JP5303468B2 - Mechanical tappets, especially for internal combustion engine fuel pumps - Google Patents

Abstract

A mechanical tappet (101, 201, 301, 401, 501, 601, 701, 801, 901, 1001) is proposed, in particular for the reciprocal actuation of a pump piston (39) of a fuel pump of an internal combustion engine, having a sleeve-shaped tappet housing (102, 202, 302, 402, 502, 602, 702, 902, 1002) which is configured as a sheet metal moulding and having a rotationally mounted drive roller (6). Here, a pin (4) which mounts the drive roller centrally is to be provided, wherein end sections (7) of the pin which protrude from the drive roller are supported in pin eyelets (8) of the tappet housing.

Description

  The present invention relates to a mechanical tappet for lift operation of a pump piston, particularly in a fuel pump of an internal combustion engine. The tappet includes a bush-shaped tappet housing. The tappet housing is configured as a sheet metal working part and is installed for movement in the longitudinal (longitudinal) direction within the tappet guide by a substantially cylindrical outer peripheral surface. The tappet further includes a drive roller rotatably installed and a lift transmission element. The lift transmission element is made separately from the tappet housing and is inserted into the tappet housing and has a contact surface for the pump piston on the power take-off side.

(Background of the Invention)
The aforementioned type of tappet is disclosed in the general document DE10345089A1. The tappet proposed in this document functions as an operating element of a high-pressure fuel pump known per se for the transmission without a lateral force of the cam lift to the pump piston and is configured as a sheet metal working part. A bush-shaped tappet housing. Compared to the generally extruded tappet housing of such roller tappets, this tappet housing has the potential for high weight and considerable cost savings. The person skilled in the art is very clear of these advantageous properties by comparing the tappets proposed in the above-mentioned literature with tappets which are extruded and thus have a thick-walled tappet housing, as disclosed in DE 197 29 793 A1. Can understand.

  Nevertheless, the tappet proposed in the first document has some serious drawbacks associated with the drive roller. One of these significant drawbacks is that the drive roller is mounted without a heart in the lift transmission element inserted into the tappet housing, so that the drive roller has a corresponding recess in the lift transmission element on its peripheral surface. To slide inside. However, as is well known, such mounting of the drive roller is very difficult to adjust. Because, under all operating conditions of the internal combustion engine or fuel pump, the desired rotation of the drive roller is guaranteed only if the contact friction between the cam and the drive roller is greater than the contact friction between the drive roller and the lift transmission element Because it can be done. Drives that interfere with the actual purpose of friction reduction and are associated with a high risk of contact wear between the drive roller and the cam and / or between the drive roller and the lift transmission element if sufficient matching of the contact partners is not achieved At least occasional outages of the rollers are expected. Also, with such a centerless attachment of the drive roller in the lift transmission element, it is necessary to take sufficient measures to ensure an inseparable fixing of the drive roller on the tappet.

(Object of the present invention)
The object of the present invention is therefore to improve a tappet of the aforementioned type so that the above-mentioned drawbacks are eliminated by simple means. Tappets must not only have high light weight and potential for cost savings, but also require the lowest drive roller drive force while providing the highest operational reliability .

(Disclosure of the Invention)
The present invention achieves the above object by the fact that the drive roller is attached to the center of the pin, optionally via a rolling element, and the end of the pin protruding from the drive roller is supported in the pin hole of the tappet housing. Achieve.

  The fact that the present invention proposes a lightweight sheet metal workpiece that can be manufactured economically, and at the same time, in contrast to the prior art, the drive roller is no longer eccentrically placed in the lift transmission element by its peripheral surface. Due to the fact that it is not centered by a pin supported in the tappet housing, the tappet has a particularly light weight and can be manufactured economically. The tappet also has rolling contact with the actuator cam. As a result, the required driving force is considerably reduced and the reliability of the operation is guaranteed. The pin, which is itself supported in the pin hole and serves to mount the roller, at the same time, functions as a cost neutral anti-loss device for the drive roller in the tappet.

  With respect to the term “sheet metal parts”, the tappet housing can be molded not only from sheet metal blanks, but also from sheet-like semi-finished products such as thin-walled tubes, for example, whether they contain vertical seams. Can be clearly stated.

  According to a further proposal of the invention, the lift transmission element can be made as a perforated (punched) part made of sheet metal or a perforated bent part. The sheet metal lift transmission element is not only a basis for further reducing the cost of manufacturing the tappet, but also the functional requirements of the tappet housing and the sheet material used for these two parts in the choice of material. Can be optimally matched and can optionally differ in having a suitable surface coating. Alternatively, using lift transmission elements made by other manufacturing methods, eg materials adapted to functional requirements, heat and / or surface treatment, extrusion, casting, sintering or plastic injection molding, etc. It is also possible to do.

  According to another feature of the invention, in the region of the pin hole, the tappet housing is a double wall, and the pin hole extends parallel to the outer peripheral surface of the tappet housing and is bent into the tappet housing. Located on the tongue of the housing. A tappet housing having such a configuration is particularly advantageous when the tappet housing has a completely cylindrical outer peripheral surface and the pin is fixed by positive engagement into the pin hole by caulking of the pin tip. . This is because, in this case, the deformation of the tongue resulting from caulking has no or little effect on the cylindrical shape of the tappet housing which is necessary for guiding into the tappet guide.

  According to yet another inventive feature, the tappet housing has a recess in which for the correct orientation of the drive roller within the tappet guide and thus to provide a drive roller parallel to the cam. The anti-rotation body also used in the projecting portion projects radially beyond the outer peripheral surface of the tappet housing.

  As an alternative to the fully cylindrical shape of the tappet housing, it is likewise possible to construct a tappet housing with a flat portion that is recessed radially from the cylinder in the region of the pin hole. From the viewpoint of the molding method, it is appropriate to make a flat portion by locally cutting a part of the cylindrical outer peripheral surface, and as a result, a substantially sickle-shaped gap is formed in the tappet housing by the flat portion. .

  Furthermore, the lift transmission element is configured as an insertion plate supported on the axial shoulder of the tappet housing in the direction of the drive roller, the axial shoulder being formed on the inner peripheral surface of the tappet housing by a flat part. A lift transmission element of this construction can be made particularly economically as a perforated part made of sheet metal, which can appropriately harden the edge layer.

  A particularly advantageous embodiment of the insertion plate is a finely drilled part. Due to the fact that the anti-rotation body that ensures the correct orientation of the tappet in the tappet guide is constituted by a protrusion integrally formed on the insertion plate and protruding through the recess of the tappet housing, , Enabling further cost reduction by strengthening its functions.

  According to another proposal of the invention, the insertion plate has a flat shape and is supported on the axial shoulder by two arcuate supports located on opposite sides. While the arcuate support functions as a reliable support for the insertion plate on the axial shoulder, the intermediate part between these arcuate supports and out of the arcuate shape is the inner circumference of the tappet housing. Creates a clearance to the surface and functions as a ventilator and oil return during the operation of the tappet.

  Alternatively, two opposing reinforced knees where the insertion plate is supported on the axial shoulder by raised ribs extending on two support portions located on opposite sides, and the insertion plate extends between the support portions The insertion plate may have a box shape so as to include

Such a stiffening of the flat insert plate can alternatively be achieved by constructing an insert plate having a tab shape surrounding the inner portion where the flat frame-like portion has a U-shaped cross section. This frame-like part is supported on the axial shoulder by two opposing supports. The axial shoulder is configured as the end face of a straight edge extending parallel to the gap, and has a high shape rigidity, and at the same time is supported by the axial shoulder with a weak contact pressure. The insertion plate has a U-shaped shape and is supported on the axial shoulder by two opposing supports having a U-shaped cross section, the axial shoulder being substantially complementary to the U-shaped cross section and It can also be achieved by an arcuate end surface extending parallel to the gap. With this support, especially corresponding to a rotating knuckle, alignment errors or deviations between the contact surface of the insertion plate and the pump piston, caused by part tolerances and causing edge loading under high pressure, are At least in the direction of rotation of the insertion plate, it can be compensated in a simple manner.

  Furthermore, the insertion plate is inserted into the tappet housing with a positive engagement with the aid of a loss prevention device extending to the inner peripheral surface of the tappet housing. In a first embodiment, the loss prevention device includes a washer for supporting the insertion ring and a knob-like protrusion for supporting the washer, preferably made by pushing out the inner peripheral surface of the tappet housing. . This embodiment not only provides the further possibility of saving the cost of manufacturing the tappet with a very inexpensive washer, but also the manufactured insert plate into a similarly manufactured tappet housing in a later manufacturing step. The inserted tappet manufacturing and assembly sequence provides considerable material selection freedom, independent of each other, for the insert plate and tappet housing. Furthermore, the loss prevention device that operates by positive engagement also provides a very limited angle-adjustable play effect of the insertion plate within the tappet housing. As a result, again, alignment errors or deviations between the contact surface and the pump piston caused by component tolerances can be compensated.

  In an alternative embodiment, the loss prevention device preferably includes protrusions made by caulking on the inner peripheral surface of the tappet housing and a recess formed in the insertion plate for receiving these protrusions. With respect to the tappet manufacturing and assembly sequence, the coking of the protrusions is suitably performed in the soft state of the tappet housing with the insert plate inserted therein. Alternatively, it is conceivable to caulk the protrusions in a hard state of the tappet housing. As a result, by subsequently attaching the insert plate to the tappet housing, as before, there are many degrees of freedom for material selection of the insert plate and tappet housing.

  According to a further preferred development of the invention, it is also possible to form the lift transmission element as a roller carrier supported by a pin. The roller carrier has a bottom including a contact surface and a side that forms an angle from the bottom to the pin and forms a U-shaped cross section in the direction of the pin. The end of the pin is consequently supported in both the pin hole and the side pin hole of the tappet housing. In this regard, the tappet housing pin holes and / or the side pin holes are the required size with respect to the pins so that the roller carrier is inserted into the tappet housing to pivot about or with the pins. Is particularly advantageous. With this device, the force acting on the drive roller is transmitted to the roller carrier via the pin and to the contact surface of the roller carrier on the pump piston, to the tappet housing via the pin and from now on. And the lateral component force transmitted to the tappet guide. Thus, considering only the transversal force transmitted, it is possible to form a tappet housing with a particularly thin wall and thus with a particularly light weight. Also, the swivel suspension of the roller carrier on the pin allows for at least partial compensation of deviations or alignment errors between the contact surface and the pump piston.

  In a first embodiment of a roller carrier suspended on a pin, the bottom has a substantially flat shape and the roller carrier includes a reinforced knee that extends laterally from the bottom to the side. A similarly high shape stiffness of the roller carrier can be achieved, alternatively if the bottom is made in a tab shape with a U-shaped cross section extending transverse to the direction of the pins.

  In addition, the side extends through the window of the tappet housing and engages behind the outside of the flat to achieve the greater width of the drive roller with the associated higher basic load rating and durability. Each window is formed at a transition between one of a cylindrical shape and a flat portion.

  The use of the tappet of the present invention is not intended to be limited to only the operating elements of the fuel pump, for example the related functions as in the case of mechanical tappets for operating gas exchange valves of internal combustion engines. It extends to elements having For this purpose, the contact surface is formed as a hemispherical cavity at the bottom and functions, for example, to receive the spherical end of a tappet push rod that is moved with the gas exchange valve.

  In a particularly preferred embodiment of the invention, the pin is axially secured by positive engagement into the pin hole by a radially enlarged end, the pin being centered over its entire length with a center hardness of at least 58 HRC. And the edges are enlarged by radial spot riveting. Radial spot riveting (a method known per se and described in more detail in the description of the example embodiments of the present invention) increases the brittleness of the pin whose center is hardened even in the region of its ends. Nevertheless, the pin can be suitably shaped for its axial fixation into the pin hole by positive engagement. On the one hand, the heat treatment of the pin with hardened center is simple and economical and the pin can be obtained from a very economical mass production of rolling elements. On the other hand, such a pin has an end that is not hardened in the pin hole with only positive engagement or with substantially positive engagement, i.e. with full or substantially no interference fit. As can be seen in the case of a caulked pin having a radially expanded distal end as a result of pin rotation, it can be secured without wear.

  Also, the radial spot riveted pin is secured with axial play and / or radial play within the pin hole only by positive engagement. On the one hand, there is no pinning (chucking) force between the pin ends acting in the axial direction on the pin hole and / or on the other hand there is no effect of the interference fitting radial force on the pin hole. This ensures not only high shape stability of the tappet housing, which is relatively thin compared to the extruded parts, but also no special adjustment of pin holes or surface quality due to low manufacturing costs Is possible. Furthermore, the radial play allows automatic rotation of the pin within the pin hole due to a uniform surface load in the area of the drive roller. As a result, the safety from surface wear in the contact area between the pin and the drive roller including any rolling element that can be used is further improved.

  Furthermore, the tappet housing starts from a bead-like recess on the outer peripheral surface of the tappet housing and is directed to the drive roller to lubricate and cool the drive roller and at least one injection extending transversely to the pin It is also advantageous to provide holes.

  Finally, as long as this is possible and appropriate, it can be stated that the above-described embodiments of the present invention can be freely combined with each other or with other known features.

  Further features of the present invention arise from the following description and accompanying drawings that show examples of embodiments of the present invention. Unless indicated otherwise, the first digit of the code corresponds to the corresponding figure and is not listed in the code list. Also, similar or functionally similar components or features are labeled with the same reference only if not otherwise indicated.

1 shows an exploded perspective view of a first example of an embodiment of a tappet of the present invention including an insertion plate. FIG. 1B shows the assembled tappet of FIG. 1A in a perspective cross-sectional view. FIG. 1B shows the tappet of FIG. Fig. 3 shows an exploded perspective view of a second example of an embodiment of a tappet of the present invention including an insertion plate. The assembled tappet of FIG. 2A is shown in a perspective sectional view. 2B is a perspective bottom view of the tappet of FIG. 2B. The tappet of FIG. 2B is shown by a longitudinal cross-sectional view. FIG. 5 shows an exploded perspective view of a third example of an embodiment of a tappet of the present invention including an insertion plate. The assembled tappet of FIG. 3A is shown in a perspective cross-sectional view. Fig. 3B is a perspective bottom view of the tappet of Fig. 3B. FIG. 10 shows an exploded perspective view of a fourth example of an embodiment of a tappet of the present invention including an insertion plate. FIG. 4B shows the assembled tappet of FIG. 4A in a perspective sectional view. A fifth example of an embodiment of a tappet of the present invention including a roller carrier is shown in an exploded perspective view. FIG. 5B shows the assembled tappet of FIG. 5A in a perspective sectional view. The 6th example of embodiment of the tappet of the present invention containing a roller carrier is shown with an exploded perspective view. FIG. 6B shows the assembled tappet of FIG. 6A in a perspective bottom view. FIG. 6B shows a longitudinal sectional view of the tappet of FIG. 6B in an attached state. FIG. 10 shows a longitudinal section view of a seventh embodiment of a tappet of the present invention having altered assembly dimensions. The 8th example of embodiment of the tappet of the present invention provided with a hemispherical contact surface is shown with a longitudinal section. The 9th example of embodiment of the tappet of the present invention containing a roller carrier is shown with an exploded perspective view. The assembled tappet of FIG. 9A is shown in a perspective sectional view. A tenth example of an embodiment of a tappet of the present invention including a roller carrier is shown in an exploded perspective view. FIG. 10A is a perspective cross-sectional view of the assembled tappet of FIG. 10A. It is the schematic of the characteristic movement pattern of the tool for radial spot riveting.

(Detailed description of the drawings)
1A to 1C disclose a mechanical tappet 101 for lift operation of a pump piston (not shown) in a fuel pump of an internal combustion engine. The tappet 101 includes a tappet housing 102 configured as a deep-drawn sheet metal working part having a bush shape and formed of a thin wall. The tappet housing 102 is mounted in a fuel pump tappet guide for longitudinal movement by means of a substantially cylindrical outer peripheral surface 3. In this embodiment, the drive roller 6 attached to the pin 4 via the rolling member 5 configured as a bearing needle functions as a low friction counter surface for a cam (not shown) of the cam shaft of the internal combustion engine. An end 7 of the pin 4 protruding from the drive roller 6 is supported by the pin hole 8 of the tappet housing 102. For the axial fixation of the pins 4 in the pin holes 8 by positive engagement, the ends 7 of the pins 4 can have their tips either caulked or radial spot riveting as described further below. It is enlarged radially by law.

  The tappet 101 further includes a lift transmission element 11. The lift transmission element 11 is configured as an insertion plate 109 and comprises a contact surface 10 for the pump piston on the power take-off (power take-off device) side. The tappet 101 further comprises a washer configured as a snap ring 112. The snap ring 112 forms part of an anti-loss device 114 that extends to the inner peripheral surface 13 of the tappet housing 102. By the loss prevention device 11, the insertion plate 109 is fixed in the tappet housing 102 with a positive engagement. For this purpose, in addition to the snap ring 112, the loss prevention device 114 includes a knob-like protrusion 115 that extends to the inner peripheral surface 13 of the tappet housing 102. The number of protrusions 115 is four in this embodiment, and is formed by stamping the outer peripheral surface 3 of the tappet housing 102. The insertion plate 109 is supported by these protrusions 115 via snap rings 112 that engage under the insertion plate 109.

  In this embodiment, the insertion plate 109, which is made as a fine punching (punching) part, is supported on the axial shoulder 117 in the direction of the drive roller 6 by two arcuate supports 116. The axial shoulder 117 is formed by a flat portion 118 that is recessed in the radial direction from the cylindrical shape on the inner peripheral surface 13 of the tappet housing 102 in the region of the pin hole 8. Further seen on the outer surface of the insert plate 109 are four recesses 19. The recess 19 is required to ensure freedom of movement with respect to the protrusion 115 when the insertion plate 109 is inserted into the tappet housing 102. A protrusion 20 formed integrally with the insertion plate 109 extends through the opening 121 of the tappet housing 102, projects radially beyond the outer peripheral surface 3 of the tappet housing 102, and is a complementary longitudinal groove of the tappet guide. And acts as an anti-rotation body 122 to correctly orient the tappet 101 in the radial direction within the tappet guide, thereby ensuring the orientation of the drive roller 6 parallel to the cam. At the same time, the protrusion 20 is also mounted in the tappet housing 102 so as not to rotate the insertion plate 109.

  Furthermore, the insertion plate 109 also comprises a straight edge 23. The straight edge 23 always provides sufficient ventilation between the insert plate 109 and the inner peripheral surface 13 of the tappet housing 102 for ventilation and oil return or oil circulation during operation of the tappet 101. Configured to do. The straight edge 23 is the same in all other examples of the embodiment of the present invention.

  As a second example of an embodiment of the present invention, FIGS. 2D-2A disclose a tappet identified at 201 with an insertion plate 209. This tappet 201 differs from the tappet 101 described above basically in the shape of the insertion plate 209. The shape of the insertion plate 209 is a box shape in this embodiment, and is supported on the axial shoulder 217 of the tappet housing 202 by the raised rib 24 extending at the support portion 216. The contact that occurs between the rib 24 and the axial shoulder 217, on the other hand, acts as a counter-rotation (anti-rotation) device for the insertion plate 209 in the tappet housing 202. On the other hand, the insertion plate 209 is such that the radial movement of the insertion plate 209 towards the pin 4 due to the angular contact between the rib 24 and the axial shoulder 217 leads to a slight pivoting of the contact surface 10. , With some radial play on the inner peripheral surface 13 of the tappet housing 202. As a result, the contact surface 10 may orient itself on the pump piston so that alignment errors or deviations between the pump piston and the contact surface 10 resulting from part tolerances can be compensated in the contact plane. it can. The contact surface 10 is at least partially in the direction of the connecting line between the ribs 24 in order to ensure contact with the low pressure pump piston without edge loads in the direction transverse to the pivot axis of the insert plate 209. Furthermore, if the lens has a convex cylindrical shape, substantially complete compensation of these alignment errors or deviations is possible.

  Further, the high rigidity of the shape of the insertion plate 209 is compensated by two opposing reinforcing knees 225 disposed between the support portions 216. A further contribution to the rigidity of the shape of the insert plate 209 configured as a perforated bending part in this embodiment is made by the contact surface 10 having a raised shape in the direction of the pump piston.

  The tappet 201 is further different from the tappet 101 in this embodiment by the fact that an anti-rotation body 222 made as a separate component is fixed in the recess 221 of the tappet housing 202. However, a further prominent feature that can optionally be provided in all other examples of the embodiment is also an injection hole 26 for lubricating and cooling the drive roller 6. The injection hole 26 starts from a bead-like recess 27 that communicates with the lubricant supply channel of the tappet guide so that the injection hole 26 extends laterally with respect to the pin 4 and is directed to the drive roller 6. In the example, it is made by stamping the outer peripheral surface 3 of the tappet housing 202 at the center of the flat portion 218.

  The lift transmission element 11 of the tappet 301 shown in FIGS. 3A to 3C is similarly configured as an insertion plate 309. In contrast to the insert plate 209, the insert plate 309 has a tab-shaped shape and includes a flat frame portion 28 surrounding an inner portion 29 having a U-shaped cross section. The inner part 29 is also provided with a contact surface 10 which also rises in the direction of the pump piston. The flat portion 318 of the tappet housing 302 is recessed in the radial direction from the cylindrical shape. As a result, a substantially sickle-shaped gap 30 is formed in each flat portion 318 of the tappet housing 302. This forming is suitably effected by local cutting of the tappet housing 302 during the sheet metal forming procedure. As a result, the axial shoulder 317 is formed adjacent to the gap 30 in the form of a straight edge end face 331 in this embodiment. The insertion plate 309 is supported on these end surfaces 331 by the opposing support portions 316 of the frame portion 28 in the direction of the drive roller 6. In order to ensure support without edge loads on the end surface 331 of the insert plate 309 in consideration of bending due to the load of the insert plate 309, these end surfaces 331 have a slightly convex surface in the radially inner direction. Has been.

  A further salient feature of tappet 301 relates to a loss prevention (anti-loss) device 314 for insertion plate 309. The loss prevention device 314 includes a protrusion 315 made by local caulking on the inner peripheral surface 13 of the tappet housing 302 having a stepped inner diameter, and a corresponding number of recesses 32 on the outer surface of the insertion plate 309. The protrusion 315 reliably engages the recess 32 in both the axial direction and the radial direction. The caulking procedure for making the protrusion 315 is suitably performed during the soft phase of the tappet housing 302. As a result, the manufacturing and assembly sequence of tappet 301 for this type of loss prevention device 314 must change the manufacturing and assembly sequence used for tappets 101 and 201 throughout. The insert plate 309 must be attached to the tappet housing 302 prior to heat treatment and must be polished with the tappet housing 302 after curing.

  The tappet 401 shown in FIGS. 4A and 4B differs from the above-described tappet 301 due to the fact that the insertion plate 409 of this embodiment has a continuous tab shape. As a result, the opposing support 416 has a U-shaped cross section and is supported by an axial shoulder 417 of a substantially complementary arcuate edge of the tappet housing 402 formed as an arcuate end surface 431. Good contact of the support 416 with the end surface 431 is achieved by making the end surface 431 with a slightly larger curvature than the support 416. Instead of the arc-shaped contact members 416 and 431, it is also possible to make a U-shaped cross section of the support portion 416 having a so-called gothic shape having arcs with two center points shifted. In order to guarantee the support without the edge load on the end surface 431 of the insertion plate 409 in consideration of the bending due to the load of the insertion plate 409, the end surface 431 is slightly surfaced in the radially inner direction also in this embodiment. It is convex. The fact that this type of support of the insert plate 409, corresponding to a rotating knuckle joint, also causes an alignment error or deviation between the pump piston and the contact surface 10 due to component tolerances, and the fact that the insert plate 409 rotates slightly on the end face 431. Can compensate in the plane of rotation. As explained above, substantially complete compensation of these alignment errors and deviations can also be achieved in this embodiment by forming the contact surface 10 having a convex cylindrical shape. This is because, in this embodiment, the plane of rotation of the insertion plate 409 extends laterally with respect to the pin 4, but the columnar shape of the contact surface 10 is oriented perpendicular to the virtual connection line between the support portions 416. This is because that.

  A further tappet 501 of the present invention is disclosed in FIGS. 5A and 5B. Instead of the lift transmission element 11 configured as an insertion plate, in this embodiment, a roller carrier 533 that forms a U-shape in the direction of the pin 4 is used. The roller carrier 533 includes a flat bottom portion 434 having a contact surface 10 and side portions 535 bent at an angle from the bottom portion 534 toward the pin 4. The roller carrier 533 is a pin that extends into the side 535 through the pin hole 36 so that the end 7 of the pin 4 is supported by both the pin hole 8 of the tappet housing 502 and the pin hole 36 of the side 535. 4 is movable joined.

  The pin hole 8 in the tappet housing 502 and / or the pin hole 36 in the side 535 is relative to the pin 4 such that the roller carrier 533 is inserted into the tappet housing 502 to pivot about or together with the pin 4. To the required size. With this device, the cam force acting on the drive roller 6 is transmitted via the pin 4 to the roller carrier 533 and its contact surface 10 on the pump piston, and to the tappet housing 502 via the pin 4. And transverse component forces conducted from the tappet housing 502 to the tappet guide. Thus, considering only the transversal force transmitted, it is possible to form a tappet housing 502 which has a particularly thin wall and thereby has a particularly light weight. The rigidity due to the shape of the roller carrier 533 required to transmit the force of the longitudinal component is made as a perforated bending part made of sheet metal, and in the case of this roller carrier 533 having only a smaller mass, the roller carrier 533 This can be accomplished by providing a reinforced knee 525 starting from the flat bottom 534 and extending transversely to the side 535.

  A further example of an embodiment of a tappet 601 of the present invention is disclosed in FIGS. 6A-6B. In this example, the roller carrier 633 comprises a tab-shaped bottom 634 having a U-shaped cross section extending transversely to the direction of the pins 4. The shape rigidity of the roller carrier 633 thus obtained is further reinforced by the reinforcing knee-shaped portion 625 and the rib 37. The ribs 37 extend on both sides of the contact surface 10 formed on the bottom 634 in a shape protruding in the direction of the pump piston in parallel with the U shape. As already described above, the tappets 501 and 601 are further in the shape of their tappet housings 502 and 602, with the flat portion 618 of the tappet housing 602 retracting radially from the cylindrical shape thereby forming the sickle-shaped gap 30. However, they are different from each other in that the flat portion 518 of the tappet housing 502 is formed with a transition portion closed to a cylindrical shape.

  The tappet guide and pump piston already described at the beginning can be seen in the longitudinal section of the tappet 601 in FIG. 6C, which are identified at 38 and 39 respectively in FIG. 6C. 7 and 8 showing the tappets 701 and 801 at the same time, it becomes clear that the tappet with the roller carrier has a high flexibility with respect to the modular design as described below. If the tappet guide 38 permits the use of the same tappet housings 602 and 702, different assembly dimensions 40 or different rollers with different assembly dimensions 41 may result in a distance between the drive roller 6 and the contact surface 10. It is sufficient to use carriers 633 and 733. Conversely, for example, in the case of tappet guides 38 that are different in diameter but have the same assembly dimension 40, the modular design allows the same roller carriers 633 and 733 to be used in different tappet housings 602 and 702. To do.

  Another possibility arising from the modular design is disclosed in the tappet 801 shown in FIG. The tappet 801 includes a roller carrier 833, and the contact surface 10 of the roller carrier 833 is configured as a hemispherical cavity 42 of the bottom 834. Such a cavity 42 is suitable, for example, for receiving a pump piston ending in a spherical shape or for receiving the spherical end of a gas exchange valve push rod.

  A further example of an embodiment of the present invention is disclosed in FIGS. 9A and 9B showing a tappet 901. The tappet 901 includes a tappet housing 902 having a window 43, and the window 43 is located at a transition portion 44 between the cylindrical shape and the flat portion 918. The side portion 935 extends through the window 43 so that the side portion 935 of the roller carrier 933 can engage the outside of the flat portion 918. An important advantage of this arrangement over the example of the embodiment described above is that it creates a larger design space with respect to the width of the drive roller 6. The basic load rating (load rating) or durability of the drive roller 6 increases with the width. Further effects, particularly over the tappet housings 202-602, are also seen in the relatively large surface flats 918, which provide sufficient wear resistance as an axial running surface for the drive roller 6. Should have.

  A further tappet 1001 of the present invention comprising a roller carrier 1033 is disclosed in FIGS. 10A and 10B. The tappet 1001 includes a tappet housing 1002 having a double wall structure in the region of the pin hole 8. For this purpose, the pin hole 8 is arranged in a tongue 45 formed integrally with the tappet housing 1002. After being bent inwardly, these tongues 45 extend parallel to the outer peripheral surface 3 of the tappet housing 1002. The side 1035 of the roller carrier 1033 engages the tongue 45 on the outside, and therefore extends between the inner peripheral surface 13 of the tappet housing 1002 and the tongue 45. Alternatively, it is possible to provide a tongue that is very closely spaced from the inner peripheral surface 13 of the tappet housing 1002. As a result, in this case, the changed side of the roller carrier extends inside the tongue. An opening 46 extending to the same height as the pin hole 8 penetrating the outer peripheral surface 3 of the tappet housing 1002 is used to insert the pin 4 and to hold the rolling member 5 in the drive roller 6 not yet mounted. It merely serves as a mounting opening for extruding (not shown) and also serves as an access for the forming tool. In order to fix the pins 4 in the axial direction by positive engagement in the pin holes 8 using this molding tool, the ends 7 of the mounted pins 4 are radial in their tips (front end). To be spread. This is the same for all embodiments described herein by both the known coking method and the radial spot riveting method known per se and briefly described below. It can be carried out.

  The pin 4 made of rolled bearing steel such as 100Cr6 is hardened in the center over its entire length and has a Rockwell hardness HRC of at least 58, corresponding to a Vickers hardness HV of at least 650. Despite complete center hardening and the accompanying brittleness of the pin 4, the end 7 of the pin 4 is typical in this riveting method with radial spot riveting and substantially without material delamination or cracking. The lens shape has a convex spherical contour. This lens shape is clearly shown in the longitudinal sectional views of tappets 701 and 801.

  Referring to FIG. 11, this lens shape results from a spatial pattern of movement of a riveting die (die) 47 (made from hard metal in this embodiment) of a radial spot riveting machine. Is clear. In this pattern of movement, the longitudinal axis 48 of the riveting mold 47 follows a periodic loop (circulation) line 49 and the envelope of the loop line 49 tapers towards the workpiece, ie towards the pin 4. A cone is formed. During this movement, the longitudinal axis 48 of the riveting mold 47 crosses the central axis 50 of the repeating cone. Due to the high load contact between the flat tip of the riveting mold 47 and the end 7 of the pin 4, these ends 7 are continuously deformed in the radial direction at their tips.

  Tests performed by the applicant confirmed the basic suitability of this type of pin fixation in a tappet corresponding to the tappet 601 shown in FIGS. 6A and 6B. A pin 4 having a diameter of approximately 7.6 mm was made from type 100Cr6 rolled bearing steel and the center was hardened to a hardness of about 60 HRC. The deformation of the tip of the mounted pin 4 is about 25 KN riveting force and about 2 seconds at each of the two ends 7 with a hydraulic spot riveting machine having a flat riveting mold 12 (FIG. 11). Of riveting time. Subsequent measurements of the pin 4 thus deformed showed that the end 7 was widened by about 0.1 mm with respect to the diameter. The play for adjusting the pin 4 in the pin hole 8 is fixed to the pin hole 8 with radial play and slight play in the radial direction after radial spot riveting. Sized as needed. It was possible to completely eliminate the deformation of the thin-walled tappet housing 602 caused by axial or radial connection stress acting on the pin holes and impairing the required cylindrical shape of the tappet housing 602. On top of that, the axial force required to push the pin out of the pin hole 8 in spite of the relatively small opening 7 of the pin 4 has an average value of 2700 N and the pin with the tip coked The level of the reference component with

DESCRIPTION OF SYMBOLS 1 Tappet 2 Tappet housing 3 Outer peripheral surface of tappet housing 4 Pin 5 Rolling member 6 Drive roller 7 Pin end 8 Pin hole 9 Insertion plate 10 Contact surface 11 Lift (stroke) transmission element 12 Snap ring 13 Inner periphery of tappet housing Surface 14 Anti-loss device 15 Protrusion 16 on the inner peripheral surface of the tappet housing 17 Insert plate support 17 Axial shoulder 18 Tappet housing flat 19 Insert plate recess 20 Insert plate protrusion 21 Tappet housing opening 22 Anti-rotation body 23 Insert plate edge 24 Support element rib 25 Reinforcement knee-shaped portion 26 Injection hole 27 Bead-like recess 28 Insert plate frame (frame) portion 29 Insert plate inner portion 30 Sickle-shaped gap 31 End surface 32 Insert plate Recess 33 of roller carrier 34 Roller carrier bottom 35 Roller carrier side 36 Side pin hole 37 Roller carrier rib 38 Tappet guide 39 Pump piston 40 Tappet assembly dimensions 41 Different assembly dimensions 42 Hemispherical cavity 43 Tappet housing window
44 Tappet housing transition 45 Tappet housing tongue 46 Tappet housing opening 47 Riveting mold 48 Riveting mold longitudinal axis 49 Loop line 50 Central axis

Claims (22)

In particular, mechanical tappets (101, 201, 301, 401, 501, 601, 701, 801, 901, 1001) for lift operation of a pump piston (39) in a fuel pump of an internal combustion engine, the tappet being a sheet metal Bush-shaped tappet housing (102, 202, 302, 402, 502) configured as a work piece and installed by a substantially cylindrical outer peripheral surface (3) in the tappet guide (38) for longitudinal movement , 602, 702, 902, 1002), and the tappet further includes a drive roller (6) rotatably mounted, and a lift transmission element (11), wherein the lift transmission element (11) Tappet housing (102, 202, 302, 402, 502, 602, 702, 902, 1002) Separately made and inserted into the tappet housing and having a contact surface (10) for the pump piston (39) on the power take-off side, the drive roller (6) is optionally a rolling element (5) The end (7) of the pin (4) that is attached to the center of the pin (4) and protrudes from the drive roller (6) is connected to the tappet housing (102, 202, 302, 402, 502, 602, 702, 902, 1002) are supported in the pin holes (8) ,
The flat portion (118, 218, 318, 518) in which the tappet housing (102, 202, 302, 402, 502, 602, 702, 902) is recessed radially from the cylindrical shape in the region of the pin hole (8). 618, 918),
The lift transmitting element (11) is configured as an insert plate (109, 209, 309, 409), the insert plate being in the direction of the drive roller (6) the tappet housing (102, 202, 302, 402) The axial shoulders (117, 217, 317, 417) are supported on the tappet housing (118, 218, 318) by the flat portions (118, 218, 318). 102, 202, 302, 402) formed on the inner peripheral surface (13) . The lift transmission element (11) is made as one of the stamped parts or stamped and bent part, the tappet according to claim 1. In the region of the pin hole (8), the tappet housing (1002) is a double wall, the pin hole (8) extends parallel to the outer peripheral surface (3) of the tappet housing (1002) and the tongue of the tappet housing bent into the tappet housing (1002) within the (1002) is arranged to (45), the tappet according to claim 1. The tappet housing (102, 202, 302, 402, 502, 602, 902, 1002) includes a recess (121, 221), and the tappet housing (102, 202, 302, 402, 502, 602, Anti-rotation bodies (122, 222) projecting radially beyond the outer peripheral surface (3) of 902, 1002) are used for the correct orientation of the drive roller (6) in the tappet guide (38). that, tappet according to claim 1. It said flat portion (318,618) forms a substantially sickle gap (30) in the tappet housing (302,602), the tappet according to claim 1. Said anti-rotation member (122) is constituted by said insert plate (109) to the projection projecting through a recess (121) of and the tappet housing is integrally formed (102) (20), according to claim 4 Tappet described in. Said insert plate (109) has a planar shape, is supported in the axial direction shoulder (117) by the support portions of the two arcuate shape positioned opposite each other (116), the tappet according to claim 1 . The insertion plate (209) has a box shape and is supported on the axial shoulder (217) by raised ribs (24) extending on two support portions (216) located on opposite sides, insert plate (209) further comprises two opposing reinforcing geniculate portion extending (225) between the support (216), the tappet according to claim 1. The insertion plate (309) has a tab-shaped shape with a flat frame-like part (28) surrounding an inner part (29) having a U-shaped cross section, the frame-like part (28) being two opposite. by the support unit (316) is supported in the composed direction shoulder (317) as the gap (30) and extending parallel to and end face of the straight edge (331), the tappet of claim 5. The insertion plate (409) has a U-shape and is supported on the axial shoulder (417) by two opposing support portions (416) having a U-shaped cross section, and the axial shoulder (417). but the composed U-shaped cross-section substantially complementary to a and the gap (30) and arcuate end surface extending parallel to (431), the tappet of claim 5. With the aid of a loss prevention device (114, 314), the insertion plate (109, 209, 309, 409) extends to the inner peripheral surface (13) of the tappet housing (102, 202, 302, 402). is inserted in a secure engagement within the housing (102, 202, 302, and 402), the tappet according to claim 1. The loss prevention device (114) is made by stamping the snap ring (112) for supporting the insertion plate (109, 209) and preferably the inner peripheral surface (13) of the tappet housing (102, 202). is provided with a knob-like projections (115) for supporting the snap ring (112), the tappet according to claim 11. The loss prevention device (314) preferably has projections (315) made by coking of the inner peripheral surface (13) of the tappet housing (302, 402) and the insertion for receiving these projections (315) comprising a plate (309,409) to the created recesses (32), the tappet according to claim 11. In particular, mechanical tappets (101, 201, 301, 401, 501, 601, 701, 801, 901, 1001) for lift operation of a pump piston (39) in a fuel pump of an internal combustion engine, the tappet being a sheet metal Bush-shaped tappet housing (102, 202, 302, 402, 502) configured as a work piece and installed by a substantially cylindrical outer peripheral surface (3) in the tappet guide (38) for longitudinal movement , 602, 702, 902, 1002), and the tappet further includes a drive roller (6) rotatably mounted, and a lift transmission element (11), wherein the lift transmission element (11) Tappet housing (102, 202, 302, 402, 502, 602, 702, 902, 1002) Separately made and inserted into the tappet housing and having a contact surface (10) for the pump piston (39) on the power take-off side, the drive roller (6) is optionally a rolling element (5) The end (7) of the pin (4) that is attached to the center of the pin (4) and protrudes from the drive roller (6) is connected to the tappet housing (102, 202, 302, 402, 502, 602, 702, 902, 1002) are supported in the pin holes (8),
The lift transmission element (11) is configured as a roller carrier (533, 633, 733, 833, 933, 1033) supported by the pin (4), and the roller carrier (533, 633, 733, 833, 933). 1033) has a bottom (534, 634, 834) having a contact surface (10), and a side (535, 935,) that forms an angle from the bottom (534, 634, 834) to the pin (4). 1035), forming a U-shaped cross section in the direction of the pin (4), and the end (7) of the pin (4) is connected to the tappet housing (502, 602, 702, 902, 1002). ) and pin hole (8) of, and is supported on both the pin hole (36) of the side (535,935,1035), the tappet. The roller carrier (533, 633, 733, 833, 933, 1033) is rotated by the tappet housing (502, 602, 702, 902, 1002) around the pin (4) or for pivoting with the pin (4). ) Are inserted into the tappet housing (502, 602, 702, 902, 1002) and / or the pin holes (36) of the side portions (535, 935, 1035). 15. Tappet according to claim 14 , sized as required for the pin (4). The bottom (534) has a substantially flat shape and the roller carrier (533, 933, 1033) extends laterally from the bottom (534) to the side (535, 935, 1035). comprising a reinforcing geniculate portion (525) which, tappet according to claim 14. The bottom (634,834) are made on the tab-shaped having a U-shaped cross section which extends transversely to the direction of the pin (4), the tappet according to claim 14. The tappet housing (502, 602, 702, 902) has a flat portion (518, 618, 918) that is recessed radially from a cylindrical shape in the region of the pin hole (8);
The side (935) extends through the window (43) of the tappet housing (902) and engages with the outside of the flat portion (918) behind, each window (43) having the cylindrical shape the transition between the one of the flat portion (918) made in the (44), the tappet according to claim 14. Said contact surface (10), tappet according constituted, in claim 14 as a hemisphere cavity (42) of said bottom (834). The pin (4) is axially fixed by positive engagement with the pin hole (8) by a radially extending end (7), the pin (4) having a central hardness of at least 58 HRC over its entire length the cured central portion, said end portion (7), is widened by radial spot riveting, tappet according to claim 1. It said pin (4) with play in the axial play and / or radially fixed to the pin hole (8), the tappet according to claim 20. The tappet housing (202, 502) includes at least one injection hole (26), and the injection hole (26) is a bead-like recess (27) on the outer peripheral surface (3) of the tappet housing (202, 502). starting from), the conjunction is directed to the drive roller (6), extends transversely to the pin (4), the tappet according to claim 1.

Images