Hydraulic machine comprising a stack of discs acted on by a push rod
The hydraulic machine comprises: —a fixed part, —a part mounted so as to rotate about an axis (O-O) with respect to the fixed part, —a stack ( 50 ) of discs ( 53, 54 ) forming a brake or clutch, the discs being able to be in abutment against one another by way of friction surfaces ( 88 ) having a mean friction radius (Rf) with respect to the axis, —a push rod ( 80 ) that is able to push the discs into abutment against one another, in a direction parallel to the axis, over a thrust surface ( 4 ), the thrust surface having a mean thrust radius (Rp) with respect to the axis which extends to within or beyond the mean friction radius (Rf). The push rod ( 80 ) has a radial annular notch ( 90 ) indenting the push rod from an opposite side of the push rod from the axis (O-O) when the mean thrust radius (Rp) extends beyond the mean friction radius (Rf), and otherwise from the side of the push rod closest to the axis.
1 . A hydraulic machine,
the hydraulic machine comprising:
a fixed part,
a part rotatably mounted about an axis with respect to the fixed part,
a stack of disks forming a brake or clutch, the disks being configured to be in abutment against one another by way of friction surfaces having a mean friction radius measured from the axis; and
a push rod configured to push the disks into abutment against one another, in a direction parallel to the axis, over a thrust surface having a mean thrust radius measured from the axis and which extends beyond the mean friction radius, the push rod having a radial annular notch indenting the push rod from a side of the push rod opposite to the axis;
wherein the notch is dimensioned so that the mean friction radius is comprised between a larger radius of the notch and a smaller radius of the notch.
2 . The machine according to the preceding claim , wherein the push rod has a radius greater than a larger radius of the friction surfaces.
3 . The machine according to claim 1 , configured so that at least one part of the push rod bends increasingly as thrust of the push rod against the stack increases.
4 . The machine according to claim 1 , wherein at least one part of the push rod has an axial dimension which decreases in the direction of a free end of the at least one part of the push rod.
5 . The machine according to claim 1 wherein, the notch having two main faces facing one another, one of these faces is inclined oriented in the direction of the exterior of the push rod.
6 . The machine according to claim 5 wherein the inclined face extends from one side of the notch closest to the stack.
7 . The machine according to claim 1 , wherein the push rod has a push rod guide face in the axial direction with respect to a support.
8 . The machine according to the preceding claim wherein the guide face extends entirely from one side of the notch farthest away from the stack.
9 . The machine according to claim 1 , which comprises:
a spring configured to push the push rod against the stack, and
a de-braking chamber configured so that hydraulic pressure in the chamber applies a force opposing braking to the spring.
10 . The machine according to claim 1 , wherein the stack is in an oil bath.
11 . The machine according to claim 1 , wherein the disks are made of nitrided steel.
12 . The machine according to claim 1 , wherein the disks comprise a lining of a friction material.
13 . The machine according to the preceding claim , wherein the lining has grooves.
14 . The machine according to claim 1 , wherein the stack forms a brake.
15 . A hydraulic machine,
the hydraulic machine comprising:
a fixed part,
a part rotatably mounted about an axis with respect to the fixed part,
a stack of disks forming a brake or clutch, the disks being configured to be in abutment against one another by way of friction surfaces having a mean friction radius measured from the axis; and
a push rod configured to push the disks into abutment against one another, in a direction parallel to the axis, over a thrust surface having a mean thrust radius measured from the axis and which extends within the mean friction radius,
the push rod having a radial annular notch indenting the push rod from a side of the push rod closest to the axis,
wherein the notch is dimensioned so that the mean friction radius is comprised between a larger radius of the notch and a smaller radius of the notch.