FR2612464A1 - HYDRAULIC SERVO-CONTROL FOR PNEUMATICALLY ASSISTED CLUTCH - Google Patents

Abstract

HYDRO-PNEUMATIC SERVO-CLUTCH. THE PNEUMATIC MOTOR PISTON 25 AND THE HYDRAULIC MOTOR PISTON 17 ARE SEPARATED FROM THE VIEW OF THE CONSTRUCTION AND ARE IN EFFECTIVE LINKAGE IN TANDEM MODE, THE REALIZATION BEING SUCH THAT THE TWO ARE LIKELY TO BE ACTIVATED IN COMMON IN THE CASE OF 'A HYDRO-PNEUMATIC CONTROL, WHILE ONLY THE PNEUMATIC MOTOR PISTON 25 IS LIKELY TO BE ACTIVE IN THE CASE OF A PURELY PNEUMATIC CONTROL. APPLICATION TO MOTOR VEHICLES.

Description

Hydro-pneumatic servo-clutch.

  The invention relates to a hydro-pneumatic servo-clutch

  for motor vehicles, comprising, following

  a tandem arrangement in a crankcase, the pistons

  pneumatic and hydraulic motors which, under the

  a control valve connected to a hy-

  hydraulic, are able to act on a pressure rod

  common, actuating the clutch a catch device

  page of the game, with hydraulic mode of action, readjusting

  the stroke of the servo-clutch.

  The vast majority of commercial vehicles are equipped with mechanical transmission boxes. The reason

  is, among other things, the good performance of these transmissions.

  To improve the performance and performance of vehicles

  commercial vehicle transmissions are likely to be

  views of a large number of speed stages, which requires

  important physical and intellectual efforts of the

  in the shift. Using computers

  designed for vehicles, the passage of

  its can be automated and optimized.

  The clutch which is necessary for starting, for maneuvers and, generally, also for shifting, and which is provided between the engine and the transmission, is, in the great majority of

  vehicles, made in the form of a friction clutch, capable of

  wear; this clutch is controlled by the foot. The man

  in the case of large vehicles, general

  In the case of very powerful motors, a pneumatic servo-clutch is used. In the context of a known servo-servicing (patent application published in the Federal Republic of Germany under

  No. 2,124,948) a motor or hydraulic working piston

  that and a servo-piston or piston engine or pneumatic work operate inside a single housing. The two pistons are coupled together, that is to say linked together for common movements, being noted that

  the inside of the piston rod device, which is

  With both pistons is provided a cylinder chamber which is filled with a hydraulic medium. The pusher

  which loads the clutch, and which extends from the

  with pistor rods, supported by a piston

  against the hydraulic environment contained in the chamber.

  cylinder. In addition, means are provided which, for a predetermined operating position, connect the hydraulic pressure chamber of the control device.

  from the clutch to the cylinder chamber, and that of such

  sound that readjustments or retrofit play the play of the support piston, compared to the device rods

pistorns, be made possible.

  From the foregoing, the object of the invention is to improve a control device in the form of a hydraulic servo-clutch of the kind

  recalled above, so as to make it possible to

  partially automated clutch, and this by the

  implementation of modern electronic means which

  in partial parts, the manual control of the clutch or clutch. The control device must be able to be lined with components or elements of a common type, that is to say that one must be able to operate, with the possibility of a manual control with a master cylinder

  Conventional and of a current order per push,

  calf of the clutch. In particular, it must be possible to be assured of an emergency control of the clutch

  in the event that the electronic device were to

need.

  To solve this problem, the servo-clutch se-

  invention and which is of the kind recalled at the head of

  memory, is characterized by the fact that the piston mo-

  pneumatic motor and the hydraulic motor piston are

  trimmed between them from the point of view of the construction and are effectively connected in tandem mode, the realization being

  such that both are likely to be activated in

  in the case of a hydro-pneumatic control, whereas only the pneumatic piston motor is likely to be

  activated in the case of purely pneumatic control.

  Variations of the subject of the invention are

  achieved by the fact that: - the hydraulic device of the catch of the game is disposed in the pneumatic piston engine and can move with it; that on the side of the pneumatic driving piston, away from the pressurized medium, are arranged two chambers which

  are filled with a hydraulic medium which are separated

  likely to be connected to each other by a

  positive valve, the first of the rooms being

  inside the piston rod and is limited by a piston

  a push-button which is displaceable in the piston rod and which is connected to the pressure rod of the servo-clutch, the embodiment being such that when the valve device is open, relative displacements of the push-piston

  trigger volume shifts between the two chambers

bers;

  - that the second chamber is limited by a piston-

  compensator which is loaded by a spring and which is de-

  place for the balancing of volumes, and that the

  valve is located at the end of the piston rod.

  tone, which is close to the inner side of the pneumatic piston engine;

  - that the piston rod is displaceable limitatively-

  relative to the pneumatic motor piston, and that of

  such that in the case of a pneumatic pressure

  of the engine piston and a relative approach

  be the engine piston and the piston rod, the device

  valve is likely to be closed by the piston

  tor; - that the hydraulic motor piston is supported, with a pusher that extends axially from

  he, in a cavity of the pneumatic piston engine,

  such that the hydraulic motor piston

  tends, with sealing, through an intermediate wall located between the casings of the two engine pistons; the control valve can be controlled both hydraulically by the cylinder and pneumatically by a solenoid valve; and

  - that the control piston of the control valve

  of, and which is likely to be controlled hydraulically,

  consists of two individual pistons, the hy-

  hydraulic acting on all of the two pistons, while the pneumatic control acts, by the solenoid valve, on one of the pistons, the embodiment being such that in the case of a hydraulic control, both the piston engine

  hydraulic that the pneumatic piston engine are susceptible

  to be activated, whereas in the case of an order

  only the pneumatic piston is capable of

  tible to be activated, while the hydraulic

that is at rest.

  Due to the planned construction separation in

  a device, between the engine piston or hydraulic

  that and the piston engine or pneumatic work, it is possible to operate the control device in part

  purely pneumatic or hydro-pneumatic

  than. In the case of a purely pneumatic control, the control valve which is also, by construction, integrated in the apparatus, is capable of being loaded independently of the hydraulic valve system, so that the hydraulic working piston being in the rest position, the pneumatic piston engine can also

  to be in charge. For this purpose, the control valve is sus-

  able to be controlled by a solenoid valve that can

  be influenced in the context of modern electronics.

  As a result, the automated control of the clutch is made

  possible for certain operating states.

  Another notable advantage of the control device

  results from the fact of the presence in the piston engine tire-

  in the direction of traction and pressure, it is noted that the compensating volume chamber which is used for this purpose is completely filled, without any connection with it. the hydraulic working medium in the pressure chamber of the hydraulic motor piston. A

  any problem of bubble formation,

  ration of the hydraulic medium in the volume chamber of

  compensation or readjustment are, therefore, entirely

  excluded. In addition, it is also possible to predict

  different hydraulic environments both for the com-

  hydraulic motor piston only for the process of

catch up game continuously.

  The separation between the hydraulic piston and the piston

  in this way, your tire is advantageous for the control process under the control of the solenoid valve, that the hydraulic piston does not need to be driven, which means that no unnecessary replenishment of the hydraulic working chamber or the pressure chamber of the hydraulic motor piston is required. In what follows, the invention will be explained using an exemplary embodiment, with reference to the longitudinal sectional view of the servo-clutch. In the drawing, there is shown a servo-clutch in which is integrated, as described below,

  a control valve 1. The control valve 1 is

  linked, using a pipe 3 for a hydraulic medium,

  to a master cylinder 5 with hydraulic mode of action. May-

  5-cylinder is, in a manner known in itself, capable of being controlled by means of a clutch pedal 7. At the

  In addition, the control valve 1 is connected via

  diaire of a pipe 9, a solenoid valve 11; electro-

  The valve may be ordered with the aid of a

  positive control (not shown), in order to pass compressed air through the pipe 9 into the valve

order 1.

  The servo-clutch is composed, as a unit

  two casings 13 and 15. Inside the casing 13 is mounted a hydraulic motor piston 17 which

  is likely to be charged, by the introduction of a

  hydraulic locus in a cylinder chamber 19, and this

  in such a way that when it is loaded under pressure

  place to the right on the drawing. The engine piston 17 crosses, according to the figure, and with a pusher which is shaped there, the separation zone between the two casings 13 and 15, while it bears against a bowl 23 which is shaped in a surface close to a pneumatic engine piston 23. The engine piston 25 is capable of

  to be charged, as described below, by the introduction of

  compressed air duct in the chamber 27, and that in such a way that it is able to move to the right in the drawing. The engine piston 25 which is guided with respect to

  the inner wall of the housing 15, at its outer periphery

  re, preferably with the aid of a guide ring 25 of a sealing means 39, has an axial appendage 33 having

  the shape of a socket, appendix in which is susceptible

  Sealing slide with sealing, a compensation piston 35 arranged in coaxial position. The compensation piston

  is guided, on the outside, and sealed with

  port at Appendix 33, and door, on the inside and sealingly, against the outer periphery of a piston rod 37. The compensation or balancing piston is permanently loaded by a spring 39 in the direction

  of the pneumatic working piston 25, being noted that the

  fate 34 is supported, in the manner shown, against a stop stirrup 41 which is fixed internally on the appendix 33. A second spring 43, which is supported

  against the abutment stirrup 41 acts on the outer periphery.

  piston rod 37 and continuously

  ci in the direction of the pneumatic piston engine 25. A third spring 45 bears against the abutment stirrup 41, on the opposite side with respect to the springs 39 and 43, and extends to a support element 47 arranged in the

  bottom 49 of the housing or housing 15. The spring 45 acts directly

  against the engine piston 25 and has a tendency to

  move to its starting position as it is

presented in the drawing.

  On the outer periphery of the piston rod 39 are provided, with an axial distance between them, two

  stops, a stop disc 51 and a stop ring 53.

  The radially inner end of the insertion element 47 is in the form of a stationary stop 55, being noted that between the stop 55 and the bottom 49 of the housing, is maintained a stop disk 57. stop disk 57 serves as an end stop for the base of the stop ring 53 as it moves, with the piston rod 37

  to the right, while the stop disk 51 comes

  against the stop 55, when the piston rod 37 executes

  a displacement directed to the right.

  The compensation piston 35, mentioned above, delimits with the pneumatic driving piston 25 an inner chamber which serves to receive a hydraulic medium under pressure. The pressurized hydraulic medium is introduced

  in room 59 before assembly of the am-

  plificatrice, and after opening a cap 61 which

  located in the engine piston 25. The chamber 59 extends

  FIG. 1 is a view of a gap valve 68, which, in the closed state (as shown), isolates the chamber 59 from a second chamber 65 for receiving the pressurized hydraulic medium. The catch-up valve 63 is constituted by a ball valve 69 which is loaded by a spring 67, and which is capable of ensuring

  sealing with respect to a valve seat 71.

  When the pneumatic piston 25 is pressed against the valve ball 69, the valve ball 69 is held in its sealing position on the valve seat, that is to say that the valve ball 69 opens, under force. of the spring 67, when there is a relative axial movement in the direction of a mutual separation of the piston rod 37 and the engine piston 25. Inside the chamber 59 is provided a

  guide ring 73 which extends axially from the piston

  your motor 25 and which is open, which guide ring

  acts as a guide for the piston rod 37, and that of such

  the way that forces that act on the piston rod

  37, in transverse direction, are absorbed by the piston

  your motor 25 and by the guide ring 29 with respect to

casing 15.

  The driving piston 17 acts during the introduction of a hydraulic medium under pressure into the cylinder chamber 19, against the pneumatic piston 25, and moves,

  with the latter, to the right, in the way that will be de-

  further, noting that the introduction of compressed air

  m in the chamber 27 triggers an amplification action.

  261246z4 As a result of the separation between the engine piston 25 and

  the engine piston 17, it is possible to carry out a pneumatic load

  of the working piston 25, without necessarily leading to the fact that the hydraulic piston 17 must be loaded at the same time. In the case of a purely pneumatic

  the chamber 27, and controlled by the introduction of compressed air

  awarded with the control valve 1, the piston

  pneumatic driver 25 moves in the direction of disengagement, being noted that the engine piston 17, when the chamber of

  cylinder 19 is devoid of pressure, remains in its posi-

  represented departure. We do not need

  refuel in hydraulic medium in the cylinder chamber 19. The starting position, as shown,

  of the engine piston 17 which is guided with sealing against

  port to the inner wall of the cylinder chamber 19,

  is provided by a stop disk 75 which is guided at

  calf of the pusher 21. This thrust disk is, in turn,

secured by a circlip 77.

  The operating mode of the servo-clutch is as follows: If the control valve 1 is activated in the usual way, by operating the master cylinder 5 with the help of

  the clutch pedal 7, the hydraulic pressure medium

  that arrives, while passing by the pipe 3, in the room

  79 of the control valve and the latter, via

  channel 81, in the cylinder chamber 19, and

  this in such a way that the driving piston 17 is loaded hy

  hydraulically, that is, moved to the right. At the same time, the pressure prevailing in the chamber 79 acts on the two-part control piston 81, 83, which control piston 81, 83 is displaced, against the force of the spring 85, to the right in the drawing until it raises a valve plate 87 and thereby a chamber 89 which is connected to a reserve tank

  pneumatic, is connected to chamber 91 and through

  of this and a link (not shown) to the chamber 27. With this connection then begins to make feel the servo-effect of the servo-clutch, the engine piston 25 and the piston 17 which is susceptible to be loaded hydraulically, provide the command force. The force is

  transmitted from the pneumatic motor piston 25, via

  of the valve ball 69 and the valve seat 71,

  with sealing by the hydraulic volume which is

  in the chamber 65, on the plunger 93, the control stroke being determined by the predetermined volume of the master cylinder, at the clutch pedal 7. The

  tilting movements that may appear, are

  due to possible by the engine piston 25, through the guide ring 29. The piston-push 93 acts, to

  using the push rod 95 on the disengagement, that is to say

  say that the clutch is disengaged when the piston of

  The valve is controlled in the direction of the arrow A. When actuating the solenoid valve 11 which is controlled by a control unit, the chamber 97 which is connected to the pipe 9, is pneumatically charged, whereby the individual pistons 83 raise, against

  of the spring 85 the valve plate 87 of its seat

  mission, which has the consequence, as already mentioned, of connecting the chamber 91 with the chamber 27. The working piston 25 is pneumatically loaded, without at the same time the engine piston 17 is loaded hydraulically; the

  piston 17 remains stationary, as has already been ex-

  higher, so that the cylinder chamber 19 does not have to undergo a filling station with the medium

under hydraulic pressure.

  At the exit of the pneumatic piston engine 25, which is controlled by an action exerted on the clutch pedal 7 or by activation of the solenoid valve 11, the

  stop disc 51 acts relative to the stop 55, that is

26q246 1 1

  to say that the race is limited; the position of the

  your push-button 93 relative to the piston rod 37 is

  provided, according to the drawing, by circlip 101.

  turn of the engine piston 25, the stop 53 acts relative to the stop disc 57, being noted that at the same time the stop position of the valve ball 69 is determined at the

of the engine piston 25.

  The return of the servo-clutch o the closure of

  the clutch takes place by reducing the pressure in the chamber

  79 (with disengagement of the clutch pedal 7) or by reduction of pressure in the chamber 91 (with control by the solenoid valve 11), with the result that the chamber 27 is connected to the atmosphere via a link (not shown) and that the control valve 1

  is deaerated. In the case of prior manual control,

  re, that is to say a load hydraulic pressure resulting for the cylinder chamber 19, the latter is also relieved of any pressure. The return of the hydraulic engine piston 25 or (during manual control) the simultaneous return of the engine piston 25 and the engine piston 17

  takes place under the effect of recall forces at the level of

  by means of the plunger 93 (passage of forces) as well as by the spring 45. With the aid of the spring and, furthermore, after application of the abutment ring 101 against the abutment disc 57 and the stop 55, the valve seat located between the valve ball 69 and the valve seat 71 is opened by means of the spring 67, which establishes

  the connection between Chamber 65 and Chamber 59. This

  sus allows displacements of the push-piston 93 in the

  direction A and in direction B. In the case of

  in direction B, the clutch lining is readjusted according to wear. The volume discharged from the chamber 65, during a displacement of the plunger piston 93 in the direction A or B, is received in the chamber 59 which acts as a volume compensator, being noted that thanks to the compensation piston 35 and under the action of the spring 39, the volume in the chamber 59 can be changed. Depending on the design of the spring 39, it can prevail, in the chambers 59 and 60, and when the apparatus is de-aerated, a determined pressure which always maintains the piston piston 93 in

  application against the clutch release lever. Characteristics

  The spring 43 depends on this pressure, said spring providing, as a function of the resulting annular surface, between the diameter of the plunger 93 and the

  inner diameter of the compensation piston 35, the closure

  ball seat when ordering the unit.

  As mentioned above, the chambers 59 and 65 are filled in a hydraulic medium via the bore which is sealed with the plug 61. The air in the chamber 33 is connected, by a deaeration valve (not shown)

  with the atmosphere, that is to say that variations in the volume of

  me in room 103 are possible, without any difficulty

  and without the appearance of an overpressure or

pressure.

2 6 1 2 4 6 4

Claims (8)

  1. Hydro-pneumatic servo-clutch for vehicles   vehicles, comprising, in a tandem arrangement in a housing, the pneumatic and hydraulic piston motors which, under the control of a control valve connected to a hydraulic master cylinder, are capable of   to act on a common pressure rod, actuating the em-   clutch, a device for catching up the game, with a mode of action   automatically readjusting the stroke of the servo   disengagement, characterized in that the pneumatic motor piston (25) and the hydraulic motor piston (17) are structurally separated from one another in construction and are effectively connected in tandem mode, the embodiment being such that both are may be activated jointly in the case of a hydro-pneumatic control,   whereas only the pneumatic piston (25) is   tible to be activated in the case of purely pneumatic control.   2. Servo-clutch according to claim 1, characterized   the fact that the hydraulic device of the rat-   game page is arranged in the pneumatic piston engine   (25) and can move with it.   3. Servo-clutch according to claim 2, characterized   characterized in that on the side of the pneumatic motor piston (25), remote from the pressurized medium, two   chambers (59, 60) which are filled with a hydraulic medium   which are separable or capable of being interconnected by a valve device (67, 69, 71), the first (65) of the chambers being within the piston rod (37) and limited by a pusher piston (43) which is movable in the piston rod (37) and which is connected to the pressure rod (95) of the servo-clutch,   the embodiment being such that when the device with   pope is open, relative displacements of the piston-pushes   evening (93) trigger volume shifts between two bedrooms (59, 65).   4. Servo-clutch according to claim 3, characterized   characterized by the fact that the second chamber (59) is limited   by a piston-compensator (35) which is loaded by a res-   and is movable for volume balancing, and the valve device is located at the end of the piston rod (37), which is close to the inner side of the pneumatic engine piston (25).   5. Servo-clutch according to claim 4, characterized   characterized by the fact that the piston rod (37) is moved   limitively with respect to the pneumatic motor piston (25), so that in the case of a load   pneumatic pressure of the engine piston (25) and a   between the engine piston and the piston rod, the valve device may be closed by the engine piston.   6. Servo-clutch according to claim 1, characterized   characterized by the fact that the hydraulic motor piston (17)   is supported by an axially extending pusher (21)   from it, in a cavity (23) of the piston   pneumatic cylinder (25), the embodiment being such that the hydraulic motor piston (17) extends, with sealing, through an intermediate wall located between the housings (13, 15) of the two engine pistons. 2 6 1 2 L 6 4   7. Servo-clutch according to claim 1, characterized   by the fact that the control valve (1) is sus-   it can be controlled hydraulically by   the master cylinder (5) only pneumatically by an elec- trovanne (11).   8. Servo-clutch according to claim 7, characterized   controlled by the fact that the control piston (81, 83) of the   control valve (1), and which is likely to be   hydraulically, consists of two pistons indicated   viduals (81; 83), the hydraulic control acting on   both pistons, while the pneumatic control   the solenoid valve (11) acts on one (83) of the pistons.   the realization being such that in the case of a   both the hydraulic motor piston and the pneumatic motor piston are capable of being activated, whereas in the case of pneumatic control only the pneumatic motor piston can be activated, whereas the hydraulic motor piston ( 17) is at rest.