JPH0819978B2 - Liquid friction clutch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid friction clutch comprising at least 1
One clutch hub and one clutch casing rotatably supported on the clutch hub. The clutch hub and the clutch casing are alternately provided with a plurality of plates in a fixed order via engagement teeth extending in the radial direction. The plates of the set are non-rotatably connected, the plates of one plate set are axially spaced from one another, and the plates of the other plate set are axially slidable. Regarding the format.

[Conventional technology]

In the case of a liquid friction clutch of this kind known, for example, from German patent DE 3828421 C1, so-called spacer rings of a certain thickness are used to keep the plates apart. The spacer ring is slit and has an outer diameter slightly larger than the inner diameter of the clutch casing so that it can contact the inner wall of the casing with initial tension. However, a drawback is that automatic assembly of the plates is not possible and, if possible, is very expensive. Therefore, the individual plates are assembled manually.

According to U.S. Pat. No. 3,580,027 it is known to bend some teeth of the plate to provide an elastic return action. However, such bending is inconvenient for maintaining the distance between the plates. This is because the tolerance of the outer diameter of each plate and especially the centering of the plates must be very strict in order to obtain a uniform spacing accuracy, but the bending of the teeth makes it impossible to maintain such tolerance due to the return force. Either impossible or possible only at significant cost. According to West German Patent No. 3726641C1, it is known to provide one plate set with a cam-shaped deformable portion. These deformations are oriented in one direction of rotation and thus produce a corresponding increase in the spacing of the associated plates.

However, such a treatment is intended to give the liquid friction clutch a difference in torque characteristics in both rotation directions in the first place, and cannot maintain a predetermined distance between the plates.

[Problems to be Solved by the Invention]

The object of the present invention is to eliminate the conventionally used spacer rings in a liquid friction clutch of the type mentioned at the outset, while still allowing a satisfactory spacing between the plates.

[Means for solving the problem]

The present invention has solved such a problem as follows.
That is, a predetermined number of the engaging teeth of each plate that does not slide in the axial direction form a space-maintaining tooth that is bent out of the plane of the plate in an O-shape, and both of the two teeth are folded. The bending angle is almost 90 °.

According to such a procedure, the plate for the liquid friction clutch can be assembled so as to be accurately held at a predetermined interval. Such a plate according to the invention is suitable for automatic assembly, in which case either the inner plate or the outer plate can be provided with B-shaped spacing teeth according to the function to be set. Since the B-shaped bend has a bending angle of almost 90 °, the accuracy of bending in the axial direction depends only on the accuracy of the tool used.
Therefore, other tolerances such as plate outer diameter, inner diameter or material thickness do not affect the dimensional accuracy of the bend. Another advantage of folding the spacing tooth according to the invention is that no bending moment acts on the spacing tooth folded in the O-shape. The axial force acting on the spacing folds may only act as a pushing force in the axial web.

In the case of an advantageous embodiment in which a particularly simple assembly is possible, a certain number of engaging teeth of the outer plate, which is connected to the clutch casing in a non-rotatable manner, form spacing teeth that are bent in a V shape. .

In the case of a liquid friction clutch configured as a so-called torque split device, two sets of inner plates are used, and the engagement teeth of the pressing constant of the inner plate that are non-rotatably coupled to at least one clutch hub are used. It has spacing teeth that are bent in the shape of a second letter.

〔Example〕

FIG. 1 schematically shows the drive system of a four-wheel drive vehicle 15. The vehicle 15 is normally front-wheel drive.
Both front wheels 16 are driven by a prime mover 18 via a main transmission 19 and a front axle differential 20 and side shafts 21. A drive system for the rear wheels 17 branches from the front axle differential device 20. For this reason, the center differential 22 is attached to the front differential 20. The center differential 22 is provided with a single liquid friction clutch as shown in FIG. 2, which provides a differential limiting action related to the rotation speed of the center differential 22. The center differential device 22 is connected to a rear axle differential device 24 via a propeller shaft 23, and the rear axle differential device 24 drives the rear wheels 17 via a side shaft 25.

The liquid friction clutch shown in FIG. 2 mainly comprises a clutch hub 1 and a clutch casing 2 which is rotatably supported on the clutch hub 1 by a seal member 3. The inner wall of the clutch casing 2 has internal teeth 4, whereas the clutch hub 1 has external teeth 5. A large number of inner plates 6 having teeth on the inner periphery thereof are fitted to the outer teeth 5 so as not to be rotatable and movable in the axial direction. A large number of outer plates 7 having engagement teeth 9 extending radially corresponding to the outer periphery via the inner teeth 4.
Is non-rotatably held by the clutch casing 2.

A large number of inner plates 6 and outer plates 7 are alternately arranged in a fixed order in the inner chamber 11 of the clutch casing 2. In this case, some of the engaging teeth 9 of the outer plate 7 are adjacent to each other. In order to maintain the space between the two, the space-maintaining teeth 8 are bent in the shape of a second letter. A space 12 is formed between the inner plate 6 and the outer plate 7, and the inner plate 6 slides in the space 12 in the axial direction. On the other hand, each outer plate 7 is kept at a constant interval by the spacing holding teeth 8 that are bent in the shape of a double letter. The space-maintaining teeth 8 that are bent in a B-shape are in contact with the unfolded engaging teeth 9 of the outer plates 7 that are adjacent to each other.

As shown in FIG. 3, the space-maintaining teeth 8 that are bent in the O-shape are bent out of the plane of the outer plate 7 by the right-angled portions 14. After forming the axial web 13 of a length related to the desired spacing, it is further bent in the direction parallel to the plane of the outer plate 7 by the right angle portion 14a. This ensures that the axial web 13 is at right angles to the plane of the outer plate 7 and is not subject to bending moments when it is spaced apart from its adjacent outer plates.

In the case of the embodiment of the outer plate 7 shown in FIG. 4, five spacing teeth 8 bent in the shape of a letter B are provided. The number of such spacing teeth 8 is arbitrary in relation to the pitch of the external teeth, but at least three must be provided for the desired effect. The outer plate 7 has many slits 10 on the inner peripheral side. When the outer plate 7 is assembled, the space-maintaining teeth 8 that are bent in a V shape.
Must contact the unfolded teeth of adjacent outer plates, respectively. Such positioning can be done, for example, by providing index marks along the plate and providing the automatic feeder with appropriate means.

As shown in FIG. 5, the folded spacing teeth 8 allow the spacing to be maintained by the web 13 in the axial direction, and this spacing can be provided with sufficient accuracy. Outer plate 7 kept at such intervals
The liquid friction clutch having the above can be incorporated in a center differential 22 of an automobile as shown in FIG. 1, for example. In the illustrated embodiment, the clutch hub 1 is the driving part and the clutch casing 2 is the driven part, which is connected to the rear axle differential 24 via the propeller shaft 23. A viscous medium, in particular silicone oil, is at least partially enclosed in the internal chamber of the clutch casing 2.

FIG. 6 shows an example in which the inner plate 6 has the spacing holding teeth 8a which are bent in the shape of a second letter.

FIG. 7 schematically shows a drive system of an automobile in which a so-called torque split device 28 is used instead of the center differential device 22 described above. This torque split device 28 is the same as the center differential device 22 at the same time as the usual rear axle differential device.
Take the place of 24. The torque split device 28 includes a casing 26 driven by a bevel gear mechanism 27, a casing 26 in which a pair of outer plates are mounted so that they cannot rotate relative to each other, and two sets of inner plates belonging to each rear wheel drive unit. And consists of. The present invention can be applied particularly effectively to such applications. This is because a large number of plates are used in such cases and automatic assembly of the plates is effective.

[Brief description of drawings]

FIG. 1 is a schematic view of a drive system of a four-wheel drive vehicle incorporating a liquid friction clutch, FIG. 2 is a partial vertical cross-sectional view of the liquid friction clutch of the present invention, and FIG. 3 is an outer plate bent into a V shape. FIG. 4 is an enlarged view of the spacing teeth, FIG. 4 is a plan view of the outer plate, FIG. 5 is a side view of the outer plate, and FIG. 6 is a plan view of an inner plate having spacing teeth bent in a B shape. The figure is a schematic diagram showing a drive system of a four-wheel drive vehicle provided with a torque split device. 1 ... Clutch hub, 2 ... Clutch casing, 3 ... Seal member, 4 ... Inner teeth, 5 ... Outer teeth, 6 ... Inner plate, 7 ... Outer plate, 8 ... B-shaped bent Space maintaining teeth, 9 ... Outer plate engaging teeth, 10 ... Slit, 11 ... Internal chamber, 12 ... Air gap, 13 ... Axial web, 14 ... Right angle part, 15 ... Automobile, 16 …… Front wheel, 17 …… Rear wheel, 18 …… Motor, 19 …… Main transmission, 20 …… Front shaft differential, 21 …… Side shaft, 22 …… Center differential, 23 …… Propeller shaft , 24 …… rear axle differential, 25 …… side shaft, 26 …… casing, 27 …… bevel gear mechanism, 28 …… torque split device.

Claims (3)

[Claims] 1. A liquid friction clutch comprising at least 1.
One clutch hub and one clutch casing rotatably supported on the clutch hub. The clutch hub and the clutch casing are alternately provided with a plurality of plates in a fixed order via engagement teeth extending in the radial direction. The plates of one plate set are axially spaced from each other and the plates of the other plate set are axially slidable. A plurality of engaging teeth of each plate (7) which does not slide in the axial direction, a predetermined number of teeth forming a space-maintaining tooth (8) bent out of the plane of the plate in a B-shape. The liquid friction clutch is characterized in that the bending angles (14, 14a) at both of the two places are approximately 90 °. 2. An interval holding tooth (8) in which a predetermined number of teeth of an engaging tooth of an outer plate (7) which is connected to a clutch casing (2) so as not to be rotatable relative to each other, are bent in a B-shape. The liquid friction clutch according to claim 1, wherein: 3. A spacing tooth (3) in which a predetermined number of teeth of an engaging tooth of an inner plate (6) which is coupled to at least one clutch hub (1) so as not to be rotatable relative to each other are bent in an O shape. The liquid friction clutch according to claim 1, which is in the form of 8a).