JP2003534198A - Servomotor with deformable sleeve and equipment for adjusting this sleeve - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention includes a drive piston for a master cylinder and an elastically returned control rod that slides within the piston as a function of input, the end of the rod being a plunger. And a finger (52) is slidably fitted on the plunger to bias the reaction disk of the drive rod to transmit the reaction force of the piston to the control rod, and the one-way clutch device comprises a key (60); A sleeve (58) fitted with a finger (52), said sleeve being slidably fitted on the plunger and independent of the control rod when the control rod is driven at a predetermined speed. In a brake servomotor that can be locked to a movable piston, first and second adjustments are provided in which a sleeve (58) can be plastically deformed axially to adjust the servomotor before assembly. To provide a brake servomotor, characterized in that it comprises a capacity portion (104, 106). The present invention also provides equipment for plastic deformation of said sleeve (58).

Description

Detailed Description of the Invention

The present invention relates to pneumatic servomotors used to assist in braking a motor vehicle.

More particularly, the present invention comprises a rigid casing in which a transverse bulkhead is movable and which varies between a front chamber under a first engine negative pressure and between engine negative pressure and atmospheric pressure. And a rear chamber under a second pressure in an airtight manner; a movable piston that moves integrally with the movable partition wall together with the partition wall, and a return spring that resists the return force exerted on the control rod. With a control rod that selectively moves in the piston as a function of the axial input exerted in a direction; the end resulting from the control rod applying an input at an intermediate drive position or at a predetermined high speed. A three-way valve including at least a plunger disposed in a front portion of a control rod in a piston and an annular valve seat supported in a rear portion of the plunger. The three-way valve by connecting the front chamber to the rear chamber, especially when the control rod is in the rest position, or by gradually connecting the rear chamber to atmospheric pressure when the control rod is actuated. , A type capable of varying the second pressure in the rear chamber; in the end drive position of the control rod, the rear surface of the finger slidably fitted to the front end of the plunger is biased by the plunger. , A front face of the finger contacts a recoil disk integral with the movable piston and transmits the reaction force of the movable piston to the plunger and the control rod; and at least one finger sliding on the plunger and having a finger at its front end. Moveable between two coaxial tubular sleeves and a non-actuated position in which the sleeves do not cooperate and an actuated position controlled by the drive position of the control rod A one-way clutch device including a latching element, in which the latching element cooperates with the locking element of the sleeve in this actuated position to enable the finger to lock the movable piston independently of the plunger and control rod. The present invention relates to a pneumatic servomotor for auxiliary braking of a vehicle, which is of a type that locks a sleeve in a front end axial position.

In a known manner, such a design is most suitable for safety in case of emergency braking situations.

In fact, conventional servomotors do not include a finger or a one-way clutch device for the finger. Thus, the finger can directly bias the reaction disc integral with the rear surface of the movable piston.

In all braking situations where maximum braking force is exerted on the control rod, actuation of the control rod actuates the finger-forming plunger, which results in maximum opening of the three-way valve,
Therefore, the rear chamber receives atmospheric pressure. Thus, the movable bulkhead moves forward and the end of the plunger contacts the reaction disc integral with the rear surface of the movable piston.

Therefore, the force exerted on the movable piston when the control rod reaches the end of its travel is the assisting force that results from the force exerted on the movable piston by the finger-forming plunger and the pressure difference on both sides of the movable partition. Results from In addition, the driver will feel the braking reaction force transmitted from the movable piston to the plunger via the reaction disc.

In fact, when encountering an emergency braking situation, many drivers underestimate the actual risk incurred and, after braking hard, maintain considerable force in order to avoid an accident. It has been established that you will release some braking power when you should.

In the case of a full braking situation with a rapid movement of the control rod, the plunger touches the reaction disc before the maximum pressure difference between the front and rear chambers is actually reached and the maximum braking effect on the driver is reached. It may be sensational and this may result in the driver releasing the braking force, even if it should be maintained to benefit from the maximum braking force.

Servomotors, such as those of the type described above, lock fingers in contact with the reaction disc by securing the sleeve, resulting in maximum force even if the driver releases some of the braking force. It makes it possible to eliminate problems such as being retained on the rear surface of the movable piston.

Moreover, the one-way clutch device for a servomotor is considerably cheaper to manufacture because the fingers are coupled to the sleeve.

However, servomotors of the type described above suffer from the need for compliance with precise manufacturing dimensions for the sleeve.

In fact, in such a servomotor, the sleeve to which the finger is attached is
In the rest position it is provided that there can be a certain gap between the finger and the reaction disc.

The size of the gap determines the auxiliary force actually supplied by the movable piston, with respect to which the reaction force is transmitted from the movable piston via the reaction disc to the control rod. The magnitude of the assisting force is commonly referred to as the "jump" of the servomotor, which depends on the dimensions of the fingers and especially the thickness of the fingers.

Moreover, in this servomotor, when an input is applied to the control rod at a speed higher than a predetermined speed, the axial position of the locking element of the sleeve is the time when the one-way clutch device is about to start. The condition is the speed at.

The speed is commonly known as “light speed”, and thus this speed is
It depends on the predetermined dimensions of the sleeve, and more particularly on the axial distance between the front end of the plunger and the locking element of the sleeve.

Conventionally, the locking element of the sleeve is a shoulder-forming lateral surface, so that when the sleeve is manufactured using a machining process, more particularly a shaping lathe,
It is suitable for the acoustic performance of the servo motor. In this case, the dimensional requirements are met by the process itself.

This design has the drawback of adding significantly to the cost of the sleeve, as it must follow exact dimensions.

To address this difficulty, the present invention provides a sleeve whose dimensions can be adjusted simply by a plastic deformation process.

Accordingly, the invention includes a sleeve having a first adjusting portion located between the front and rear surfaces of the finger and a second adjusting portion located between the rear surface of the finger and the locking element. A servomotor of the above type characterized in that both parts are plastically deformable in at least the axial direction so that the servomotor can be adjusted before assembly.

According to another feature of the invention, the latch element comprises a substantially annular key surrounding a sleeve with a predetermined gap, the key being provided when an input is applied at a predetermined speed. Driven by a movable piston, the key peg can be swung about a substantially lateral axis so as to abut the rear lateral surface of the sleeve which constitutes the locking element; the sleeve has fingers at its ends. A tubular anterior cylindrical portion comprising a tubular posterior cylindrical portion having a diameter substantially greater than the diameter of the anterior portion and including a radial groove, the shoulder forming anterior lateral surface of the groove being locked posterior lateral The front portion includes an inner annular flange projecting from the rear surface of the finger and extending rearward, said flange adjusting the position or jump of the servomotor with which the finger biases the reaction disk. Is axially deformable prior to assembly to form a first adjusting portion for: a front portion and a rear portion of the sleeve are separated by an intermediate portion having a reduced thickness, the intermediate portion being a locking rear Is axially deformable to form a second adjustment portion for adjusting the nimble position of the key peg against the lateral surface; the groove is generally behind the shoulder forming front lateral surface. Presents a frustoconical contour; the peg has the shape of a concave frustoconical angular sector which complements the frustoconical contour of the groove in the sleeve; the key has the shape of a tee in axial cross section The vertical branch is oriented substantially radially and is traversed by the sleeve, while the substantially axially oriented horizontal branch is pierced at a right angle to the axis of the piston. Housed with no axial gap between two opposing walls of the cavity across the ton,
Allows swinging movement of the key in the cavity; the front horizontal half-branch of the tee-shaped key has a surface that faces the sleeve radially and the pegs project; Two compression springs arranged between the blind holes for centering the tee-shaped key on both sides of the sleeve and the front lateral wall of the cavity elastically act against the rear lateral wall of the cavity. Being biased; the sleeve is made of a material that exhibits low elastic limits and high toughness.

The invention is also a facility for plastic deformation of a tubular sleeve used in a pneumatic servomotor of the type described above, comprising a first adjusting part in the front-back direction towards the inner part of the sleeve. A deformable coaxial annular flange having a tubular outer cylindrical portion of a predetermined outer diameter closed at its ends by a front lateral wall extending therefrom and a second adjusting portion having the same outer diameter as the front portion. An apparatus is provided that includes a deformable intermediate portion and a tubular posterior cylindrical portion having a predetermined diameter greater than that of the anterior portion and including at least one shoulder forming posterior lateral surface.

Thus, the present invention provides a facility of the above type, wherein the facility comprises tubular, coaxial male and female dies, with a sleeve disposed between the dies to provide a single axial direction. Provided is a device characterized in that it is deformed in a compression deformation process, where it is axially pressed together to obtain the predetermined required dimensions for the mold, the first and second adjusting parts at the same time. ing.

According to another feature of this arrangement, the inner diameter of the tubular female die is larger than the outer diameter of the rear portion of the sleeve, the female die including a rear lateral wall with a cylindrical bearing surface extending in a forward direction. , The wall is fitted with a sleeve such that the front end of the cylindrical support surface rests on the annular flange of the sleeve; the male mold has a hole whose diameter corresponds to the outer diameter of the front part of the sleeve. A first side of a predetermined length, with a male die projecting rearward and continuously disposed in a tubular female die, including a front transverse bottom portion supporting a front transverse wall of a front portion of the sleeve. A convex cylindrical bearing surface designed to receive the tubular adjustment shim of the device; and a facility for attaching a pressured forward tubular spacer to the sleeve for axially contacting the shoulder forming lateral surface of the sleeve. A second posterior tubular adjustment shim having a predetermined length, However, both the spacer and the shim provide a fitting inside the female mold between the female cylindrical support surface and its inner cylindrical wall prior to the axial compression deformation process; The female mold is fixed, and is mounted slidably in the axial direction so that the female mold is pressed toward the male mold with a predetermined value of compressive force.

Other features and advantages of the present invention will be apparent from the following detailed description with reference to the accompanying drawings.

In the following description, the same elements or elements having similar functions are denoted by the same reference numerals.

In principle, the terms “anterior”, “rearward”, “upper” and “lower” refer to elements or positions facing left, right, upper or lower in FIGS. 1 to 4, respectively.

[0027]   FIG. 1 shows a pneumatic servomotor 10 for auxiliary braking of a motor vehicle.

In a known manner, the pneumatic servomotor 10 contains a rigid casing 12 in which a transverse bulkhead 14 is movably mounted and has a value equal to the negative pressure value of the vehicle engine. Of the anterior chamber 16 under the first pressure "P ₁ " of the second pressure "P ₂ "
A lower rear chamber 18 is defined therein. The second pressure “P ₂ ” may change between the engine negative pressure value “P ₁ ” and the atmospheric pressure “P _a ”, as described later.

The front chamber 16 is supplied with a pressure “P ₁ ”, for example a negative pressure in the intake manifold (not shown) of the vehicle engine, via a negative pressure pipe 20 connected to the vacuum source of the vehicle.

The pneumatic servomotor 10 includes a movable piston 22 integral with the movable partition wall 14. In the casing 12, the movable partition wall 14 is elastically returned by a return spring 24, which springs the front face 2 of the casing 12 and the movable piston 22.
Go to 6. The front surface 26 of the movable piston 22 carries a reaction cup 30 in which a reaction disc 32 made of an elastomeric material is housed in the manner described below. The front surface 34 of the reaction cup 30 is integral with the drive rod 28,
Therefore, this rod moves with the movable piston 22 to drive the hydraulic brake master cylinder 36 of the vehicle.

The control rod 38, which is connected to the brake pedal of the vehicle, for example via a connecting sleeve 41 arranged at its free rear end 43, is movable as a function of the axial input applied to the control rod 38 in the forward direction. It can move selectively within the piston 22. The driving force is exerted against the return force applied to the rod 38 by the return spring 40 arranged between the movable piston 22 and the control rod 38.

FIG. 2 shows a toggle rod 42 in which the front end of the control rod 38 is housed in a complementary housing 44 provided on a substantially cylindrical plunger 46 slidably mounted in the movable piston 22. It shows more clearly that it is shaped.

The rear annular valve seat 48 of the plunger 46 is specifically connected by connecting the front chamber 16 to the rear chamber 18 when the control rod 38 is in the rest position, or by the control rod 3.
When the valve 8 is driven, it belongs to a three-way valve 50 capable of changing the second pressure "P ₂ " in the rear chamber 18 by gradually flowing the atmospheric pressure "P _a " into the rear chamber 18.

The mode of operation of the three-way valve 50 is known in the art and will not be described further here.

In a known manner, the fingers 52 are formed on the front end of the sleeve 58 and are slidably fitted on the front end of the plunger 46 opposite the housing 44. In addition, the front end of the sleeve 58 that constitutes the finger 52 has a reaction cup 30.
Is slidably fitted in a hole 54 provided in the movable piston 22 so as to open opposite to. Therefore, the sleeve 58 and the finger 52 can be biased by the plunger 46 so that the finger 52 sequentially biases the recoil disc 32 to compress it.
Therefore, the reaction force of the movable piston 22 is transmitted to the plunger 46, and consequently to the control rod 38 at the stroke end drive position of the control rod 38.

As is well known, as shown in FIGS. 2 and 3, the servomotor 10 comprises, on the one hand, a locking element forming part of a coaxial sleeve 58 and, on the other hand, around the sleeve 58 with a radial clearance. A one-way clutch device 56 including a movable latching element consisting of a generally annular key 60 fitted in.

Therefore, the coaxial sleeve is slidably fitted on the plunger 46, and the plunger 4 is inserted through the spring 57 arranged between the piston 22 and the sleeve 58.
6 is elastically returned to contact the front lateral surface 59 of the 6.

Moreover, when the servo motor 10 is in the assembled state, the sleeve 58 penetrates the circular opening 61 provided in the key 60.

The key 60 is housed in a cavity 62 that intersects the piston 22 at right angles to its axis “A”. The key 60 is elastically biased to abut the rear wall 66 of the cavity 62.

In a known manner, in the rest position shown in FIG. 2, the lower part 70 of the key 60 is supported on a support 72 provided on the casing 12 of the servomotor 10. The lateral pin 71, which laterally penetrates the sleeve 58 and the plunger 46, is provided on the control rod 3
In the rest position of 8, the front surface of the key 60 abuts so as to define the rest position of the plunger 46.

When the input is applied to the control rod 38 at a reduced speed, the front chamber 16 and the rear chamber 18 are
The equilibrium of the pressure at the movable partition 14 and the movable piston 22 causes the plunger 4
6 is slow enough to move at a speed approximately equal to the speed of the sleeve 58 driven by 6. As described further below with respect to the servomotor 10 according to the present invention,
At this point, the one-way clutch device 56 remains inactive because the key 60 rests on the sleeve 58.

On the other hand, as shown in FIG. 3, according to the full travel of the control rod 38, when an input is applied in the forward direction at a predetermined speed of this rod, the plunger 46 is higher than the speed of the movable piston 22. Drive the sleeve 58 at a speed. As a result, the upper portion 64 of the key 60 is driven by the piston 22, while its lower portion 70 separates from the support 72. Since the key 60 no longer rests on the sleeve 58,
The key swings counterclockwise about a generally lateral axis to cooperate with a locking element on the outer periphery of the sleeve 58, and more specifically on the rearward lateral surface 76 of the sleeve.

Therefore, if the driver releases the force exerted on the control rod 38 too early,
The sleeve 58 is locked in the axial front end position by the key 60, in which the finger 52 biases the reaction disc 32 independently of the plunger 46 and the control rod 38, which means that the return of the control rod 38 is three-way. This means that the maximum braking force is maintained unless the valve 50 is opened again and the piston 22 is moved backward in the return direction.

In a known manner, the one-way clutch device 56 includes a latching element or key 6 described above.
Although shown in the figures as including 0, it is understood that the device may include other types of movable latching elements capable of accurately axially locking the posterior lateral surface 76 of the sleeve 58. It is logical.

The servomotor 10 of the present invention, described in detail with reference to FIGS. 2 and 3, includes a one-way clutch device 56 having a peg 78 on a tee key 60, the peg of the clutch device. In the operative position, it abuts against the locking element forming rear lateral surface 76 of the sleeve 58 to lock the sleeve 58 in the correct axial position.

FIG. 4 shows that the sleeve 58 has a tubular front cylindrical portion 79 which at the end constitutes the finger 52 and a tubular rear cylindrical portion having a diameter substantially larger than the diameter of the front portion and including a radial groove 80. 83 to indicate that the shoulder forming anterior lateral surface of the groove is the locking posterior lateral surface 76. Thus, the radial groove 80 defines in the rear portion 83 a front cylindrical abutment surface 81 and a rear cylindrical abutment surface 85.

The groove 80 has a generally frustoconical profile behind the shoulder forming front lateral surface 76. As a result, the end of the groove 80 opposite the shoulder forming front lateral surface 76 gradually merges into the cylindrical outer periphery of the rear portion 83 of the sleeve 58.

The frusto-conical shape of the groove 80 formed in the sleeve 58 is particularly advantageous in that its peg 78 can be guided during rocking of the key 60, said peg forming the shoulder formation of the sleeve 58. Up to its rest position with respect to the anterior lateral surface 76, it has the shape of a concave frustoconical angular sector which complements the frustoconical contour of the groove 80.

The circular opening 61 formed in the key 60 and surrounding the sleeve 58 is
Does not contribute to the lock. It is the peg 78 that is in charge of this locking function.

In fact, as shown in detail in FIGS. 2 and 3, the key 60 has the general shape of a tee in axial cross-section, its vertical branch 82 being substantially radially oriented, It includes an opening 61 that is traversed by the sleeve 58. The tee key 60 includes a horizontal branch 84, which is the main branch 82.
No axial gap between the rear wall 66 and the front wall 68 of the cavity 62 that is substantially axially oriented at right angles to and intersects the piston 22 at right angles to the axis "A" of the piston 22. It is housed in.

Such a configuration presents the advantage of allowing only oscillating movement of the key 60 within the cavity 62. In fact, the key 60 cannot move axially with respect to the cavity 62, but its branch 84 can swing within the cavity 62, as shown in FIG.

The peg 78 is located below the horizontal branch 84-60 of the tee key 60. More specifically, the horizontal half-branch 86 in front of the tee key is
8 has a surface that faces in the radial direction and from which the peg 78 projects.

The tee key 60 is arranged between the blind centering hole 96 of the tee key 60 provided on each side of the sleeve in the vertical branch 82 of the tee and the front lateral wall 68 of the cavity 62. Two compression springs 94 and 95 elastically bias the rear lateral wall 66 of the cavity.

As a result, when no force is exerted on the control rod 38, the key 60 is positioned as shown in FIG. 2 and its horizontal branch 84 is substantially parallel to the axis A of the piston 22. In contrast, its vertical branch 82 is substantially perpendicular to the axis A.

When the driver drives the control rod 38 at a relatively low speed corresponding to the incremental braking, the atmospheric pressure “P _a ” is gradually established as the three-way valve 50 is opened, so that the operation is movable. The piston 22 moves substantially at the same speed as the plunger 46. In this configuration, the horizontal branch 84 is retained between the rear wall 66 and the front wall 68 of the cavity without the possibility of axial movement, so that the vertical branch 82 of the key is a support 72 integral with the casing 12. Once separated from, the key 60 will rock. The peg 78 then comes into contact with the sleeve 58 at the front abutment surface 81 of the rear portion 83, which peg is truncated because the sleeve 58 and the movable piston 22 are moving at substantially the same speed. It does not engage the conical groove 80.

Therefore, when the driver releases the braking force, the key 60 neither locks the sleeve 58 nor resists the back and forth movement of the movable piston 22.

On the other hand, when the driver moves the control rod 38 at an abruptness corresponding to the emergency braking condition, the movable piston 22 moves rather than the movable piston 22 due to the delay caused by the equilibrium of the pressure in the rear chamber 18. Quickly, the plunger 46 moves forward. As a result, upon rocking of the key 60, the peg 78 moves away from the front abutment surface 81, into the groove 80 and abuts the shoulder forming surface 76 for precise axial locking of the sleeve 58. Slide in the groove.

However, when the driver releases some braking force, the key 60 locks the sleeve 58 and then the finger 52, allowing the movable piston 2 to move independently of the position of the plunger 46.
Resist 2 return movements. Such a position ensures that the maximum braking force on the piston 22 is maintained.

When the driver releases the braking force considerably, the return movement of the control rod 38 causes the plunger 4 to move.
6 drives its pin 71 to bias the vertical branch 82 of the key 60 back and forth, causing the key 60 to be unlocked. Moreover, the return of the plunger 46 causes the three-way valve 50 to open. The re-evacuation of the rear chamber 18 causes the piston 22 to move, so that the horizontal branch 84 of the key is guided in the piston 22 between the rear wall 66 and the front wall 68 of the cavity 62, so that the key 60 is in its position. Returned to rest position.

In such a servo motor 10, the sleeve 5 to which the finger 52 is attached
In the rest position, as shown in FIG.
It is provided so that a predetermined gap "J ₁ " may exist between and.

The size of the gap “J ₁ ” determines the auxiliary force actually supplied by the movable piston 22, with respect to which the reaction force is from the movable piston 22 to the reaction disc 32.
Is transmitted to the control rod 38 via. The magnitude of the assisting force is commonly referred to as the "jump" of the servomotor 10, which depends on the dimensions of the fingers 52, and in particular the axial thickness "H ₁ " of the fingers 52 as shown in FIG. Due to

Moreover, in this servomotor 10, the axial position of the locking element-forming rear lateral surface 76 of the sleeve 58 will be uniform when an input is applied to the control rod 38 at a speed higher than a predetermined speed. The condition is the speed at which the directional clutch device 56 is about to start. In fact, as long as the peg 78 of the key 60 is retained by the front abutment surface 81 of the rear portion 83, the peg will not enter the groove 80 and the one-way clutch device 56 will remain inactive.

The speed is commonly known as “light speed”, and as shown in FIG. 4, this speed is therefore determined by the predetermined dimensions of the sleeve, and more particularly the plunger during forward movement of the plunger. The rear surface 100 of the finger at the bottom of the hole 102 in the sleeve 58 against which the front lateral end 59 of 46 abuts and the shoulder forming lateral surface 76 of the sleeve 58.
Due to the axial distance H ₂ between and.

Conventionally, the sleeve 58 is manufactured using a shaping lathe to obtain the correct dimensions H ₁ and H ₂ suitable for the acoustic performance of the servomotor 10.

This design has the disadvantage of significantly increasing the cost of the sleeve as it must comply with the exact dimensions of the sleeve during manufacture and additionally requires unit inspection of the sleeve 58.

To address this difficulty, the present invention provides a sleeve 58 whose dimensions can be adjusted simply by a plastic deformation process.

Thus, the sleeve 58 comprises a first adjusting portion located between the front and rear surfaces of the finger 52 and a second adjusting portion located between the rear surface 100 of the finger 52 and the rear lateral surface 76.
An adjusting portion, both of which are plastically deformable at least axially so that the servomotor 10 can be adjusted before assembly.

For this purpose, according to the invention, the front part 79 is provided on the rear surface 10 of the finger 52.
It includes an inner annular flange 104 which projects from 0 and extends rearward, said flange forming a first adjusting part for adjusting the position or jump of the servomotor 10 with which the finger 52 biases the reaction disc 32. It can be deformed in the axial direction before assembly.

Moreover, the front portion 79 and the rear portion 83 of the sleeve 58 have a reduced thickness "e".
Are separated by an intermediate portion 106 which has a second adjustment portion for adjusting the comfortable position of the peg 78 of the key 60 against the locking rear lateral surface 76. It is deformable in the axial direction.

In view of this object, the sleeve 58 is made of a material exhibiting a low elastic limit and high toughness and is specifically designed to plastically deform the sleeve 58, as shown in FIG.
It is transformed at 08.

The facility 108 includes a tubular, coaxial male 110 and female 112 with a sleeve 58 disposed between the molds and deformed in a single axial compression deformation process,
Here, the molds 110 and 112 are axially pressed together to simultaneously obtain the predetermined required dimensions "H ₁ " and "H ₂ " for the first and second adjusting parts.

More specifically, the inner diameter D _i 112 of the tubular female mold 112 _allows the sleeve 58 to
It is larger than the outer diameter _De83 of the rear portion 83 of the sleeve 58 for housing in 12. The female mold 112 includes a rear lateral wall 114 with a cylindrical bearing surface 116 extending in a forward direction, in which the front end 118 of the cylindrical bearing surface 116 extends to the sleeve 5.
The sleeve 58 is fitted to the annular flange 104 of the eight in a resting manner.

The male mold 110 includes a hole 120 whose diameter matches the outer diameter _De 79 of the front portion 79 of the sleeve 58. The front lateral bottom portion 122 of the hole 120 has a sleeve 58.
It supports the front lateral wall 59 of the front portion 79 of the.

The male mold 110 is a convex cylindrical shape that projects rearwardly and is designed to receive an adjustment shim 126 of a predetermined length “L ₁₂₆ ”, which is continuously disposed in the tubular female mold 112. It includes a support surface 124.

The installation 108 includes a pressurized front tubular spacer 128 mounted on the sleeve 58 and axially contacting the shoulder forming lateral surface 76 of the sleeve 58, and a second length having a predetermined length “L _{13 0} ”. Including a posterior tubular adjustment shim 130, both the spacer and the shim, of the female 112 between the female cylindrical support surface 116 and its inner cylindrical wall 132 prior to the axial compression deformation process. Provide fittings inside.

Therefore, the tubular shims 126 and 130 are, depending on the type of servomotor involved,
It can be exchanged to obtain different values of dimensions "H ₁ " and "H ₂ ".

In this configuration, the required dimension “H ₁ ” is given by the relation H ₁ = L _110/1 + L ₁₂₆ −L _112/1 (R1), where L _110/1 is the first Refers to the dimension of the mold 110 between its shoulder against which the tubular shim 126 abuts and the front lateral bottom 122, L _112/1 being the first
Refers to the dimension of the mold 112 between its front end 134 against which the tubular shim 126 abuts and the front end 118 of the cylindrical support surface 116.

Similarly, the required dimension “H ₂ ” is given by the relation H ₂ = L _112/2 −L ₁₃₀ −L ₁₂₈ (R2), where L _112/2 is the cylindrical bearing surface. Refers to the dimension of the mold 112 between the front end 118 of 116 and the posterior lateral wall 114, and L ₁₂₈ refers to the length of the spacer.

Therefore, as can be seen in FIG. 5, the required dimensions H ₁ and H ₂ are directly dependent on the length of the tubular shims 126 and 130.

Typically, during the deformation process, each of the initial dimensions H ₁ and H ₂ is reduced by 0-0.5 mm.

Finally, regarding the deformation of the sleeve 58, the male mold 110 is fixed and the female mold 112 is
It is mounted so as to be slidable in the axial direction so that it is pressed toward the male mold 110 with a predetermined compressive force F. The direction of the compressive force F and its point of action are shown in FIG.

Thus, in a beneficial way, the invention provides a low-cost, maximum-brake-force benefit in emergency braking situations, even if the driver's behavior may be accompanied by a strong depression of the brakes. A servo motor 10 is provided.

[Brief description of drawings]

[Figure 1]   1 is an overall view of a pneumatic servomotor according to the prior art.

FIG. 2 is a detailed axial sectional view showing a pneumatic servomotor for auxiliary braking according to the present invention in a non-actuated position of a one-way clutch device.

FIG. 3 is a detailed axial sectional view showing a pneumatic servomotor for auxiliary braking according to the present invention in an operating position of a one-way clutch device.

FIG. 4 is an axial cross-sectional view showing a sleeve for the one-way clutch device of FIGS.

[Figure 5]   FIG. 4 is an axial cross-sectional view of the equipment for plastic deformation of the sleeve according to FIG. 3.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW F term (reference) 3D048 BB21 CC26 EE09 EE15 EE25                 4E087 CA14 EC13 HB05

Claims (17)

[Claims] 1. A rigid casing (12) is included, in which a transverse bulkhead (14) is movable, a front chamber (16) under a first engine negative pressure (P ₁ ) and an engine negative pressure. It is a type that defines a second pressure which varies between the atmospheric pressure (P _a) (P ₂₎ rear chamber under a (18) in a gastight manner; move with the partition wall integrally with the movable partition wall (14) Control rod (38) with movable piston (22) and return spring (40)
A control rod (38) that selectively moves within the piston (22) as a function of the axial input exerted in the forward direction against the return force exerted on the control rod (38). Is biased towards an intermediate drive position or an end drive position resulting from applying an input at a predetermined high speed; disposed in the piston (22) at the front portion of the control rod (38). Plunger (46) and plunger (4
A three-way valve (50) including at least an annular valve seat (48) supported in the rear portion of 6)
And a three-way valve which connects the anterior chamber (16) to the posterior chamber (18), especially when the control rod (38) is in the rest position, or the control rod (
38) is a type in which the second pressure (P ₂ ) in the rear chamber (18) can be changed by gradually connecting the rear chamber (18) to the atmospheric pressure (P _a ) when driven. The rear surface of the finger (52) slidably fitted to the front end of the plunger (46) in the end drive position of the control rod (38) has the plunger (46)
), The front surface of the finger (52) contacts a reaction disk (32) integral with the movable piston (22), and the reaction force of the movable piston (22) is transferred to the plunger (22).
46) and control rod (38); and plunger (46
) At least one coaxial tubular sleeve (58) sliding on and provided with fingers (52) at the front end, a non-actuated position and the drive of the control rod (38) not cooperating with the sleeve (58); A one-way clutch device (56) including a latching element (60) movable to and from an actuated position controlled position.
The latch element cooperates with the locking element (76) of the sleeve (58) to cooperate with the finger (5
2) the movable piston (46) independent of the plunger (46) and the control rod (38).
22) In a pneumatic servomotor (10) for auxiliary braking of a motor vehicle of the type in which this sleeve is locked in the front end axial position so as to lock 22), the sleeve (58) is connected to the front surface of the finger (52). It includes a first adjusting portion (104) located between the rear surfaces and a second adjusting portion (106) located between the rear surface of the fingers (52) and the locking element (76), said two parts. However, the pneumatic servomotor is plastically deformable at least in the axial direction so that the servomotor (10) can be adjusted before assembly. 2. A pneumatic servomotor (10) according to claim 1, wherein the latching element comprises a substantially annular key (60) surrounding a sleeve (58) with a predetermined clearance, the key being the key. Is driven by the movable piston (22) when an input is applied at a predetermined speed, and the peg (78) of the key (60) constitutes a locking element (
58) A servo motor which can be swung about a substantially lateral axis so as to come into contact with the rear lateral surface (76) of 58). 3. The servomotor (10) according to claim 2, wherein the sleeve (58) comprises a tubular front cylindrical portion (79) which at the end constitutes a finger (52) and a front portion (79).
Radial grooves (80 having a diameter _{(D E79)} substantially larger in diameter than _{(D e83)} of
And a tubular posterior cylindrical portion (83) including a groove shoulder forming anterior lateral surface (83).
76) A servo motor characterized in that the lock rear lateral surface is provided. 4. Servo motor (10) according to claim 3, wherein the front portion (79) projects from the rear surface (100) of the finger (52) and extends rearwardly.
), Axially prior to assembly such that the flange constitutes a first adjusting portion for adjusting the position or jump of the servomotor (10) with which the finger (52) biases the recoil disc (32). A servo motor, which can be transformed into 5. A servomotor (10) according to claim 3 or 4, wherein the front portion of the sleeve (
79) and the rear portion (83) have an intermediate portion (106) with a reduced thickness (e).
And an intermediate portion of the shaft to form a second adjusting portion for adjusting the light position of the peg (78) of the key (60) against the rear locking lateral surface (76). A servo motor characterized by being deformable in any direction. 6. The servomotor (10) according to any one of claims 3 to 5, wherein the groove (80) is substantially frustoconical in shape behind the shoulder forming front lateral surface (76). Servo motor characterized by exhibiting. 7. The servomotor (10) according to claim 6, wherein the peg (78) is a sleeve (10).
Servo motor, characterized in that it has the shape of a concave frustoconical angular sector that complements the frustoconical contour of the groove (80) in 58). 8. A servomotor (10) according to any one of claims 2 to 7, wherein the key (60) has the shape of a tee in an axial cross-section, the vertical branch (82) thereof. Are oriented substantially radially and are traversed by a sleeve (58), while their substantially horizontal oriented branch (84) is perpendicular to the axis (A) of the piston. The void (6) is housed with no axial gap between two opposing walls (66, 68) of the void (62) across the (22).
2) A servomotor which allows the swinging movement of the key (60) within. 9. The servomotor (10) according to claim 8, wherein the front horizontal half-branch (86) of the tee-shaped key (60) faces the sleeve (58) radially and the peg (7).
8) A servomotor having a protruding surface. 10. The servo motor (10) according to claim 9, wherein the tee-shaped key (60) is
A blind hole (96) for centering the tee-shaped key (60) on both sides of the sleeve (58) on the vertical branch (82) of the tee and a front lateral wall (68) of the cavity (62).
) And two compression springs (94, 95) arranged between
2) A servomotor which is elastically biased with respect to the rear lateral wall (66). 11. The servomotor (10) according to claim 1, wherein:
A servomotor, wherein the sleeve (58) is made of a material exhibiting a low elastic limit and high toughness. 12. An installation (108) for plastic deformation of a tubular sleeve (58) used in a pneumatic servomotor (10) for auxiliary braking according to claim 1, comprising:
A predetermined outer diameter (D _e79 ) closed at its end by a front transverse wall (100) extending a _{deformable coaxial} annular flange (104) forming a first adjusting portion towards the inner part of the sleeve. ) Tubular front cylindrical portion (79) and front portion (79)
A deformable intermediate portion (106) having the same outer diameter as the second adjustment portion and a predetermined diameter (D _e83 ) larger than the diameter (D _e79 ) of the front portion (79) and at least one Tubular posterior cylindrical portion (83) including shoulder forming posterior lateral surface (76)
An apparatus comprising a tubular coaxial male (110) and a female (112), wherein a sleeve (58) is disposed between the molds to provide a single axial direction. It is deformed in a compression deformation process, in which the molds (110, 112) simultaneously obtain the predetermined required dimensions (H ₁ , H ₂ ) for the first and second adjusting parts (104, 106). Equipment characterized by being axially pressurized together. 13. The equipment of claim 12, wherein (108), larger than the outer diameter of the rear portion of the inside diameter _{(D I112)} sleeve (58) of the tubular female die (112) _{(D e83),} female (112) has a rear lateral wall (11) with a cylindrical bearing surface (116) extending in a forward direction.
4) in which the front end (118) of the cylindrical bearing surface is sleeve (5
8) A facility in which the sleeve (58) is fitted so as to rest on the annular flange (104). 14. The installation (108) according to claim 12 or 13, wherein the male mold (110) has a diameter (D _e79 ) corresponding to the outer diameter (D _e79 ) of the front portion (79) of the sleeve (58). 1
20) and an anterior lateral bottom (122) supporting the anterior lateral wall of the anterior portion (79) of the sleeve (58). 15. The equipment (108) according to claim 13 or 14, wherein the male mold (110) projects rearward and is continuously arranged in the tubular female mold (112) by a predetermined length (L). ₁₂₆ )
An installation comprising a convex cylindrical bearing surface (124) designed to receive the first tubular adjustment shim (126) of the. 16. The installation (108) according to any one of claims 13 to 15, wherein the installation is attached to the sleeve (58) and the shoulder forming lateral surface (7) of the sleeve (58).
6) includes a pressurized front tubular spacer (128) in axial contact with a second rear tubular adjustment shim (130) having a predetermined length (L ₁₃₀ ), both spacer and shim Prior to the axial compression deformation step, providing a fixture within the female mold (112) between the female cylindrical support surface (116) and its inner cylindrical wall (132), Equipment to do. 17. The installation (108) according to any one of claims 12 to 16, wherein the male mold (110) is fixed and the female mold (112) has a predetermined value of compressive force (F). Male type (1
An equipment characterized by being mounted slidably in the axial direction so as to be pressed toward 10).