MXPA06007402A - Method for assembly of a pneumatic servo - Google Patents

Abstract

The invention relates to an assembly device (100) for a pneumatic servo (200). A cover (203) for the servo is housed in a support (101). A cylindrical cap (104), the internal volume (107) of which is greater than the cylinder volume (206) of the servo covers the cylinder placed on the cover. A gear system (110) on the device rotates two sets of rollers (109A and 109B) around the servo. An eccentric (118), controlled by the gear system, permits an oscillating movement of the rollers against a wall of the servo. The crimping is achieved by means of alternating application of the rollers. An angle of attack for the first rollers is greater than an angle of attack for the second rollers. The invention further relates to a method for crimping a servo and such a servo.

Description

ASSEMBLY METHOD OF A PNEUMATIC SERVOMOTOR FIELD OF THE INVENTION The invention relates to a device for assembling a pneumatic servomotor of a braking device of a motor vehicle. More precisely, the invention relates to a device for making it possible to securely attach a tire and a cylinder of a pneumatic servomotor. The invention also relates to a method for making possible the assembly of the cylinder and the cover by using the device of the invention. The invention finally relates to a pneumatic servomotor.

An object of the invention is to provide a servomotor that can be used safely in a braking device. Another object of the invention is to prevent disassembly of the servomotor during its use, without thinking about the consequences of the thickness of a metal sheet forming the servomotor. A further object of the invention is to provide a servomotor that is light in weight, without its resistance being affected.

BACKGROUND OF THE INVENTION In a braking device of a motor vehicle, a servomotor can be mounted between a braking control and a master cylinder. The pneumatic servomotor has the role of amplifying a force in the braking control, so that a hydraulic pressure in the master cylinder is greater.

A servomotor can be supplied with a housing in a generally cylindrical shape. The housing is formed of a cylinder and a cover. The cylinder and cover are fixedly attached to each other. A front camera and a rear camera are placed in an internal volume of the housing. The front camera is directed towards the master cylinder and has a variable volume. The rear camera, also with a variable volume, is directed towards the braking control. The front camera is separated from the rear camera by a movable partition. The movable division is formed by a flexible and sealed membrane and by a rigid skirt plate. The front chamber is pneumatically connected to a vacuum source. The rear chamber is pneumatically connected, in a controlled manner by a valve to a source of propellant fluid. A braking control drives a servomotor control rod. The actuation of the rod controls the opening of the valve and an influx of fluid in the rear chamber. The pressure change that results from them causes a rigid skirt plate movement.

During braking, the torsional forces exerted on the servomotor location are extremely large. Specifically, the servo motor chambers are subject to sudden changes in pressure. In particular, during braking, air is allowed in the rear chamber. This air inlet drives the movable division towards the front camera. Since the servomotor housing is made of two originally dependent parts, it is essential that these two parts are firmly fixed together. Therefore it is necessary that the contract between the cover and the cylinder is sufficient, so that during braking and more precisely during the propulsion of the skirt plate, the cylinder does not twist out of the cover.

In order to ensure that the cover was properly attached to the cylinder, a dot pattern is actually carried out at an outer periphery of the walls of the cover and the cylinder. He "dotted" means stamping at localized points. To hold the cylinder firmly in the cover, these stamping points are evenly distributed over the entire outer periphery of the housing. So far, said assembly has been sufficient.

However, for some time, the search has been reduced to the servomotor weight. Specifically, the servomotor and more precisely the servomotor housing is formed of metal foil walls. A thickness of the metal sheet and a shape of the servomotor therefore has an effect on its weight. The search in particular is to reduce the weight of the servomotor by reducing the thickness of the metal sheet that forms the housing. The thickness and shape of the servomotor have been modified to obtain a minimum weight. "Minimum weight" means the lowest weight of the servomotor in which the same stiffness and the same resistance are twisted as a conventional servomotor is obtained.

However, the braking resistance at the junction location between the cover and the cylinder is reduced. A dot pattern of the cover with the cylinder therefore does not provide complete satisfaction when the thickness of the metal sheet is greatly reduced.

SUMMARY OF THE INVENTION The invention particularly notes to solve this problem by providing a servomotor whose thickness and shape can be modified to obtain a minimum weight. The servomotor obtained in such a manner has a high torsional strength including at the location of the junction between the cover and the housing cylinder.

Therefore, the invention proposes a device for assembling a servomotor and more precisely a cover and a cylinder of a servomotor housing. The assembly device of the invention allows a continuous stamping on the entire outer periphery of the housing, the cylinder and the cover. The continuous printing makes it possible to obtain a strong hold of two parts, one on the other. The contact zone offers better resistance to torsional forces.

To achieve said continuous stamping, the device of the invention is provided with at least one set of rollers. The rollers are rotated near the servomotor. The rollers come into contact with the servomotor at the location of the junction between the cover and the housing cylinder. The rollers, when they pass, bend one end of a sheet of metal forming the wall of the cylinder around one end of a sheet of metal forming the wall of the cover. In a particular exemplary embodiment of the invention, the device is provided with two different sets of rollers. The first set of rollers makes it possible to fold the end of the metal sheet forming the wall of the cylinder around the end of the metal sheet forming the wall of the cover, at a first angle. The second set of rollers, meanwhile, makes it possible to bend the metal sheet of the cylinder at a second angle more acute than the first. A roller of the second set of rollers is not pressed against the outer wall of the housing until a roller of the first set of rollers has been first passed.

In addition, the rollers of the first set of rollers are for bending the sheet metal of the cylinder. The first folding action makes it possible to fold an initial position parallel to an axis of rotation of the device, the metal sheet by thirty to sixty degrees. The metal sheet is also partially pushed in towards the center of the servomotor. An initial position of the end of the cover wall is perpendicular to the end of the cylinder wall. "Initial position" means the position in which the cover and cylinder are placed one on top of the other, but do not join with one another. After passing at least one roller of the first set of rollers, the metal sheet of the cylinder is bent again in the direction of the metal sheet of the cover, which is stamped slightly. A roller of the second set of rollers is then pressed against the metal sheet of the housing, wherein the first roller passes to further bend the metal sheet of the cylinder against the metal sheet of the cover. Ideally, the metal sheet of the cylinder bends ninety degrees after the rollers of the second set of rollers has been passed.

The roller set of the device of the invention, for example, is provided with three rollers each. The rollers of the first set alternate with the rollers of the second set. For a generally circular cylindrical mounting device, the rollers are distributed evenly over a complete perimeter of the device. Furthermore, for example, a roller of the first set is separated by 120 ° from the other roller of the first set. A roller of the first set is separated by 60 ° from a roller of the second set. In this way the stamping is carried out in two successive stages, the rollers of the second set should be pressed against the wall of the housing only in the locations where the rollers of the first set have already passed. Therefore, in addition to a rotational movement of the rollers near the servomotor, each of the rollers is forced to make an alternating radial movement relative to the servomotor. Said oscillating movement is made possible by an eccentric mechanism of the assembly device. The rollers of the two sets are angularly out of phase one with another. However, the rollers of one and the same set are angularly in phase. In addition, the rollers of the first set and then the rollers of the second set are brought alternately towards the center of the servomotor. This is how a continuous stamping is obtained in the servomotor housing in one or more complete rotations of the rollers near the servomotor.

The invention also proposes a method of assembling the servomotor housing.

The method of the invention makes it possible to emboss the cover and the housing cylinder in a continuous manner over the entire outer perimeter of the housing.

The object of the invention is therefore a pneumatic servomotor for a braking device of a motor vehicle, characterized in that a cover and a cylinder of said servomotor are connected to one another over a complete external contour.

A further object of the invention is a device for assembling a pneumatic servomotor, characterized in that it comprises a fixed cylindrical support whose internal volume is greater than the volume of a servomotor cover, the cover being housed in the support, a cylindrical cover whose internal volume is greater than the volume of the servomotor cylinder, said cover imposing an axial load on the cylinder, at least one set of rollers, rotated by a motor, the rollers rotating at least partially near the support. A further object of the invention is a method for stamping a servomotor, characterized in that it comprises the stages of a cover of a servomotor inserted into a support of a stamping device, an upper end of a wall of the cover resting on the end upper of an internal wall of the support, a cylinder of the servo-motor is placed on the cover, a lower end of a cylinder wall resting on the upper end of the cover wall, a cover of the embossing device is placed on the support, a lower end of the cap compressing the lower end of the cylinder wall at the upper end of the cover wall, a motor is driven, - the stamping rollers are rotated near the servomotor, by means of the motor, the end The lower wall of the cylinder is continuously printed on the upper end of the wall of the cover.

BRIEF DESCRIPTION OF THE FIGURES The invention will be better understood from reading the following description and in the examination of the figures that accompany it. The latter are provided as an indication and not as a way to limit the invention. The figures represent: Figure 1 is a longitudinal section of the servomotor housed in an assembly device of the invention.

Figures 2 and 2A, are an extension of Figure 1 in the location of a connection between a cover and a cylinder of the servomotor and a roller of the invention.

Figure 3 is a cross section of an assembly device of the invention. DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows an exemplary embodiment of a device 100 for the assembly of the servomotor 200. The device 100 is provided with a fixed support 101. In the example shown in Figure 1, the support 101 has a generally shape cylindrical An internal volume 102 of the support 101 is such that it is possible to insert therein a rear portion 201 of the servomotor 200. The "rear portion 201 of the servomotor 200" means a control rod 202 and the cover 203 of the servomotor 200. The cover 203 It also has a generally cylindrical shape.

A 2004 end of a wall 205 forming the cover 203 rests on an upper end 105 of a central positioner 106. The central positioner 106 is, for example, generally ring-shaped. A diameter of the ring 106 is approximately equal to an internal diameter of the support 101 at the location of an upper end 103 of the support 101. In addition, the central positioner 106 is placed on an internal perimeter of the support 101 at the location of an upper end 103 The central positioner 106 makes it possible to ensure a good position for the cover 203. "Good position of the cover 203 on the support 101" means a position that allows the device 100 to be successfully assembled to the servomotor 200.

In another example mode, the central positioner 106 consists of at least two different parts. In addition, the central positioner 106 does not completely follow the internal contour of the support 101. It can move uniformly, at different points in the internal diameter of the support 101. The various elements forming the central positioner 106 further. they make it possible to support the cover 203 at certain points and to center it. In another embodiment, it is also possible to not use the central positioner 106. The cover 203 then rests directly on the support 101, at the location of the upper end 103 of said support 101.

Once the cover 203 has been placed inside the support 102 of the support 101, a cylinder 206 of the servomotor 200 is placed. The cylinder 206 forms a front portion of the servomotor 200. The cylinder 206 has a generally cylindrical shape. The cylinder 206 is placed on the cover 203 so that one end 208 of a wall 209 forming the cylinder 206 rests on the end 204 of the cover 203. In the example shown in Figure 1, an end 211 of a sealing membrane 210 of the servomotor 200 forms a fold 211. The fold 211 is trapped between the ends 204 and 208 respectively of the cover 203 of the cylinder. 206. The fold 211 in particular provides a seal at the contact location between the cover 203 and the cylinder 206.

A cover 104 of the assembly device 100 is subsequently placed in the holder 101. The cap 104 generally cylindrical in shape. An internal volume 107 of the lid 104 is such that the cylinder 206 can be accommodated there. A first end 108 of the cover 104 rests against the end 208 of the wall 209 of the cylinder 206. "First end" means in the description the end directed to the left in the figure. Colloquially, "second end" means in the description the end directed to the right in the figure. The end 108 of the cover 104 is subsequently pressed in a direction D at the end 208 of the cylinder 102. This imposes an axial load on the location of the connection between the cover 203 and the cylinder 206. The fold 211 is compressed between the two walls 205 and 209 at the location of their ends, respectively 204 and 208.

The rollers 109 (two rollers visible in Figure 1) are placed on an outer periphery of the support 101. Figure 3 shows more precisely the arrangement of the rollers 109 of the device 100. The rollers 109 are six in number. The rollers 109A of a first set inter-spaced with the rollers 109B of a second set. The rollers 109 are placed uniformly on the total periphery of the support 101.

Figure 1 shows that the rollers are in contact with the servomotor 200 at the location of the connection between the cover 203 and the cylinder 206.

Figures 2 and 2A show two elongations, respectively an elongation of Figure 1 at the contact location between a roller 109A and servomotor 200 and at the contact location between a roller 109B and servomotor 200. In both cases, it can be observed that the end 204 of the cover 203 rests on the upper end 105 of the central positioner 106. Similarly, the fold 211 of the sealing membrane 210 compressed between the end 204 of the cover 203 and the end 208 of the cylinder 206 can be observed. The end 208 of the cylinder 206 is compressed by the end 108 of the cap 104. The end 208 of the cylinder 206 is compressed by the end 108 of the cap 104. The end 208 of the cylinder 206 is approximately parallel to an axis of rotation of the positioner central 106. End 204 of cover 203, on the other hand, is perpendicular to end 208. End 208 extends to the right of Figure 2 beyond a point of contact with end 204.

In the invention, the end 208 can be bent around the end 204 and the fold 211 in such a way that the end 208 is ideally perpendicular to the axis of the central positioner 106. The desire is to achieve said bending over the entire periphery of the servomotor 200.

Therefore, as shown in Figure 1, the assembly device 100 is provided with a coupling element 110 by rotating the rollers 109 all near the servomotor 200. The coupling element itself is rotated by a motor (not shown) . The coupling element 110 is provided with two gear wheels 111 and 112. The wheels 111 and 112 have a different number of teeth.

By means of the first wheel 111, the coupling element 110 rotates the complete set of rollers 109A and 109B near the servomotor 200. The second coupling wheel 112 rotates an eccentric 118 imposing a periodic sinusoidal movement on the rollers 109. Furthermore, for By means of this eccentric 118, the rollers 109 are not pressed continuously against the walls 205 and 209 of the servomotor 200.

When the assembly device 100 is placed in motion, the rollers 109 continuously rotate all near the servo motor 200 and are pressed radially against the walls 205 and 209 of the servo motor 200 in a periodic intermittent manner. The of rollers 109A and 109B are angularly out of phase. The angular array out of phase is such that it allows a pressure of the rollers 109A against the wall of the servomotor 200 to alternate with a pressure of the rollers 109B.

To achieve a good stamping, the desire is to press the rollers 109A radially against the servomotor 200 before the rollers 109B. Specifically, the rollers 109A and 109B differ from one another in their angles of attack. Figures 2 and 2A show that the rollers 109 and 109B are all provided respectively with a bevel 113A and 113B. A beveled cut forming the bevels 113A and 113B is made on an upper face of the rollers 109A and 109B. The shape of the bevels 113A and 113B is different. Specifically, an angle of attack 114A of the bevel 113A is greater than the angle of attack 114B of the bevel 113B. "Angle of attack" means the angle formed by the beveled cut of the bevels 113.

A first contact between the roller 109A and the end 208 of the wall 209 of the cylinder 206 makes it possible to slightly bend the end 208 in the direction of an axis C of the support 101. The roller 109B is then pressed against the end 208 which has already partially folded Since the angle of attack 114B is smaller than the angle of attack 114A, it is possible to bend the end 208 slightly more in the direction of the axis C.

For example, the angle of attack 114A falls between 115 ° and 135 °. The angle of attack 114B, on the other hand, falls between 80 ° and 90 °. In a preferred example, the angle of attack 114A is 120 °. In addition, the end 208 bends 60 ° during the passage of the roller 109A. Then, during the passage of the roller 109B, the end 208 is bent an additional 25 °. Finally, the end 208 is virtually perpendicular to the axis of the central positioner 106. The end 208 stamps the end 104 while catching the fold 211.

In the invention, said stamping operation is performed over the entire periphery of servomotor 200. Device 100 makes as many rotations around servomotor 200 as are necessary for cylinder 206 to join cover 203.

Figure 1 shows a particular exemplary embodiment of the device that makes it possible to rotate the rollers 109 and impart thereto a radially oscillatory movement relative to an axis C of the support 101.

The gear wheel 111 of the coupling element 110 rotates a pinion 115. A body 116 is attached to the pinion 115. The body 116 is therefore rotated by the rotation of the wheel 111. The body 116 is furthermore rotated all around the support 101. The wheel 112 of the coupling element 110 rotates a pinion 117. The pinion 117 joins freely in rotation to the body 116. In addition, the pinion 117 rotates independently of the body 116. The rotations of the body 116 and the pinion 117 depend respectively on the rotation of the wheel 111 and the wheel 112 of the coupling element 110. The number of teeth of the wheel 111 is different from the number of teeth of the wheel 112. The body 116 and the pinion 117 therefore do not rotate therein. speed. The pinion 117 rotates the eccentric 118 by means of a pinion 119. The eccentric 118 at least partially follows an internal periphery of the body 116.

The rollers 109 are mounted on an upper end of the eccentric 118. The eccentric 118 is attached to the body 116. The rollers 109 are therefore all rotated near the servomotor 200. But since the eccentric 118 is also in contact with the pinion 117 , the pinion 117 imposes a radial movement of oscillation relative to the axis C of the support 101 in the eccentric 118 and the rollers 109.

This also gives a rotary movement of all the rollers 109 near the servomotor 200, a radial oscillation movement of each of the rollers 109 relative to the axis C of the support 101. The rollers are therefore pressed periodically against the wall of the servomotor 200 and then they are separated therefrom. The out-of-phase angular array between the rollers 109A and the rollers 109B makes it possible to press the rollers 109A first against the wall of the servomotor 200. The rollers 109B are pressed only after the rollers 109B have passed.

Claims (13)

1. A device for assembling a pneumatic servomotor characterized in that it comprises: a fixed cylindrical support whose internal volume is greater than the volume of a servomotor cover, the cover being housed in the support; a cylindrical cap whose internal volume is greater than the volume of a servomotor cylinder, said cap imposing an axial load on the cylinder, at least one set of rollers, rotated by a motor, the rollers rotating at least partially near the support.

2. The device according to claim 1, characterized in that it is supplied with a first set of rollers and a second set of rollers, the two sets of rollers rotating at least partially near the support.

3. The device according to one of claims 1 or 2, characterized in that it is supplied with a central positioner falling on an upper end of the fixed support, the cover falling on the central positioner, the central positioner having a ring shape, a diameter internal of the central positioner being approximately equal to a diameter of the servomotor cover.

4. The device according to one of claims 2 to 3, characterized in that the first and second rollers are alternating.

5. The device according to one of claims 2 to 4, characterized in that the first set of rollers is supplied with three rollers and in that the second set of rollers is provided with three rollers, the first rollers being spaced at 120 ° one of the another and being spaced 60 ° from the second rollers.

6. The device according to one of claims 2 to 5, characterized in that the first rollers are supplied with a bevel, said bevel having an angle of attack falling between 115 and 135 ° and in which the second rollers are each provided with a bevel, said bevel having an angle of attack falling between 80 and 90 °.

7. The device according to claim 6, characterized in that the angle of attack of the bevels of the first rollers is 120 ° and that the angle of attack of the bevels of the second rollers is 85 °.

8. The device according to one of claims 2 to 7, characterized in that it is supplied with a coupling element driving the rollers in rotation and in that the coupling element is supplied with two gear wheels, a number of teeth of one first gear wheel of the coupling element driving in rotation two sets of rollers near the servomotor, being different from a number of teeth of a second gear wheel of said coupling element, the second wheel imposing a radial movement by means of an eccentric of oscillation of the rollers relative to a support axis.

9. A stamping method of a servomotor, characterized in that it comprises the stages of a cover of a servomotor is inserted in a support of a stamping device, an upper end of a wall of the cover resting on the upper end of an inner wall of the support, a servomotor cylinder is placed on the cover, a lower end of a cylinder wall resting on the upper end of the cover wall, a cover of the embossing device is placed on the support, a lower end of the cover the lower end of the cylinder wall comprising at the upper end of the cover wall a motor being driven, the stamping rollers are rotated near the servomotor by means of the motor, - the lower end of the cylinder wall is stamped continuously at the top end of the cover wall.

10. The method according to claim 9, characterized in that it comprises the step - the rollers are made to perform the radially oscillating movement relative to an axis of the support.

11. The method according to claim 10, characterized in that the step comprises the rollers for performing the radial movement of oscillation relative to the axis of the support by means of an eccentric driven by a coupling element.

12. The method according to one of claims 9 to 11, characterized in that it comprises the step - the lower end of the cylinder wall is stamped on the upper end of the cover wall by successfully applying the provided rolls with a first angle of attack and the rollers provided with a second angle of attack, the first angle of attack being greater than the second angle of attack.

13. The pneumatic servomotor for an automotive vehicle braking device, characterized in that it is obtained by a method according to one of claims 9 to 12.