JPH0150779B2 - - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention a. Field of Industrial Application The present invention relates to an improvement in a limited slip differential used in automobiles and other vehicles, and particularly relates to an improvement in a limited slip differential used in automobiles and other vehicles. The present invention relates to a differential device with a differential limiting mechanism that can be used as a differential or as a limiting differential.

b. Prior Art A differential device for automobiles and other vehicles is a device that rotates both wheels at the same rate when the vehicle is traveling straight, and when turning, changes the angular velocity of both wheels to prevent wheel slippage and ensure smooth turning. be. However, in a vehicle equipped with a differential, if one wheel enters an area with a low coefficient of friction, such as a muddy or frozen road surface,
The wheels on that side spin, and sufficient driving force is not transmitted to the wheels on the other side, making it difficult to escape. This is for differential operation that transmits the same torque to both wheels.
This is because only the same torque as the idling wheel with a smaller friction coefficient is transmitted to the wheel with a larger friction coefficient.

Therefore, a differential limiting mechanism is provided to compensate for the drawbacks of this differential device. As seen in Japanese Patent Publication No. 38-18254, a conventional differential limiting mechanism limits the differential by providing a friction clutch that is constantly pressed by a spring between the differential side gear and the differential case. be. Furthermore, as described in Japanese Patent Publication No. 47-12770, for example, there is a device in which a meshing clutch in which pawls or spline teeth can slide is provided between the differential side gear and the differential case, thereby making it possible to limit the differential movement of the friction clutch. .

c Problems to be Solved by the Invention Of the above-mentioned conventional differential devices with a differential limiting mechanism, those equipped with a friction clutch that is constantly pressed by a spring do not operate the differential even during normal turns when differential limiting is unnecessary. Therefore, there are problems such as accelerated wear of the friction plates, shortening the period for repair or replacement, and lowering fuel efficiency due to power loss.

Furthermore, in the case of a clutch having an engaging clutch of pawls or spline teeth, when the clutch is engaged due to limited differential movement, the peaks of the pawls or spline teeth may come into contact with each other in a stationary state and do not engage. Therefore, when the driver lightly steps on the accelerator to create a rotation difference between the two, the rotation difference between the two suddenly increases when one wheel is on a muddy or frozen road surface. As a result, the ridges of the pawls or spline teeth interfere with each other and do not mesh with each other, resulting in wear or damage to the tips of the ridges. Furthermore, with this mechanism, it is necessary to continue pushing the clutch with the fork until the peaks and valleys of the clutch engage, and when a driving force is applied, the fork must continue to pull out the sleeve due to the resistance caused by the engagement. Therefore, there is a problem in that heat generation and wear occur at the contact portion between the fork pin and the sleeve, impairing the durability of the contact portion.

The present invention relates to a differential gear with a differential limiting mechanism, and is an object of the present invention to solve the problems of the above-mentioned conventional differential gear. That is, the first object of the present invention is to enable the driver to arbitrarily select and switch between the normal differential and the limited differential, regardless of whether the relative rotational speed between the differential side gear and the differential case is slight, medium, high, or stopped. The aim is to ensure that the process can be carried out reliably, quickly and smoothly. The second purpose is to minimize the time for pressing and pulling out the sleeve by the fork, thereby preventing wear and heat generation at the contact portion between the fork pin and the sleeve, thereby improving durability. Also the third
The first is to reduce the operating force needed to switch from the differential limited state to the normal differential, and the fourth is to easily and appropriately set the required time when the friction clutch is released.At the same time, the structure is simpler and more compact. The objective is to make the process easier and easier to manufacture.

B. Arrangement of the Invention a Means for Solving the Problems The present invention provides a friction clutch 3 which is pressed by the advancement of the spring plate 2 in the clutch case 1.
In the differential device with a differential limiting mechanism, the spring plate 2 has a boss portion 7 which is fitted in the circumferential direction. Several through holes 8 are formed, and a movable body 9 having a height greater than the depth thereof is engaged with each through hole 8, and the sleeve 6 is provided with a movable body 9 on the outside when the sleeve for differential is pulled out. A sleeve slope 12 that pushes the movable body 9 of the hole 8 toward the clutch case 1 side, a pressing side surface 13 that presses and locks the movable body 9 against a clutch case slope 15 described later for locking the spring plate, and A recess 10 is formed in which a part of the movable body 9 can be engaged in order to release the lock when the sleeve is pushed in, and the clutch case 1 has a recess 11 on the inner side in which a part of the movable body 9 can be engaged. A clutch case slope 15 is formed to move the movable body 9 pushed by the sleeve slope 12 in the anti-friction clutch direction in order to cause the spring plate to retreat when the sleeve for the normal differential is pulled out.

In the above configuration, it is preferable that the movable body 9 is a steel ball, for example, as in the illustrated embodiment. In that case, the through hole 8 of the boss portion 7 of the spring plate 2 should be a round hole, and each of the recesses 10 and 11 on the outer side of the sleeve 6 and the inner side of the clutch case 1 should form an annular recess around each. Good. Similarly, the sleeve slope 12 on the outer side of the sleeve 6 is the side surface of the recess 10 on the friction clutch side, and is preferably an outer conical surface that becomes larger in diameter on the same side, and the pressing side surface 13 is the outer cylindrical surface that follows it. And it is sufficient. Further, the clutch case slope 15 on the inside of the clutch case 1 may be an inner conical surface having a smaller diameter on the friction clutch side, and for example, such an annular body may be mounted on the inner circumferential surface of the clutch case 1.

However, unlike the above, the movable body 9 may not be a steel ball but may be wedge-shaped, for example. In that case, the through hole 8 becomes square, and the recesses 10 and 11, the sleeve slope 12, the pressing side surface 13, and the clutch case slope 15 do not need to be formed in an annular shape around the periphery since the movable body 9 does not roll. Instead, it is sufficient to form them only at positions corresponding to each through hole 8.

The depths of the recesses 10 and 11 are such that even when the movable body 9 is pressed and engaged, the center of the movable body 9 is in the through hole 8 in order to facilitate return when the pressure is released. It is better to let it be.

The fork 5 is preferably connected at one end to an external means such as a piston of a hydraulic cylinder 4, and at the other end to the sleeve 6 by a fork pin 16. As shown in FIG. 5, the boundary 27 between the sleeve slope 12 and the pressing side surface 13 of the sleeve 6 is preferably formed into a curved surface in order to reduce wear and allow smooth movement of the movable body 9.

In the figure, a differential carrier 17 has a drive pinion 18 connected to the engine like a known differential device, and a differential case 20 and the clutch case 1 are fixed to a ring gear 19 that meshes with the drive pinion 18. Inside the differential case 20, an appropriate number of differential pinions 22 that are rotatable around a pinion shaft 21 are provided, and differential side gears 23 and 24 on an axle (not shown) orthogonal to the pinion shaft 21 are respectively meshed with the differential pinion 22. There is. 25 is a differential box, and 26 is a fork shaft.

b Function The operating state of the present invention is as follows. In Fig. 1, the upper part of the X-X line shows when the sleeve for the normal differential is pulled out, and the lower part shows when the sleeve for limiting the differential is pushed in. FIGS. 2 to 5 show the main parts of each state. First, for a normal differential, the fork 5 is actuated by the cylinder 4, and the sleeve 6 is pulled out in the anti-friction clutch direction (leftward in the figure) as shown above the line X-X in Figure 1 and in Figure 2. I'll keep it. At this time, the movable body 9 is pushed toward the clutch case 1 by the sleeve slope 12, and is pressed against and locked to the clutch case slope 15 by the pressing side surface 13. Movable body 9
Due to this locking, the spring plate 2 is also locked in the retracted position against the pushing force of the subring 14 and does not move forward, so the friction clutch 3 is maintained in the open state. In this state, similar to a known differential device, engine rotation and torque rotate and drive the differential box 25 via the drive pinion 18 and ring gear 19, and the pinion shaft 21 causes the differential pinion 22 to revolve. Regarding the above-described sleeve withdrawal, the present invention has no meshing part in the direction of movement of the sleeve 6, and the clutch case 1 and the slopes 15, 12 on the inner and outer peripheries of the sleeve 6 and the movable body 9
It consists of Therefore, even when a driving force is applied, there is no resistance due to meshing when the sleeve is pulled out, unlike in the meshing portion, and there is no need to maintain force in the drawing direction. Therefore, the time for holding the drawer can be kept to a minimum, and wear and heat generation at the contact portion of the fork pin 16 and the sleeve 6 can be suppressed.

Now, if the rotational resistance torques of the left and right wheels, and thus the left and right differential side gears 23 and 24, are the same, the differential pinion 22 only revolves, and both side gears 23 and 24 also rotate at the same speed as the differential box 25, Straight driving is performed. If left and right differential side gear 2
If there is a difference between the rotational resistance torques of 3 and 24,
While the differential pinion 22 revolves, it rotates relative to the pinion shaft 21 to slow down the rotation speed of the differential side gear on the side with greater rotational resistance torque,
The other differential side gear is made faster to enable smooth cornering.

On the other hand, if one wheel enters a place with a small coefficient of friction, such as a muddy ground or an icy road,
The rotational resistance torque of the wheel becomes almost zero. As a result, a differential action is activated and only that wheel slips, and rotational torque is not transmitted to the other wheel, making the vehicle unable to drive. In such a state, when the driver issues an instruction to switch the flow path to the cylinder 4 from the driver's seat, the sleeve 6 is pushed through the piston/fork 5 and moved in the direction of the friction clutch 3 (to the right in the figure). Just let it happen.

In the above case, the sleeve 6 replaces the pressing side surface 13 that presses and locks the movable body 9 to the clutch case slope 15, as shown in the lower part of the line X-X in FIG. 1 and in FIG. Thus, the recess 10 moves to the inside position of the movable body 9. Therefore, the movable body 9 engages with the recess 10 and the locked state is released, and the movable body 9
The locked state of the spring plate 2 via is also released. The spring plate 2 is now moved forward, that is, in the direction of the friction clutch, by the pushing force of the spring 14, and the friction clutch 3 is brought into close contact with the spring plate 2. Since the differential movement is limited by the close contact of the friction clutch 3, rotational resistance torque is generated in the differential side gears 23 and 24, and sufficient rotational torque is transmitted to both wheels, making it possible to escape from muddy or frozen roads. becomes. Regarding the sleeve insertion described above, the present invention has a structure in which there is no meshing portion in the moving direction of the sleeve 6, as described above. Therefore, since there is no interference between ridges unlike in the case of a device with meshing portions, the time required for holding pressure by the fork 5 is kept to a minimum, and wear and heat generation at the contact portion of the fork pin 16 and the sleeve 6 can be suppressed.

Next, in order to release this differential limited state, the driver issues an instruction to switch the flow path to the cylinder cylinder 4 from the driver's seat in the same manner as described above, pulls out the sleeve 6 via the fork 5, and moves it to the left as shown in FIG. Just move it back closer. At this time, as the sleeve 6 slides, the sleeve slope 12 pushes the movable body 9 toward the recess 11 of the clutch case 1, so the movable body 9 moves along the clutch case slope 15 in the anti-friction clutch direction (leftward in the figure). ). Due to this movement of the movable body 9, the spring plate 2 also retreats in the same direction and returns to its original retreat position, so that the pressing force of the spring 14 on the friction clutch 3 is released instead of before.
Sufficient space is created between the friction clutch plates.

When the friction clutch 3 has a sufficient gap, the pressing side surface 13 of the sleeve 6 presses the movable body 9, which is engaged in the recess 11 of the clutch case 1, against the clutch case slope 15 and locks it. This state is the same as that previously explained in FIG.
It will not move forward because it is locked. This results in
The open state of the friction clutch 3 is maintained and the normal differential state is established, allowing normal driving. Further, in the above case, even if the oil pressure of the cylinder 4 that pulls out the sleeve 6 via the fork 5 is zero, the spring plate 2 is
It is locked through pressure contact and locking with 5, and it does not move forward. Therefore, the open state of the friction clutch 3 is maintained.

In addition, as in the illustrated embodiment, the movable body 9 is a steel ball,
The sleeve 6 is cylindrical, and the recess 10, sleeve slope 12, and pressing side surface 13 are each annular, and the recess 11 of the clutch case 1 and the clutch case slope 1
If the movable member 5 is also annular, the contact portion with the movable body 9 changes in the circumferential direction, thereby reducing local wear.

C. Effects of the Invention As is clear from the above, the differential device with a differential limiting mechanism of the present invention has the following effects.

a Regardless of whether the relative rotational speed of the differential side gear and the differential case is slight, medium, or high, or when the driver is stopped, the driver can select and switch between the normal differential and the limited movement from the driver's seat in a reliable, quick, and smooth manner. Crab can be done. That is, with conventional clutches using claws or spline teeth, the ridges may come into contact and not engage immediately, or the tips of the ridges may be damaged. In addition, in conventional friction clutches that are constantly pressed by a spring, the friction plates suffer severe wear and power loss is high. However, in the present invention, with the above-described configuration, selection and switching between normal differential and limited differential can be performed reliably, quickly, and smoothly at any time, and chipping, wear, and power reduction of contact parts are almost eliminated. It can be eliminated.

b. Durability can be improved by suppressing wear and heat generation at the contact area between the fork pin and sleeve. In other words, if the sleeve has an engaging part such as a claw in the direction of movement,
When the sleeve is pushed in by the forks, there is interference between the ridges, so it is necessary to maintain the pressure caused by the movement of the forks. Furthermore, when the sleeve is pulled out by the fork, if a driving force is applied, a resistance force against the sleeve pulling out is generated due to the meshing, so it is necessary to maintain the force in the pulling direction. Therefore, since holding time is required for the fork to press and pull out the sleeve, abrasion and heat generation occur between the contact portion of the fork pin and the sleeve, resulting in a lack of durability.

However, in the present invention, the clutch case is composed of slopes on the inner and outer peripheries of the sleeve and a movable body, and there is no meshing part in the direction of movement of the sleeve. Therefore,
There is no interference between the meshing parts when pushing the sleeve in,
Even if a driving force is applied when the sleeve is pulled out, there is no resistance in the drawing direction. Therefore, in the present invention, the pressing and drawing holding time can be minimized,
It prevents wear and heat generation between the contact part of the fork pin and the sleeve, greatly improving durability.

On the other hand, if the fork continues to press the sleeve at that position to maintain the change after switching from limited differential to normal differential, the contact area between the fork pin and the sleeve will be severely worn. However, in the present invention,
The spring plate in the retracted position is locked through the locking of the movable body pressed by the sleeve.
Therefore, even if the hydraulic pressure of the fork actuating cylinder is reduced to zero and the pressure by the fork is released, the locked state is maintained, and wear and heat generation at the contact portion between the fork pin and the sleeve can be prevented.

c. The force required to pull out the sleeve for switching can be smaller than the force of the spring for pressing the friction clutch. That is, when the sleeve is pulled out, the movable body is moved through the sleeve slope, and this movement causes the spring plate to move against the spring. Therefore, since the force required to pull out the sleeve is proportional to the inclination angle of the sleeve slope, the force required to draw out the sleeve can be easily set to a small value by reducing the inclination angle.

d) It is easy to appropriately set the required time when the friction clutch is released. That is, since the angle of inclination of the slope of the clutch case that the movable body that locks the spring plate comes into contact with is proportional to the increase or decrease of the above-mentioned required distance, an appropriate distance can be set depending on the angle of inclination depending on the number of friction clutches, etc. 〓 can be easily set.

e Moreover, since the configuration of the present invention is simple and can be miniaturized, the space of the existing device can be used as is, and manufacturing can also be facilitated.

[Brief explanation of drawings]

The figures show an embodiment of the present invention. Fig. 1 is a cross-sectional plan view of the whole, Fig. 2 is a cross-sectional plan view of main parts during normal differential operation, and Fig. 3 is a cross-sectional plan view of main parts when differential is limited. FIG. 4 is a cross-sectional plan view of the main part when the sleeve is pulled out, and FIG. 5 is an enlarged cross-sectional plan view of a part of the sleeve. Drawing numbers 1...Clutch case, 2...Spring plate, 3...Friction clutch, 4...External means, 5...Fork, 6...Sleeve, 7...
Boss portion, 8... Through hole, 9... Movable body, 10, 11
... recess, 12 ... sleeve slope, 13 ... pressing side surface, 14 ... spring, 15 ... clutch case slope.

Claims (1)

[Claims] 1. A differential limiting mechanism that includes a friction clutch 3 that is pressed by the advancement of a spring plate 2 and a sleeve 6 that is slidable toward the friction clutch through a fork 5 that is actuated by an external means 4 in the clutch case 1. In the differential gear, an appropriate number of through holes 8 are formed in the boss portion 7 of the spring plate 2 in the circumferential direction, and a movable body 9 having a height greater than the depth of each through hole 8 is formed in the spring plate 2 in the circumferential direction.
When the sleeve 6 is pulled out, the movable body 9 of each through hole 8 is attached to the outer side of the sleeve 6.
Sleeve slope 12 that pushes the clutch case 1 side
, a pressing side surface 13 that presses and locks the movable body 9 to a clutch case slope 15 described later in order to lock the spring plate 2, and a portion of the movable body 9 that releases the locking when the differential limiting sleeve is pushed in. The clutch case 1 is provided with a recess 10 in which a part of the movable body 9 can be engaged, and a recess 11 on the inside of the clutch case 1 in which a part of the movable body 9 can be engaged, and a recess 11 in which the spring plate 2 is retracted when the sleeve for the normal differential is pulled out. Therefore, the differential gear with a differential limiting mechanism is provided with a clutch case slope 15 that moves the movable body 9 pushed by the sleeve slope 12 in the anti-friction clutch direction.