FR2753401A1 - FRICTION LINING RIVETING SYSTEM ON THEIR SUPPORT DISC - Google Patents

Abstract

The installation has a fixed tool (30) with a force sensor (90) connected to a load monitor (91) to control the stopping of the downward stroke of a jack carrying the mobile tool (40). Clutch friction application.

Description

The present invention relates to a fitting riveting installation

  friction on their associated support disc, in particular for a

  motor vehicle clutch friction.

  As is known, the friction linings of a clutch friction are intended to be clamped between the pressure and reaction plates of a clutch. The two friction linings, usually of annular shape, are

  fixed on a support disc on either side of it.

  The support disc with its friction linings constitutes the input element of the clutch friction. This input element is rigidly or resiliently coupled to an output element, usually in the form of an internally fluted hub for its rotational connection with a driven shaft, namely the shaft.

gearbox input.

  The input element is intended, by means of its friction linings, to be wedged, in a disengageable manner, in rotation on a shaft leading to

  know the crankshaft integral in rotation with the pressure and reaction plates.

  The fittings are fixed to their support conventionally using hollow and shouldered rivets. This is achieved using a so-called fixed tool and a movable counter-tool relative to the fixed tool, the rivet being interposed between said tools. The stationary tool has a mobile pilot centrally. The tools are carried by

a fixed frame.

  The shoulder of the rivet is intended to come into contact with the support disc. The barrel of the rivet passes through holes made in axial coincidence in the disc and the friction lining. The free end of the hole in the friction lining, opposite the end of the hole adjacent to the disc, is widened to form a countersink and a shoulder. The head of the rivet is housed in the counterbore and is opened out in a daisy using the fixed tool in contact with the shoulder formed by the change in diameter of the hole in the friction lining, the movable tool acting

on the shouldered tail of the rivet.

  Thus the lining and the disc are presented, then the pilot with a profiled penetrating head comes out and is introduced into the holes of the lining and of the disc to put said holes in axial coincidence. Above the fixed tool and the disc - friction lining assembly is a vibrating bowl allowing the supply of rivets, a movable needle, carried centrally for the movable tool, makes it possible to lower the rivet into the hole with pilot-shaped retraction

rod with penetrating head.

  Then we lower the mobile tool to proceed with riveting.

  This descent is carried out using an electric motor actuating a rod-crank system making it possible to perform a constant stroke of the mobile tool. This installation is satisfactory. However, it may be desirable to reduce maintenance costs and better control the tightness of the seals. The object of the present invention is to respond to these wishes of

simple and economical way.

  According to the invention a riveting installation of the above-mentioned type is characterized in that the mobile tool is carried by a fluid cylinder, while the fixed tool comprises a force sensor, and in that the force sensor is connected to a load monitor making it possible to control the working stroke of the jack by controlling its stopping from a force determined by the force sensor. Advantageously, the force sensor is of the piezoelectric type and the

  pneumatic and hydraulic cylinder.

  Thanks to the invention as soon as the clamping force is reached

  predetermined at the level of the rivets, the movement of the mobile tool is stopped.

  Thus, the fixing of the friction linings is precisely controlled. Indeed, the clamping force of the rivets will be sufficient to ensure the transmission of the torque in all circumstances. It will not be too high not to

  cause rupture at the friction linings.

  In operation the friction linings will not tear off at the

level of rivets.

  Thanks to the invention one can get rid of any visual control in the end.

  The cost of installation is reduced, as well as maintenance costs.

  The instantaneous management of the applied load allows each riveting for different clutch frictions to overcome all physical parameters. 3 0 Thanks to the quartz crystal sensor, precise measurements are obtained and this with a small footprint. This sensor also has a simple shape in

  being generally annular in shape.

  The load monitor is a measuring, command and control device. In practice, this electronic monitor includes a charge amplifier allowing the force (charge) generated by the sensor to be transformed.

with quartz crystal in tension.

  The monitor also has a control unit which indicates in particular the operating mode of the monitor and controls the amplifier.

charge as well as other units.

  This monitor makes it possible to send an active control signal to the fluid cylinder more precisely to a distributor and to a sequence valve which comprises

said cylinder.

  The control unit allows comparisons to be made.

  Thus, it is possible to display limit values by means of a selector and to carry out using a comparator, receiving the amplified signal from the sensor and the

  value of the displayed signal, a comparison.

  When an overrun occurs, the control signal sent to the

fluid cylinder.

  You can also perform monitoring functions and switch on

  consequence of diodes or an alarm.

  You can also display the sensitivity of the sensor and perform tests.

  For example, using a push button, you can make a brief

  reset the charge amplifier and the peak value memory.

  Using the monitoring function as soon as the signal associated with the sensor becomes lower than a predetermined signal, an alarm is triggered. / 2 o All this is achieved by configuring electronically accordingly

the monitor.

  Thanks to the pneumatic and hydraulic cylinder, called pneumatic cylinder

  hydraulic, the mobile tool can perform an approach stroke using a distributor allowing air to be supplied to a chamber associated with a tool operating piston. A high speed movement can thus be achieved and

  this with a reduced effort until one comes into contact with the rivet.

  The resistance created by the working rivet triggers a so-called sequence valve allowing compressed air to enter the back

  an amplifying piston associated with a hydraulic chamber.

  3 0 A working stroke is then carried out, the operating piston being

subjected to hydraulic pressure.

  As soon as the distributor receives a signal from the monitor the distributor is actuated so that the sequence valve is put on the exhaust with return

  operating and amplification pistons in the starting position.

  It is evident from the above that the installation is little

  expensive and low maintenance cost.

  The description which follows illustrates the invention with reference to the drawings

  attached in which: - Figure 1 is a half view in axial section of a clutch friction; - Figure 2 is a schematic view of the riveting installation according to the invention without the support disc and the friction linings; - Figure 3 is an enlarged view of part of Figure 2; - Figure 4 is a partial view showing the so-called fixed tool; - Figure 5 is a schematic sectional view of the cylinder of the installation. In Figure 1 we see at 20 a clutch friction which, as mentioned above, comprises a support disc 20 of friction linings 21 arranged on either side of the disc 20 belonging to the input element of the clutch friction, the output element of which consists of a hub 23 coupled here by springs 24 to the disc 20. Hollow shouldered rivets 22 fix each lining 21

1_5 to disc 20.

  Each rivet 22, by its tail, constituting the shoulder, bears on the disc 20 and passes through its barrel with holes (not referenced) made in

  axial coincidence in the disc 20 and the lining 21.

  The hole in the lining 21 is stepped for forming a countersink and a

  shoulder used to house and support the head 25 of the rivet 22 (Figure 1).

  This head 25 is opened out in contact with said shoulder. The other lining 21 has a hole 26 opposite the rivet 22 so that a lining can be fixed

21 then the other to disc 20.

  This is achieved in a riveting installation (FIG. 2) comprising a tool 30 and a counter-tool 40. The counter-tool 40 is axially movable relative to the tool 30, said stationary tool, while the counter-tool will be referred to as a mobile tool.

  and performs axial movements of descent and ascent.

  The movable tool 40 is adapted to bear on the shoulder of the rivet 22, while the fixed tool allows the head 25 of the rivet to be crushed in contact with

  3 0 the associated shoulder of the lining 21 when the movable tool 40 descends.

  The installation comprises (FIG. 2) a fixed frame 50 carrying a fluid jack, a vibrating bowl 70 filled with rivets, a supply 80 of the rivets 22 of the bowl 70 to the movable tool 40 having centrally a movable needle 41 intended to penetrate

  in the internal bore of the rivet 22 and to lower the rivet.

  The supply 80 generally consists of a guide channel with

  a split end allowing penetration of the barrels of the rivets into the slot.

  The needle 41 then makes it possible to grasp the rivets.

  The fixed tool 30 comprises a movable pilot 31, in the form of a rod with penetrating head. As will be understood an arm of a robot brings the lining of a and the disc at the level of the fixed tool 30 shouldered. Pilot 31 goes out to bring the holes

  of the trim and the corresponding disc.

  The needle 41 descends and concomitantly the pilot 31 retracts so that the rivet is brought into the corresponding holes. Then we go down

  the mobile tool 40 for riveting.

  Thus we see in Figure 3 in dotted lines the descent positions of the movable tool 40 having performed the race C. Here the tool is secured to the operating piston 2 of the cylinder 60. This cylinder

  has a nose 1 allowing its precise fixing relative to the fixed frame 50.

  The free end of the piston 2 is threaded. The mobile tool 40 has a guided shaft 42

  in translation by bearings 43 integral with the frame 50.

  The end of the shaft 42 is tapped for its attachment to the piston of

operation 2.

  The movable tool 40 is therefore secured to the operating piston 2 of the cylinder to

fluid 60.

  According to the invention, the stroke C of the mobile tool is not at constant stroke and a force sensor 90 is associated with the fixed tool 30. This force sensor is connected to a load monitor 91 capable of sending a signal to cylinder 60 for

  stop the lowering stroke of the operating piston 2 thereof.

  The monitor therefore makes it possible to control the working stroke of the jack 60 and to limit it. This monitor 91 is a measurement, command and control device. It includes a charge amplifier to transform the charge (force) generated by the sensor 90 into electrical voltage. An electric wire 92, here at

  several conductors, connects the sensor 90 to the monitor 91.

  Here the sensor 90 is advantageously a force sensor of the type

  precise, robust and space-saving quartz.

  The jack 60 has an amplifying piston 13, according to one characteristic, so that the jack is of the "pneumo-hydraulic" type. This cylinder comprises a control distributor, an output flow reducer and a return flow reducer associated with the control distributor, a limiter, a working stroke supply with a working stroke flow reducer, a pipe control threshold, a pneumatic servo connection, a pressure gauge, a pressure switch with pneumatic or electric contact

  and a pneumatic or electric oil shortage check.

  For more details, see Figure 5 showing the

  arrangements of the aforementioned components and the pipes.

  The control piston 2 is internally hollow to create a

  blind cavity 5 supplied with oil at the front of the jack.

  This piston 2 has a transverse collar delimiting two chambers suitable for being supplied pneumatically. Each room being suitable for being supplied from the control distributor via conduits. Arrows 16 and 17 respectively show the arrivals and departures of these rooms. These chambers are adapted to be filled with air and are therefore pneumatic chambers. The arrival and exit of the room associated with arrows 17 are connected by a conduit opening into a room

18 at the rear of the cylinder.

  This chamber 18 is delimited by the amplifying piston subjected to

the action of a return spring 12.

  More precisely, the fluid, here air, flows from the arrows 17 to the

  chamber 18 via a sequence valve 15 to distributor 14.

  An oil shortage warning light 8, an oil filling connection 9, an auxiliary oil tank 10, a closed circuit for the

  2 0 filling at spaced intervals.

  An unreferenced annular chamber, connected in 6 to the atmosphere,

  prevents air from entering the hydraulic circuit.

  A measurement and control connection 7 is also provided. There are further provided seals at 3 and 4 for the operating piston 2 and its

collar.

  As will be understood, it is possible, using the jack 60, to produce a

  approach race and this quickly at high speed and with reduced effort.

  To do this using the control distributor, the chamber associated with the arrows 17 is supplied, the chamber associated with the arrows 16 being

3 0 depressurized.

  When the tool 40 comes into contact with the shoulder of the rivet 22, the resistance created by the rivet 22 causes the valve to trigger.

  sequence 15, the compressed air then enters the chamber 18.

  The amplifying piston 13 enters with its plunger through the high pressure seal which separates the high pressure chamber 5 from the oil tank 10. A

work race then begins.

  The high oil pressure then acts on the piston 2 which is moved in a stroke C. As soon as the riveting force is reached, the sequence valve 14,15 is controlled, as well as the control distributor, by the monitor 91 and goes into escape. Indeed the monitor then sends an active signal taking into account

  of the information given by the force sensor 90.

  A return stroke is then carried out quickly under the action of the spring 12 bearing on the piston 13 and on a part 19 through which the

  plunger of piston 13, the chamber associated with arrows 17 being depressurized.

  The spring 12 also allows the part 19 to maintain pressure

  in the hydraulic tank 10. The part 19 is therefore a compensating piston.

  Thanks to the protection system 11 an excessive filling of oil is

1 0 excluded.

  The measurement and control connection 7 makes it possible to adjust the pressing force. Thus, for a determined force detected by the sensor 90, the working stroke of the jack 60 is stopped. The monitor 91 controls the working stroke of the jack 60

by ordering it to stop.

  Of course, the present invention is not limited to the embodiment described. In particular, the force sensor and the cylinder can have a

other configuration.

  The friction linings 21 can be split.

Claims (7)

  1- Installation of riveting friction linings (21) on their associated support disc (20), in particular for a clutch friction of a motor vehicle, comprising, carried by a fixed frame (50), on the one hand, a tool (30), said stationary tool, and, on the other hand, a counter-tool (40), said movable tool, movable relative to the stationary tool (30), said movable tool (40) being suitable for taking support on the shoulder of a rivet (22), the barrel of which crosses the support disc (20) and the friction lining (21), while the fixed tool (30) is intended to bear on the head ( 25) of the rivet (22) to open in contact with a shoulder of the friction lining (21) concerned, characterized in that the movable tool (40) is carried by a fluid cylinder (60), while the fixed tool (30) comprises a force sensor (90) and in that the force sensor is connected to a load monitor (90) making it possible to control the working stroke of the jack (60) in order to stop from a determined force by the force sensor (90).   2- Installation according to claim 1, characterized in that the sensor   force sensor (90) is a quartz force sensor.   3- Installation according to claim 1 or 2, characterized in that the   fluid cylinder (60) is pneumatic and hydraulic in nature.   4- Installation according to claim 3, characterized in that the cylinder (60) comprises an operating piston (2) with a flange separating two   clean rooms to be supplied with air.   - Installation according to claim 4, characterized in that the jack comprises an amplifying piston (13) for pressurizing a hydraulic chamber (5)   2 5 delimited in part by the internally hollow operating piston (2) for this purpose.   6- Installation according to claim 5, characterized in that the amplifying piston (13) delimits a chamber (18) in communication with a sequence valve (15) suitable for being activated by a signal from the monitor. load (91).   7- Installation according to any one of claims 1 to 6,   characterized in that the load monitor (91) is a device for measuring command and control.   8- Installation according to claims 6 and 7 taken together,   characterized in that the charge monitor (91) includes a charge amplifier for transforming the force generated by the quartz sensor (90) in tension.