JPH0415132B2 - - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention (a) Industrial Application Field The present invention provides a differential limiting device, that is, a differential device with limited differential for automobiles and other vehicles, in which a normal differential and a differential can be changed by external operation. This invention relates to a switching mechanism that performs restriction.

b. Prior Art In a differential limiting device, switching between a differential and a limited differential is generally performed by moving a sleeve in a clutch case using a piston of a fluid pressure cylinder via a fork, etc., and thereby switching the clutch. There is.

For the above differential switching, positioning of the moving sleeve is important, and conventional means for positioning this sleeve include the following, for example. One is to position the piston of the differential switching cylinder by hitting it against a step provided inside the cylinder or a cover on the side of the cylinder. In other cases, positioning is not performed using a cylinder, but a stopper is provided on a part of the sleeve, or a claw clutch is provided at the tip of the sleeve, and positioning is performed when the tip comes into contact with the sleeve.

c. Problems to be Solved by the Invention Of the switching mechanisms of differential limiting devices, the one in which the sleeve is positioned by applying a piston to a step or a side cover in the cylinder as described above has a difference in the tooth contact of each bevel gear and It is not possible to adjust the batch or to respond to changes in the set position due to the accumulation of machining tolerances for each part. In order to cope with this, it is necessary to provide a margin for positioning errors in the adjustment of each component in the action portion of the sleeve. This margin is twice the adjustment error of each part, but if other parts are moved by the action part of the sleeve, twice as much margin is required between them, and a total of four times the margin is required. Must be established. If there are more moving parts, twice as much room is required for each one, so that the originally unnecessary room becomes twice, three times, eight times, etc. in total. This increases the size of the entire device including the sleeve, and requires a special design concept that allows for such a margin. In addition, since the piston is stopped by hitting the stepped part of the cylinder or the side cover, an impact noise is generated and the threaded part may loosen due to the impact force. There are some models that adjust the amount of piston movement by inserting a shim or the like between the cylinder and the side cover, but this has problems such as the need to remove and install the cover each time the adjustment is made. be.

On the other hand, in models where positioning is performed on the sleeve side rather than the cylinder, the hydraulic tank is usually installed higher than the cylinder, so even if the hydraulic pressure in the cylinder is switched to drain pressure after moving the fork, the oil pressure due to the difference in height is Residual pressure is added to the cylinder due to column pressure and pipe resistance. Therefore, the fork pin constantly presses against the inner surface of the groove of the sleeve via the piston fork. Moreover, the deflection of the fork, etc., which occurs when the fork moves, tries to restore its original shape, and still acts as a force that constantly presses the fork pin against the inner surface of the groove of the sleeve. Therefore, there is a problem in that abrasion and heat generation occur between the fork pin and the inner surface of the groove of the sleeve, resulting in faster repair or replacement.

The present invention aims to solve the above-mentioned problems of the conventional switching mechanism of a differential limiting device. That is, the first objective is to make it possible to easily and quickly adjust the amount of piston movement from outside the cylinder, to minimize the amount of movement of the piston, fork, sleeve, and actuating parts due to sleeve movement, and to downsize the device. At the same time, the purpose is to eliminate the need for special design concepts that take into account various errors.

A second purpose is to attenuate the impact force when the piston hits the positioning part of the cylinder, eliminate impact noise, and prevent the threaded part from loosening due to the impact force.

A third purpose is to prevent the fork pin from coming into pressure contact with the inner surface of the groove of the sleeve due to residual pressure in the cylinder chamber or deflection during fork operation, thereby improving the durability of the fork pin.

B. Structure of the Invention a Means for Solving the Problems The present invention moves the sleeve 4 via the fork 3 with the piston 2 of the external differential switching cylinder 1 to switch between normal differential and limited differential. In the switching mechanism of the differential limiting device, adjusting bolts are provided on both sides of the cylinder 1 and are screwed into female threaded portions 7 and 8 on the inner periphery so as to form side walls of the cylinder chambers 5 and 6, respectively. 9, 10 are installed internally, and each adjusting bolt 9, 10 is provided with an external adjustment part 11, 12 for moving in the axial direction, and a stopper part 13, 14, and an elastic material 1 for buffering and pushing back the piston 2 is provided on one side between the opposite sides of the piston 2 and the adjusting bolts 9 and 10.
5 and 16, and the fork pin 17 at the end of the fork 3 has a groove 18 in the sleeve 4 having a width k that is slightly larger than the sum of the return amount l of the fork pin 17 due to the pushing back of the piston 2 and the width m of the pin 17. It is configured to engage with the

In the above configuration, the female threaded portions 7 and 8 on the inner periphery of both sides of the cylinder 1 may be provided with adjusting nuts 19 and 20 with female threaded portions 7 and 8 on the cylinder 1 as shown in the illustrated example, but the cylinder 1 is not limited to this. 1 itself or the inner periphery of side covers 36 and 37, which will be described later.

The external adjusting parts 11 and 12 for moving the adjusting bolts 9 and 10 in the axial direction are provided with outwardly protruding parts 2 on each adjusting bolt 9 and 10, for example, as shown in the illustrated example.
1 and 22, and a hook portion for a rotation tool (not shown) may be formed on the protrusions 21 and 22.

The elastic members 15 and 16 may be disc springs, for example, and may be provided on the sides of the adjusting bolts 9 and 10 facing the piston as shown in the figure, but are not limited thereto and may be provided on each side of the piston 2. The buffering force received by the elastic members 15 and 16 before the piston 2 comes into contact with the stoppers 13 and 14 is
Of course, it is necessary to work under the maximum deflection of 5.16. The stopper portions 13 and 14 may be configured, for example, as the side surfaces of the adjuster bolts 9 and 10 as shown in the figure, so that the side surfaces of the piston 2 are received, but the stopper portions 13 and 14 are not limited thereto.
The piston 2 may be stopped with the two parts in between.

The return amount l of the fork pin 17, that is, the elastic material 1
The amount by which the fork pin 17 returns via the fork 3 due to the movement of the piston 2 due to the push-back forces 5 and 16 is:
The width should be larger than the deflection of the fork 3 when moving the sleeve 4 and the gap between the piston 2 and the fork pin 17, and slightly smaller than the difference n between the width k of the groove 18 of the sleeve 4 and the width m of the fork pin 17. Set it to . As a specific means for this setting, for example, in order to perform the buffering at a level below the maximum deflection of the elastic members 15 and 16, the side surface of the piston 2 or the adjuster bolt 9, as shown in the illustrated example, may be used.
Recessed holes 25 and 26 with openings larger than those of the elastic members 15 and 16 are formed on the side surface of the elastic members 10 opposite to the piston, and the above settings can be made depending on the depths of the recessed holes 25 and 26. However, the present invention is not limited thereto, and such settings may be made using the elastic members 15 and 16, or similar settings may be made using the width k of the groove 18 of the sleeve 4 or the width m of the fork pin 17.

A differential limiting device using this switching mechanism has a piston 2 of an external differential switching cylinder 1 as described above.
Then, slide the sleeve 4 through the fork 3,
Any device that can switch between normal differential and limited differential will suffice, but one example will be explained using an illustrated example. The sleeve 4 is provided inside the clutch case 27 so as to be movable in the axial direction with the boss portion of the spring plate 28 in between. Reference numeral 29 denotes a movable body, for example, a steel ball, which engages with a through hole 30 in the boss portion of the spring plate 28, and its height is greater than the depth of the through hole 30. 31 is the sleeve recess;
A portion of the movable body 29 is formed on the side circumference of the sleeve 4 so that it can be engaged with when the sleeve 4 is pushed in to limit differential movement. A sleeve slope 32 is formed on the side circumference of the sleeve 4 so as to push the movable body 29 in the through hole 30 toward the outer clutch case 27 when the sleeve 4 is normally pulled out for differential use.
Reference numeral 33 denotes a pressing side surface, which is also formed on the side periphery of the sleeve 4 following the sleeve slope 32 so as to press and lock the movable body 29 against the clutch case slope 34 described later in order to lock the spring plate 28 when the sleeve 4 is pulled out. It has been done.

Reference numeral 35 denotes a clutch case recess, which is formed in the inner peripheral portion of the clutch case 27 so that a portion of the movable body 29 can be engaged therewith. 34, a clutch case slope is formed on the inner peripheral part of the clutch case 27 so that when the sleeve 4 is pulled out, the spring plate 28 is moved back, and the movable body 29 pushed by the sleeve slope 32 is moved in the anti-friction clutch direction. There is.

In the figure, 23, 24 are fluid inlets, 36,
Reference numeral 37 designates the side cover of the cylinder 1, and in the case where the adjusting bolts 9 and 10 have protrusions 21 and 22, it is pivotally supported in the center hole, and the male threaded part is fixed with lock nuts 38 and 39. It is possible. Reference numerals 40 and 41 designate elastic material mounting portions that protrude inwardly from the adjusting bolts 9 and 10, and holes 42 and 43 are formed on both sides of the piston 2 to which they can be engaged. 44 is a friction clutch.

b. Effect To use the switching mechanism of the differential limiting device according to the present invention, the following adjustments are first made.

Fluid pressure is applied to the cylinder chamber 5 of one side of the cylinder 1 (left side in Figures 1 and 2) to force the piston 2 to the other side (right side in Figures 1 and 2). The side surface of the piston on the moving side is pressed against the stopper portion 14 of the adjusting bolt 10 on that side against the pressing force of the elastic member 16. In this state, the adjusting bolt 10 is turned using the external adjustment part 12, and by moving the bolt 10 in the axial direction (left and right directions in the figure), the piston 2 is moved together, and the sleeve is inserted through the fork 3 and the fork pin 17. 4 in the axial direction. If the sleeve 4 is in a predetermined setting position, that is, in the differential limiting device as shown in FIG.
When the adjustment bolt 10 is at the predetermined setting position relative to 9, stop the adjustment bolt 10 and tighten the lock nut 39.
to stop rotation. As a result, accurate positioning without error is achieved in a state in which the piston 2 is moved to the right for normal differential use and the sleeve 4 is pulled out via the fork 3 and the fork pin 17.

Furthermore, fluid pressure is applied to the other cylinder chamber 6 of the cylinder 1 (the right side in FIGS. 1 and 2), and the piston 2 is moved to the left in the figures, resisting the pressing force of the elastic member 15. It is brought into pressure contact with the stopper portion 13 of the adjusting bolt 9 on the moving side. In this state, as above,
The adjustment bolt 9 on the moving side is moved in the axial direction, and the sleeve 4 is moved to a predetermined set position, that is, the position where the groove 18 of the sleeve 4 that engages the fork pin 17 is set by the amount of movement corresponding to the wear of the friction clutch 44. When the adjustment bolt 9 is reached, stop the adjuster bolt 9 and lock it with the lock nut 38.

After the above adjustment, the differential limiting device equipped with this switching mechanism is mounted on the vehicle, but normally when the sleeve 4 is pulled out for the differential, only one side (Figures 1 and 2) is operated. What is necessary is to apply fluid pressure to the cylinder chamber 5 on the left side). As a result, the piston 2 moves toward the other side (toward the right in the figure) as shown in Fig. 1, but the side surface of the piston on the moving side touches the adjusting bolt 1.
Before it comes into contact with the stopper portion 14 of 0, it hits the elastic member 16 and is buffered as shown in FIG. In the illustrated example, first, the inner surface of the recessed hole 26 on the right side of the piston 2 comes into contact with the elastic material 16, and the moving force of the piston 2 is attenuated.

Thereafter, the piston 2 further moves in the same direction, and the piston side surface on the moving side hits the stopper part 14 of the adjustment bolt 10 and stops. As described above, this stop position is a position where the sleeve 4, which moves via the fork 3 and fork pin 17 due to the movement of the piston 2, stops accurately at a predetermined set position.

Thereafter, the fluid pressure in the cylinder chamber 5 may be switched to the drain pressure. In this state, the pressing force of the elastic member 16 overcomes the residual pressure of the fluid and the sliding resistance of the piston 2, and the amount of deflection generated during the previous operation of the fork 3 and the gap between the piston 2 and the fork pin 17 Push the piston 2 back to the left in FIGS. 1 and 2 by a slightly larger amount. In this case, if the differential device has the configuration shown in the illustrated example, the movable body 29 that is in contact with the clutch case slope 34 is in pressure contact with the pressing side surface 33 of the sleeve 4, so that the sleeve 4 is not locked. It's stopped. Then, as the piston 2 is pushed back to the left, the fork pin 17 is moved through the fork 3.
is also moved to the right by a corresponding return amount l as shown in FIG.

This return amount l is determined by the groove 1 of the sleeve 4 as described above.
8 and the width m of the fork pin 17. Therefore,
When the sleeve 4 was pulled out, the left side surface of the fork pin 17 was in contact with the left inner surface of the groove 18 of the sleeve 4 as shown in FIG.
maintained without contacting any of the inner surfaces of the

Next, if the sleeve 4 is to be pushed in to limit the differential, fluid pressure may be applied to the right cylinder chamber 6 in FIGS. 1 and 2, contrary to the above. As a result, the piston 2 moves to the left in the figure, but similarly to the above, the moving side is first buffered by the elastic material 15, and after damping, it comes into contact with the stopper portion 13 of the adjustment bolt 9 and is stopped. This stop position is located at the groove 18 of the sleeve 4.
is the position at which the friction clutch 44 engages with the fork pin 17 by a movement amount corresponding to the wear of the friction clutch 44. In this case as well, when the fluid pressure in the cylinder chamber 6 is set to drain pressure, the piston 2 is pushed back to the right by the push back force of the elastic member 15, and the fork pin 17 is also returned to the left. Due to this return of the fork pin 17, the contact between the fork pin 17 and both inner surfaces of the groove 18 of the sleeve 4 is eliminated in the same manner as described above.

C. Effects of the Invention a According to the present invention, the amount of piston movement of the differential switching cylinder can be easily adjusted from outside the cylinder, and the amount of movement of the sleeve is minimized to reduce the size of the entire device. be able to. In other words, the conventional method of positioning the piston by applying it to the stepped part or side cover in the cylinder cannot accommodate the adjustment of the tooth contact and backlash of each bevel gear, or the changes in the set position due to the accumulation of machining tolerances of each part. . In addition, in order to accommodate this, it is necessary to provide a margin that is more than twice the adjustment error of each component in the sleeve's action part and each action part that is linked to the sleeve, which increases the size of the entire device and requires such a margin. A special design concept was needed to anticipate this. Furthermore, in the case where a shim or the like is interposed between the cylinder and the side cover to adjust the amount of piston movement, it is necessary to remove and attach the side cover each time the adjustment is made.

However, in the present invention, as described above, the adjustment bolt with a stopper part is installed inside the cylinder, and it is movable by the external adjustment part.
The amount of piston movement can be easily adjusted from outside the cylinder in response to various adjustments and changes in setting position. Therefore, the amount of movement of the sleeve can be kept to the minimum necessary, and the device can be made more compact.
There is no need for a special design concept that allows for a margin due to many adjustment errors, and design and manufacturing are also facilitated.

b Attenuates the impact force when the piston hits the positioning part of the cylinder, eliminates impact noise, and
Prevents screws from loosening. That is, in the conventional piston that is positioned by hitting it against the stepped part of the cylinder or the side cover, the impact at that time causes an impact sound and the threaded part loosens. In contrast, in the present invention, as described above, an elastic material for buffering and pushing back is interposed on the opposing sides of the piston and the adjusting bolt. As a result, the impact force is attenuated, impact noise is eliminated, and the screw portion can be prevented from loosening.

(c) The durability of the fork pin can be improved by minimizing the time that the fork pin contacts the inner surface of the groove of the sleeve. In other words, in the case where differential switching is performed by moving the sleeve through the actuation of the fork by the movement of the piston, even if the cylinder chamber is at drain pressure, the fork pin may not enter the groove of the sleeve due to residual pressure or deflection when the fork is actuated. It is constantly pressed against the sides. As a result, fork pins need to be repaired or replaced sooner due to wear and heat generation.

However, in the present invention, as described above, an elastic material is interposed between the piston and the adjuster bolt to buffer the piston and push it back, and the fork pin is made by the sum of the width of the piston and the amount of return of the pin due to the return of the piston. It is engaged with a slightly wide groove in the sleeve. Therefore, when the cylinder chamber is brought to drain pressure after the piston has moved, the piston is pushed back by an amount slightly larger than the amount of deflection during the previous fork operation or the gap between the piston and the fork pin due to the pushing back force of the elastic material. This return of the piston also returns the fork pin via the fork, but the amount of return is set smaller than the gap, which is the difference between the width of the groove and the width of the pin. Therefore, the fork pin does not come into contact with both inner surfaces of the groove of the sleeve, suppressing wear and heat generation of the pin, and greatly improving the durability of the pin.

[Brief explanation of drawings]

The figures show an embodiment of the present invention; FIG. 1 is a cross-sectional plan view of the main parts of the switching mechanism, FIG. 2 is a cross-sectional plan view of an operation limiting device with the switching mechanism, and FIG. 3 is a cross-sectional plan view of the switching mechanism. Fig. 4 is an enlarged plan view showing the positional relationship between the groove of the sleeve and the fork pin when the sleeve is pulled out, and Fig. 5 shows the positional relationship between the groove of the sleeve and the fork pin after the fork pin returns. FIG. Drawing code: 1...Cylinder, 2...Piston,
3...Fork, 4...Sleeve, 5, 6...Cylinder chamber, 7, 8...Female threaded part, 9, 10...Adjustment bolt, 11, 12...External adjustment part, 1
3, 14... Stopper portion, 15, 16... Elastic material, 17... Fork pin, 18... Groove, k...
Groove width, l...Return amount, m...Pin width.

Claims (1)

[Claims] 1 Piston 2 of external differential switching cylinder 1
Then, move the sleeve 4 via the fork 3,
In the switching mechanism of a differential limiting device that switches between a normal differential and a limited differential, each female threaded portion 7 on the inner circumference is formed on both sides of the cylinder 1 so as to form the side walls of the cylinder chambers 5 and 6, respectively. , 8 are installed internally, and each adjusting bolt 9, 10 is provided with an external adjustment part 1 for movement in the axial direction.
1 and 12 are provided, and stopper portions 13 and 14 of the piston 2 are provided on the side opposite the piston of each adjusting bolt 9 and 10, and one of the stopper portions 13 and 14 is provided between the opposite side surfaces of the piston 2 and the adjusting bolt 9 and 10 on each side. Elastic material 15, 1 for buffering and pushing back the piston 2 on the side surface
6, and fork pin 1 at the end of fork 3.
7 is configured to engage with the groove 18 of the sleeve 4 having a width k that is slightly larger than the sum of the return amount l of the fork pin 17 due to the pushing back of the piston 2 and the width m of the pin 17. , differential limiting device switching mechanism.