces of each pinion gear and side gear. 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 friction plate (9-2) attached to the end of the pipe, and the outer end of the pipe supports the axial displacement due to the expansion and contraction of the spring (8). The differential case (3) The spline machined in the mounting hole is splined to mesh with the control shaft to prevent rotation, and the inner side of the pipe is machined to the outer diameter of the rotation shaft of the pinion gear to lift the control shaft in the axial direction. Attach the part of the jaw (7) hooked on the cam part (6).

Place the control shaft over the rotation shaft of the pinion gear with the friction plates facing each other, sandwich a spring between the differential case and the friction plate at the end of the control shaft, engage the control shaft with the spline part, and stop the rotation. -Install it in the hole of the screw. The rotating shafts of the side gear and the side gear are integrated, the drive wheel shaft (13) is connected to the rotating shaft on the back side of the tooth surface, and the side gear is connected to the front surface of the tooth surface until the shaft end surface comes into contact with the cam-shaped circular cross section at the center of the rotating shaft of the pinion gear. Extend the axis of rotation and protrude.
A control lever (5) is attached to both ends of the rotation shaft of the pinion gear that is brought out of the differential case, and is attached to an operation lever (14) of the operating device linked with the steering angle of the automobile steering device.

  When the car is moving straight, the friction plate (9-2) attached to the end of the control shaft, which is stopped by rotation by engaging with the splined mounting hole of the differential case, is attached to the back of the tooth surface of the pinion gear by the spring force. By pressing against the friction plate, the rotation of the pinion gear is fixed, the left and right drive wheel shafts are forcibly directly connected in the differential, and the rotation speeds of the left and right drive wheels are the same. The rotation position of the rotation shaft of the pinion gear at this time is such that the rotation shaft end surfaces protruding from the left and right side gears are in contact with the semicircular portion of the non-circular cam that combines the semicircular and elliptical halves of the central portion of the rotation shaft. To do.

  When the automobile turns, an operation lever linked to the steering angle of the steering device rotates the control lever, and rotates the rotation shaft of the pinion gear, thereby rotating the inner diameter of the control shaft covered on the rotation shaft of the pinion gear. The cam part (6) on both sides of the rotation shaft of the pinion gear lifts the protrusion part (7) attached to the pinion gear by pushing the spring force, thereby pressing the friction plate of the control shaft against the friction plate on the back side of the tooth surface of the pinion gear. The applied force is removed and the pinion gear is released. Also, when the rotation shaft of the pinion gear rotates, the cam shape of the non-circular cross section at the center of the rotation shaft rotates, and the friction plate attached to the side gear is pushed by pushing the rotation shaft protruding to the tooth surface side of the side gear according to the rotation angle of the shaft. It is pressed against the friction plate (15-2) attached to the differential case, a rotational load corresponding to the steering angle is applied to the side gear inside the turning, and the driving force of the side gear inside the turning is distributed to the side gear outside the turning.

  By changing the shape of the cam part (6) on both sides of the rotation shaft of the pinion gear, it is possible to change the pinion gear fixing start time, fixed opening time, time from fixing to opening, degree of opening, dead zone, etc. The driving performance can be changed depending on the individual car. Since the rotation of the pinion gear is fixed and released by linking the steering angle and the rotation of the rotation shaft of the pinion gear, the driving force is automatically distributed to the left and right drive wheel shafts by applying a rotational load according to the steering angle. Regardless of the driver's intention, the driver will not be burdened by automatically using either straight driving or turning. The relationship between the rotational speed ratio of the left and right drive wheel shafts according to the steering angle (rotation radius), the rotational load, and the rotational angle of the rotational shaft of the pinion gear is experimentally determined in advance.

  In order to improve the control accuracy of the system shown in Fig. 2 and to distribute the driving force more accurately during turning, rotation sensors are attached to the left and right drive wheel axles to drive the vehicle inside and outside the vehicle actually turning The actual rotation speed of the left and right drive wheel shafts is measured by measuring the rotation speed ratio of the wheel shafts, comparing it with the calculated rotation speed ratio of the left and right drive wheel shafts, and feeding back the error to the rotation angle of the control lever. The ratio is controlled so as to be within an allowable error range of the rotational speed ratio of the left and right drive wheel shafts in the calculation of the automobile. (See Figure 3)

The cam part (6) of the rotation shaft of the pinion gear moves the control shaft up and down to fix and release the pinion gear regardless of the rotation of the shaft. It is also possible to produce the same effect as the same phase of four-wheel steering by applying a rotational load to the side gear to produce the same effect as the reverse phase, or by applying a rotational load applied to the side gear inside the turn more strongly than during a normal turn. is there.

  Compared to a differential gear that operates only with the driving resistance of the left and right drive wheels, the power distribution ratio and distribution time of the left and right driving forces can be controlled arbitrarily according to the turning radius of the car, making it the optimal turning for each car. Can provide performance. As a result, the behavior of the vehicle during turning can be changed arbitrarily, and the tire wear-inhibiting effect, lane change during high speed running, parallel parking, turning operations in narrow places, etc. can be made smooth.

  The differential of the present invention suppresses slip traveling by mechanically connecting the left and right drive shafts when the vehicle is traveling straight (or close to straight), and at the time of turning, the left and right drive wheel shafts are detected by a rotation sensor attached to the drive wheel shaft. By automating the rotation speed of the vehicle closer to the ideal rotation speed ratio in the calculation, the driving force can be distributed to the left and right drive wheels without waste even when turning or going straight without burdening the driver. , It can be expected to be effective in many areas, such as wheel wear, running stability, improved fuel efficiency, and improved performance on rough terrain.

Explanatory drawing of the running trajectory of automobile wheels during turning Explanatory drawing of the differential device that directly connects the left and right drive wheel axles in conjunction with the steering device when traveling straight and distributes the driving force when turning Explanatory diagram of a system example that connects the left and right drive shafts directly in conjunction with the steering device when going straight, and brings the left and right drive shafts closer to the ideal rotational speed ratio when turning

Explanation of symbols

1 drive pinion 2 drive gear 3 differential case 4 control shaft 5 control lever
6 Cam part (for control shaft lifting)
7 Spline processing part (rotation stop)
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 (side gear side)
15-2 Friction plate (moving friction plate side)
16 Non-circular (circular + elliptical) cam

Claims (2)

Mount a pinion gear that freely rotates on both sides of the rotation shaft of the pinion gear whose cross section is a non-circular cam at the center of the shaft, engage the side gear and install it in the differential case, and attach it to the end of the rotation shaft of the pinion gear. A differential device in which an operation lever for rotating the rotating shaft is mounted and the rotating shaft core of the side gear in the differential case is aligned with the rotating shaft core of the drive gear.
When the automobile goes straight, the friction plate attached to the control shaft that moves in the axial direction and does not rotate is pressed against the friction plate on the back of the pinion gear by the force of the spring placed between the pinion gear and the inside of the differential case. Fixed rotation,
When the vehicle turns straight, the differential operation lever linked to the steering angle of the vehicle steering device rotates the rotation shaft of the pinion gear, and the spring that holds down the friction plate attached to the control shaft. Pull out the force and lift the pinion gear fixed state,
By linking the steering angle of the steering device and the rotation angle of the rotation shaft of the pinion gear, the non-circular cam portion at the center of the rotation shaft of the pinion gear pushes the rotation shaft end surface protruding to the tooth surface side of the side gear according to the steering angle. By pressing the friction plate attached to the back of the side gear against the friction plate attached to the inside of the differential case, a rotational load is applied to the side gear according to the steering angle, and the driving force of the vehicle is adjusted to the left and right drive wheel axles according to the steering angle. A differential device characterized in that the differential device is distributed.   The differential device according to claim 1, wherein rotation sensors are attached to the left and right drive wheel shafts connected to the side gear, respectively, to change the rotation direction of the rotation shaft of the pinion gear and how to apply the rotation load. When steering, the calculated rotational speed ratio of the left and right drive wheel axles calculated from the steering angle of the steering device is compared with the actual rotational speed ratio, and the error is reflected in the magnitude of the rotational load applied to the side gear. 2. The system using a differential device according to claim 1, wherein an appropriate rotational load is applied to the side gear so that the actual rotational speed ratio of the left and right drive wheel shafts is within an allowable error range of the calculated rotational speed ratio.

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