JPH0361053B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dog clutch for switching between two wheels and four wheels of a transfer device used in an automobile having a four-wheel drive function.

[Prior Art] As a prior art of this type of dog clutch, as shown in Utility Model Application No. 53-12131, the dog clutch is energized by a first drive shaft for driving two specific wheels (rear wheels). A sleeve that can move forward and backward in the direction of the rotating axis and an inner end of a second drive shaft for driving the other two wheels (front wheels) are arranged close to each other so that their axes coincide with each other, and the inner end of the sleeve A plurality of internal teeth provided around the circumference and a plurality of external teeth provided to form a spline on the outer periphery of the inner end of the second drive shaft are engaged and disengaged by forward and backward movement of the sleeve. Therefore, some vehicles are designed to allow selection between a two-wheel drive state and a four-wheel drive state. However, in such a dog clutch,
As shown in FIG. 1, the inner teeth b of the sleeve a...
and the meshing side ends of the external teeth d of the second drive shaft c are provided with pointed chamfer parts e..., f..., respectively, and these chamfer parts e..., f... Generally, the guiding action of the internal teeth b... and the external teeth d... facilitates the operation when the internal teeth b... and the external teeth d... are engaged.

[Problems to be Solved by the Invention] However, with such a configuration, a problem arises when switching from two-wheel drive to four-wheel drive while the vehicle is running. In other words, when a vehicle is running in two-wheel drive, there is a difference between the radius of the front wheels and the radius of the rear wheels due to differences in air pressure, unbalanced loads, etc., and the rotational speed of the front wheels changes. but,
The rotation speed of the rear wheels may differ. In other words, when the sleeve a, which rotates together with the rear wheels, is separated from the second drive shaft c, which rotates together with the front wheels, a difference in rotational speed occurs between the sleeve a and the drive shaft c. There is. Therefore, in this state, even if the sleeve a is moved forward in the direction of the drive shaft c to cause the internal teeth b to mesh with the external teeth d, the tip of the channel part e of each internal tooth b is Not only does the interference between the external tooth d and the tip of the chamfer part f of each external tooth d cause an abnormal noise, but also
The sleeve a is caused by the repulsive force generated each time the tips of the channel portions e..., f... interfere with each other.
There is an inconvenience that the progress of
There is a problem in that it is not possible to smoothly switch from wheel drive to four-wheel drive.

The present invention has been made in view of these circumstances, and aims to solve the above-mentioned problems by structurally reducing the frequency of collision and repulsion between the chamfer parts.

[Means for Solving the Problems] In order to achieve such objects, the present invention has the following features:
The following measures were taken. That is,
A dog clutch for switching between two wheels and four wheels of a transfer device according to the present invention includes a sleeve that can move forward and backward in an axial direction that rotates under pressure from a first drive shaft for driving two specific wheels; A plurality of internal teeth provided on the inner periphery of the sleeve and the inner end of the second drive shaft for driving the two wheels of the sleeve are arranged close to each other with their axes aligned with each other. In a device that can be engaged with and disengaged from a plurality of external teeth provided to form a spline on the outer periphery of the inner end of the shaft by advancing and retreating movement of the sleeve, every two teeth have specific teeth that are present at equal pitches. Only the meshing side end portion of the internal tooth extends in a direction closer to the end surface of the opposing external tooth than the meshing side end surface of the other internal teeth, and the extending portion is made into a pointed chamfer portion, and 2 Only the meshing side ends of specific external teeth, which are present at equal pitches in every other book, are extended in a direction closer to the end surface of the opposing internal teeth than the meshing side end surfaces of other external teeth, and the extending portion is placed first. It is characterized by a pointed chianghua part.

[Function] With this structure, the tip of the chimney part of the internal tooth and the tip of the chimney part of the external tooth will less likely interfere with each other and repel each other, allowing the sleeve to move forward appropriately and connect the internal and external teeth. It becomes possible to engage the teeth. In other words, if each engraving pitch of internal teeth and external teeth is p, then in the conventional device shown in FIG. 1, a sleeve with internal teeth and a second sleeve with external teeth
Each time the drive shaft rotates relative to the drive shaft by an angle corresponding to one pitch (p), the tips of the chamfer portions of the internal teeth and the tips of the chamfer portions of the external teeth collide and repel each other. On the other hand,
In the present invention, the chamfer portions of the internal teeth and the chimney portions of the external teeth, which are both extended at equal pitches, are rotated every time the sleeve and the second drive shaft rotate relative to each other by three pitches (3p). The possibility of a collision only arises. Therefore, the possibility of collision and repulsion between the chamfer parts of the internal teeth and the chimney parts of the external teeth is reduced to 1/3 compared to the conventional one. Therefore, there is a high probability that the internal teeth will successfully mesh with the external teeth during the gap where both the channel parts meet each other. Furthermore, even if the chimney part of a specific internal tooth and the chamfer part of a specific external tooth collide and temporarily repel while the sleeve is being advanced in the meshing direction, the sleeve part cannot be moved forward again. Eventually, no collision between the chamfer parts will occur after the relative rotation of one pitch after the collision. Therefore, the sleeve can be advanced beyond the forward position where the chamfer parts collide with each other. Furthermore, from the collision 2
Since the chamfer parts do not collide with each other even when they are rotated relative to each other by the pitch, it is possible to advance the sleeve deeper. Therefore, there is a very high possibility that the inner teeth will be able to mesh with the outer teeth before the chamfer parts collide again after relative rotation by three pitches.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 2 to 5.

A first drive shaft for driving a specific wheel, for example a rear wheel, via a high-speed transmission line 2 or a low-speed transmission line 3 with the rotational force of an input shaft 1 connected to the engine via a transmission. The signal is transmitted to the rear drive shaft 4. Specifically, the input shaft 1
A drive ring 5 is integrally rotatably mounted on the outer periphery of the input shaft 1, and the drive ring 5 of the input shaft 1
A high-speed drive gear 6 and a low-speed drive gear 7 are rotatably mounted at positions sandwiching the same. A spline 5a is formed on the outer periphery of the drive ring 5, and splines 6a and 7a are respectively provided on the drive gears 6 and 7 at portions adjacent to the drive ring 5, so that the splines 5a can be freely slid in the axial direction. The meshed high-speed/low-speed switching shift sleeve 8 can be selectively engaged with either of the splines 6a, 7a.
Further, an idle shaft 9 is rotatably provided between the input shaft 1 and the rear drive shaft 4, and idle gears 11 and 12 are fixedly provided to the idle shaft 9 so as to constantly mesh with the drive gears 6 and 7. , one idle gear 11 is meshed with a driven gear 13 fixed to the rear drive shaft 4. Therefore, when the shift sleeve 8 is engaged with the spline 6a of the high-speed drive gear 6, the rotational force of the input shaft 1 is transferred to the high-speed drive gear 6, the idle gear 11,
The transmission is transmitted to the rear drive shaft 4 via the high-speed transmission line 2 constituted by the driven gear 13, and the shift sleeve 8 is connected to the low-speed drive gear 7.
When the input shaft 1 is engaged with the spline 7a of and is transmitted to the rear drive shaft 4. Note that 14 is a fork for transmitting the operating force of a control lever (not shown) to the shift sleeve 8.

Further, a front drive shaft 16, which is a second drive shaft for driving other wheels, for example, front wheels, is disposed so that its axis coincides with the rear drive shaft 4. Between the inner ends of these drive shafts 4 and 16 are two wheels.
A dog clutch 17 for switching four wheels is provided. The dog clutch 17 is connected to a rear spline 18 provided on the outer periphery of the inner end of the rear drive shaft 4.
, a sleeve 19 that is always engaged with the rear spline 18 so as to be movable in the axial direction, and a front spline 21 provided on the outer periphery of the inner end of the front drive shaft 16. By moving the sleeve 19 forward in the direction of arrow X and engaging it with the front spline 21, a four-wheel drive state is achieved, and by moving the sleeve 19 backward in the direction of arrow Y, the front spline 21
By disengaging the vehicle from the vehicle, a two-wheel drive state is established. And this dog clutch 1
7, among the plurality of internal teeth 22 carved on the inner periphery of the sleeve 19, only the meshing side end of a specific internal tooth 22a is placed forward of the meshing side end surface of the other internal teeth 22b. In other words, it extends in a direction approaching the end surface of the front spline 21, and the extended portion is a pointed chamfer portion 23. Further, a plurality of external teeth 24 constituting the front spline 21
Among them, only the meshing side end of a specific external tooth 24a... is extended backward from the meshing side end surface of the other external teeth 24b, that is, in a direction approaching the end surface of the opposing internal tooth 22. Channel part 2 with a pointed end
5... The specific internal teeth 22a... and the specific external teeth 24a... are equally distributed in the circumferential direction, with one each for every two other internal teeth 22b... and other external teeth 24b. In other words, only the proportion side ends of the specific inner teeth 22a, which are present at the same pitch every two, are extended in a direction closer to the end surfaces of the opposing outer teeth 24 than to the meshing side end surfaces of the other internal teeth 22b. The extended portion is connected to the pointed chimney portion 23...
At the same time, only the meshing end portions of the specific external teeth 24a, which are present at the same pitch every two teeth, are moved in a direction closer to the end surface of the opposing internal tooth 22 than the meshing end surface of the other external teeth 24b. The extended portion is made into a pointed chamfer portion 25. In addition,
26 is a fork for transmitting the operating force of a control lever (not shown) to the sleeve 19.

With such a configuration, it is possible to switch between two-wheel drive and four-wheel drive by the same operation as in conventional systems, but in the present invention, the internal teeth of the sleeve to be engaged and disengaged are All of the external teeth of the front drive shaft are no longer provided with a chamfer part, and every second specific internal tooth 22a... and every second specific external tooth is made to extend more than the other teeth on the meshing side. 24a... only the channel part 23
..., 25..., the above-mentioned conventional disadvantages can be effectively suppressed. In other words, in the conventional system, when there is a difference in rotational speed between the sleeve and the front drive shaft, when the inner teeth of the sleeve are moved closer to the outer teeth of the drive shaft, the chamfer of the inner teeth increases for each tooth. Since the tip of the chimney part and the tip of the chamfer part of the external tooth interfere with each other and repel each other, abnormal noise is generated significantly, and the repulsive force that frequently occurs makes it virtually impossible for the sleeve to move forward. On the other hand, if the chamfer parts 23 of the internal teeth 22 and the chamfer parts 25 of the external teeth 24 are provided extending every second as in the present invention, the chamfer parts of the internal teeth 22a can be provided. The tip of 23... and the chamfer part 25 of the external tooth 24a...
It is possible to reliably reduce the frequency of interference and repulsion between the tips of... Therefore, it is possible to increase the probability that the internal teeth 22 will mesh successfully with the external teeth 24 without the gap where the channel portions 23, 25, etc. meet each other. Moreover, since the internal teeth 22... and the external teeth 24... are extended every two teeth, in other words, the specific internal teeth 22a... that are extended and the specific external teeth 24a that are extended.
... is provided at a pitch (3p) that is three times the engraving pitch (p) of the internal teeth 22 ... and the external teeth 24 ..., so even if the chamfer portion 23 ... of a specific internal tooth 22a ... is extended... and a specific external tooth 24a that is extended.
Even if the chamfer parts 25 of ... collide and repel, the probability that the meshing can be completed immediately afterward can be reliably increased. That is, the sleeve 19
Even if the chamfer parts 23 of the specific internal teeth 22a and the chamfer parts 25 of the specific external teeth 24a collide with each other and temporarily repel while advancing the sleeve in the meshing direction, the sleeve will not move again. 19, when the chain parts 23..., 25... have made a relative rotation of one pitch (p) after the collision, the chain members 23..., 25...
There will be no conflict between comrades. Therefore, the sleeve 19 can be advanced beyond the forward position where the chamfer parts 23..., 25... collide with each other. Furthermore, even after the relative rotation of 2 pitches (2p) after the collision, the channel portion 2
3..., 25... Since no collision occurs, it becomes possible to advance the sleeve 19 deeper.
Therefore, there is a very low possibility that the inner teeth 22a can be brought into mesh with the outer teeth 24 before the chamfer parts 23..., 25... collide again after relative rotation by 3 pitches (3p). It will be expensive.

In the above embodiment, the first drive shaft drives the rear wheels and the second drive shaft drives the front wheels. However, conversely, the first drive shaft drives the front wheels. The rear wheels may be driven by a second drive shaft.

[Effects of the Invention] Since the present invention has the configuration as described above, it is possible to successfully mesh the internal teeth and external teeth without the interval in which the chimney portions of the internal teeth and the chimney portions of the external teeth collide and repel. Furthermore, even if the chamfer parts collide with each other and repel each other, it is possible to reliably increase the possibility that the meshing can be completed before the next collision occurs. Therefore, even under driving conditions where there is a difference in rotational speed between the front wheels and the rear wheels, it is possible to switch from two-wheel drive to four-wheel drive relatively smoothly without causing abnormal temperatures. Accordingly, it is possible to provide a dog clutch for switching between two wheels and four wheels for a transfer device.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a conventional example, FIG. 2 is a sectional view showing an embodiment of the present invention, FIG. 3 is a partially omitted view along the - line in FIG. 2, and FIG.
The figure is a partially omitted view taken along the - line in FIG. 2, and FIG. 5 is a developed view taken along the line - in FIG. 3. 4... First drive shaft (rear drive shaft), 16... Second drive shaft (front drive shaft), 17... Dog clutch, 19... Sleeve, 22... Internal teeth, 22
a...Specific internal tooth, 22b...Other internal teeth, 23...
. . . Channel portion, 24 . . . External teeth, 24a . . . Specific external teeth, 24b .

Claims (1)

[Claims] 1 A sleeve that can move forward and backward in the axial direction and rotates under the influence of a first drive shaft for driving two specific wheels, and a second sleeve that drives two other wheels.
and the inner end of the second drive shaft are arranged close to each other so that their axes coincide with each other, and a plurality of internal teeth provided on the inner periphery of the sleeve and a spline are provided on the outer periphery of the inner end of the second drive shaft. In a dog clutch for two-wheel/four-wheel switching, which is capable of engaging and disengaging a plurality of external teeth provided to form a plurality of external teeth by advancing and retracting movement of the sleeve, certain internal teeth exist at an equal pitch every other two wheels. Only the meshing side end of the tooth extends in a direction closer to the end surface of the opposing external tooth than the meshing side end surface of the other internal teeth, and the extension part is made into a pointed chamfer part, and every second Only the meshing side ends of specific external teeth that are present at equal pitches are extended in a direction closer to the end surface of the opposing internal teeth than the meshing side end surfaces of other external teeth, and the extending portion is A dog clutch for switching between two wheels and four wheels for a transfer device, characterized by having a vertical chamfer part.