Patent Description:
In automobiles, in the field of manual transmission, there are friction clutches positioned between the motor outlet of the combustion engine and the transmission shaft and which provide power transmission to the gearbox by means of friction link.

In manual transmission, the friction clutch generally comprises a cover fixed to the flywheel of the combustion engine, a plate linked in rotation with the cover and able to rub against a clutch disc. The friction clutch also comprises a diaphragm spring, which is of the Belleville type, said diaphragm spring is interposed axially between the cover and the plate and is able to press the plate onto the clutch disk.

In said friction clutches, ventilation channels are used onto the plate in order to eliminate the heat which occurs as a result of friction. The heat convection performances of said ventilation channels are tried to be increased in an effective manner as much as possible. The channels, formed for increasing heat transfer performance, lead to decrease of the explosion resistance of the related plate. Thus, a balance must be formed between the resistance of the plate and the cooling performance.

In the publication with number <CIT>, a plate for friction clutches is disclosed.

The ventilation channels provided on said plate are provided in curved form from the inner wall of the plate towards the outer wall and in different directions in a manner interrupting each other. Thus, cooling performance of the plate is improved by increasing air circulation in the ventilation channels. Documents <CIT> , <CIT> and <CIT>U show other examples of plates for friction clutches.

The present invention relates to a plate for friction clutches, for eliminating the above mentioned disadvantages and for bringing new advantages to the related technical field.

An object of the present invention is to provide a plate with increased cooling performance for friction clutches.

In order to realize all of the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention is a plate for use in a transmission member which provides movement transfer between the motor and the gear box in motorized vehicles, the subject matter plate comprising an annular body with a rotation axis delimited by a cylindrical inner wall and a cylindrical outer wall, and a friction surface and at least one ventilation channel extending radially from said cylindrical inner wall towards the cylindrical outer wall. According to the invention, a channel height in the axial direction, defined between a first wall of said ventilation channel and a second wall of the ventilation channel arranged axially opposite to the first wall, is provided in a form which firstly widens and afterwards narrows from the cylindrical inner wall towards the cylindrical outer wall.

According to the invention, said second wall is provided in the vicinity of said friction face where friction occurs on the plate.

According to the invention, at least one of the first wall and the second wall is provided in arc shape.

In a preferred embodiment of the invention, at least one of the first wall and the second wall is provided in concave form.

In a preferred embodiment of the invention, both of the first wall and the second wall are provided in concave form.

In a preferred embodiment of the invention, the diameter of the concave form of the second wall which is adjacent to the friction surface is smaller than the diameter of the concave form of the first wall.

In a preferred embodiment of the invention, a first channel height, defined at the side of the ventilation channel which is close to the inner wall, is greater than a second channel height defined at the side of the ventilation channel which is close to the outer wall.

In a preferred embodiment of the invention, the proportion of the first channel height to a maximum channel height, which defines the maximum height of the ventilation channel, is between <NUM> and <NUM>.

In a preferred embodiment of the invention, the proportion of the first channel height to a maximum channel height, which defines the maximum height of the ventilation channel, is <NUM>.

In a preferred embodiment of the invention, the proportion of the second channel height to a maximum channel height, which defines the maximum height of the ventilation channel, is between <NUM> and <NUM>.

In a preferred embodiment of the invention, the proportion of the second channel height to the maximum channel height is <NUM>.

In a preferred embodiment of the invention, in a plane perpendicular to the axis crossing the ventilation channel, the ventilation channel is provided in a curved manner from the cylindrical inner wall towards the cylindrical outer wall.

In a preferred embodiment of the invention, in a plane perpendicular to the axis crossing the ventilation channel, the ventilation channel is provided in a straight manner from the cylindrical inner wall towards the cylindrical outer wall.

In a preferred embodiment of the invention, in a plane perpendicular to the rotation axis crossing the ventilation channel, the ventilation channel is embodied in a manner having a channel width which increases from the cylindrical inner wall towards the cylindrical outer wall.

In a preferred embodiment of the invention, the plate is using cast iron material, for example Solid Solution Strengthened Ferritic Ductile Iron according to the European Standard EN <NUM>.

In a preferred embodiment of the invention, a plate incorporating all or part of the characteristics mentioned above is an inertia plate, said inertia plate comprising a bearing face arranged to press on a crankshaft of an internal combustion engine and a series of holes distributed angularly to the axis of rotation, the holes being arranged to allow fixing screws to pass.

A second object of the invention is a friction clutch comprising a cover, a diaphragm spring mounted inside of the cover and a plate incorporating all or part of the preceding characteristics, said plate comprising a circular support for providing linear contact with the diaphragm spring. The circular support can be continuous or discontinuous.

In a preferred embodiment of the invention, an added ring is provided between the cover and the diaphragm spring.

In this detailed description, the subject matter plate <NUM> is explained with references to examples without forming any restrictive effect only in order to make the subject more understandable.

In motorized vehicles, transmission members are used for providing movement transfer between the motor and the gearbox Said transmission member can be a friction clutch, a flywheel or a tractor cover.

On said transmission members, the subject matter plate <NUM> is used. Said plate <NUM> essentially has a circular body <NUM>. Said circular body <NUM> rotates in a rotation axis X A face of the circular body <NUM> is defined as a friction face <NUM>. Moreover, the circular body <NUM> has a cylindrical inner wall <NUM> and a cylindrical outer wall <NUM>. There is at least one ventilation channel <NUM> for providing decreasing of the heat formed due to the friction which occurs on the friction face <NUM>. Said ventilation channel <NUM> extends from the cylindrical inner wall <NUM> towards the cylindrical outer wall <NUM>. In the subject matter plate <NUM>; a channel height H which defines the height of the ventilation channel <NUM> in the rotation axis is provided in a form which firstly widens and which afterwards narrows towards the cylindrical outer wall <NUM>. In other words, the ventilation channel <NUM> has a first wall <NUM> and a second wall <NUM> provided opposite to the first wall <NUM> in the direction of the rotation axis X Said second wall <NUM> is provided in the vicinity of the friction face <NUM>. According to the present invention, at least one of the first wall <NUM> and the second wall <NUM> is provided in an arc form. In other words, at least one first wall <NUM> and the second wall <NUM> is provided in concave form. Thus, the channel height H of the ventilation channel <NUM> firstly widens and afterwards narrows from the cylindrical inner wall <NUM> towards the cylindrical outer wall <NUM>. In other words, the ventilation channel <NUM> has a cross section which is similar to an airplane-wing. In a possible embodiment of the present invention, both of the first wall <NUM> and the second wall <NUM> are provided in concave form.

Thanks to said cross section of the ventilation channel <NUM>, the speed of air which passes through the ventilation channel <NUM> is increased regionally. In other words, the concave form of the first wall <NUM> and/or of the second wall <NUM> provides more rapid movement of air in this region. Thus, in these parts, heat convection performance is increased.

As can be seen in <FIG>, the heat convection performance which occurs depending on the rotation speed of the subject matter plate <NUM> becomes better when compared with plates without channels and when compared with the prior art. In other words, since the channel height is fixed in the prior art, regional speed change effect does not occur in the channel. In the subject matter plate, the change in the channel height leads to regional speed change and increase in the heat convection performance.

As can be seen in <FIG>, the stress value which occurs depending on the rotation speed is observed as minimum at the plates without channel. In other words, the explosion resistance under centrifugation of the plates without channel is higher. The explosion resistance of the subject matter plate (<NUM>) becomes better when compared with the prior art and approaches the explosion resistance of plates without channel.

Thus, by means of the subject matter plate <NUM>, the explosion resistance can be kept at a sufficiently high level and at the same time, the cooling performance can be increased. Since the explosion resistance is higher when compared with the prior art, this shows that a lighter plate <NUM> which can be produced with less material can show the same explosion resistance and can have better cooling performance.

In a possible embodiment of the present invention, the curve diameter of the second wall <NUM> which is adjacent to the friction face <NUM> is provided to be smaller than the diameter of the first wall <NUM>. Thus, the path, along which the air must move, at the second wall <NUM> side is greater and the air moves in a more rapid manner. Thus, at the friction face <NUM> side, in other words, at the part where heat occurs, a more effective cooling can be provided.

In another possible embodiment of the present invention, the height of the side of the ventilation channel <NUM> which is close to the cylindrical inner wall <NUM> is defined as a first channel height H1 and the height of the side which is close to the cylindrical outer wall <NUM> is defined as a second channel height H2. In said embodiment, the first channel height H1 is greater than the second channel height H2. Thus, air hits to the first wall <NUM> and to the second wall <NUM> and changes direction and the heat convection performance is increased.

In a possible embodiment of the present invention, the proportion of the first channel height H1 to a maximum channel height Hmax defined at the widest place of the ventilation channel <NUM> is between <NUM> and <NUM>. In a possible embodiment of the present invention, it is <NUM>.

In a possible embodiment of the present invention, the proportion of the second channel height H2 to the maximum channel height Hmax is between <NUM> and <NUM>. In a possible embodiment of the present invention, it is <NUM>.

In a possible embodiment of the present invention, at an orthogonal plane in the rotation axis X which passes through the ventilation channel <NUM>, the ventilation channel <NUM> is provided in a curved form from the cylindrical inner wall <NUM> towards the cylindrical outer wall <NUM>. Thus, heat convection performance is increased by providing guidance of air in the ventilation channel <NUM>.

In another possible embodiment of the present invention, at an orthogonal plane in the rotation axis X which passes through the ventilation channel <NUM>, the ventilation channel <NUM> is embodied to have a channel width L which increases from the cylindrical inner wall <NUM> towards the cylindrical outer wall <NUM>.

As can be seen in <FIG>, the subject matter plate is provided as the component of a flywheel. The plate of said flywheel is provided in a circular form. There are ventilation channels between the cylindrical innerwall and the cylindrical outer wall of the circular plate.

As can be seen in <FIG>, the subject matter plate is provided as a component of a tractor cover. The plate of said tractor cover has a circular body whereon fingers are positioned. There are ventilation channels between the cylindrical inner wall and the cylindrical outer wall of the circular plate.

As can be seen in <FIG>, the subject matter plate is provided as a component of a friction clutch. <FIG> shows a friction clutch <NUM> comprising a cover <NUM> and a diaphragm spring <NUM> centered on the cover. The diaphragm spring bears onto a ring added onto a connecting zone of the cover. The cover can be attached by suitable fixing means to a flywheel or momentum wheel (not depicted), itself mounted on the output shaft of an engine, for example of the internal combustion engine type (not depicted).

The friction clutch <NUM> also comprises a plate <NUM>, also called pressure plate, designed to come to bear against a clutch disc (not depicted). The plate <NUM> comprises a circular support <NUM> for providing linear contact with the diaphragm spring <NUM>. This circular support <NUM> can be continuous or discontinuous.

During the disengaging and engaging of said friction disc <NUM>, heat is created since friction occurs between the friction surface <NUM> of the plate <NUM> and the clutch disc. Since the heat, occurring as a result of the relative movement between the disc friction lining surface and the plate <NUM> according to the invention which is in contact therewith, will lead to temperature increase in the pressure plate. In order to evacuate the heat from the plate <NUM>, the second wall <NUM> of the ventilation channel <NUM> is provided in the vicinity of the friction face <NUM>. The distance separating the second wall <NUM> to the friction surface <NUM> is comprised between <NUM> to <NUM>.

Claim 1:
A plate (<NUM>) for use in a transmission member which provides movement transfer between the motor and the gear box in motorized vehicles, the subject matter plate (<NUM>) comprising an annular body (<NUM>) with a rotation axis (X) delimited by a cylindrical inner wall (<NUM>) and an cylindrical outer wall (<NUM>), and a friction surface (<NUM>) and at least one ventilation channel (<NUM>) extending radially from said cylindrical inner wall (<NUM>) towards the cylindrical outer wall (<NUM>), wherein a channel height (H) in the axial direction, defined between a first wall (<NUM>) of said ventilation channel (<NUM>) and a second wall (<NUM>) of the ventilation channel (<NUM>) arranged axially opposite to the first wall (<NUM>), is provided in a form which firstly widens and afterwards narrows from the cylindrical inner wall (<NUM>) towards the cylindrical outer wall (<NUM>),
wherein said second wall (<NUM>) is provided in the vicinity of said friction face (<NUM>) where friction occurs on the plate (<NUM>,
characterized in that at least one of the first wall (<NUM>) and the second wall (<NUM>) is provided in arc shape.