SHIFT GATE, SLIDING CAM SYSTEM AND CAMSHAFT

Abstract

A shift gate for a sliding cam system may include at least two shift grooves for engagement of at least one actuator pin. The two shift grooves run against a direction of rotation and transform from a first inlet portion for the actuator pin into a second outlet portion for the actuator pin. The two shift grooves cross one another in an intersection region between the two portions. In the intersection region, the two shift grooves each have a maximum axial shift stroke that is greater than half a total axial shift stroke, in particular a slide travel, of the shift gate.

Claims

1-13. (canceled)

14. A shift gate for a sliding cam system, comprising: shift grooves for engagement of an actuator pin, wherein the shift grooves run against a direction of rotation and transform from a first inlet portion for the actuator pin into a second outlet portion for the actuator pin, wherein the shift grooves cross one another in an intersection region between the first inlet portion and the second outlet portion, wherein in the intersection region each shift groove has a maximum axial shift stroke that is greater than half a total axial shift stroke of slide travel of the shift gate.

15. The shift gate of claim 14 wherein the maximum axial shift stroke of the shift grooves is less than the total axial shift stroke of the shift gate.

16. The shift gate of claim 14 wherein each of the shift grooves has an inlet flank in the first inlet portion and an outlet flank in the second outlet portion, wherein the inlet and outlet flanks are parallel to one another and are spaced apart by an axial distance that corresponds to at least half the total axial shift stroke of the shift gate.

17. The shift gate of claim 16 wherein in the second outlet portion, starting from the intersection region, each of the shift grooves comprises a braking flank for braking the actuator pin, which forms a continuous transition to the outlet flank.

18. The shift gate of claim 17 wherein the braking flank is arcuate at least in portions.

19. The shift gate of claim 14 wherein the shift grooves are spaced apart in the first inlet portion and partially axially overlapping in the second outlet portion so that the shift grooves form a common groove.

20. The shift gate of claim 19 wherein the common groove includes a groove width that is greater than a groove width of the respective shift groove in the first inlet portion.

21. The shift gate of claim 14 comprising a guide web disposed between the shift grooves, wherein in the first inlet portion the guide web extends at least partially along the shift grooves and tapers towards the intersection region.

22. A sliding cam system comprising: a. double pin actuator; and a sliding cam element that includes a shift gate and is lockable in at least two axial positions, wherein the shift gate includes shift grooves, wherein during a. sliding process a respective one of the shift grooves cooperates with an actuator pin of the double pin actuator, wherein the shift grooves run against a. rotation direction and transform from a first portion into a. second portion, wherein the shift grooves cross one another between the first and second portions, wherein each of the shift grooves has a maximum axial shift stroke that is greater than half a total axial shift stroke of the shift gate.

23. The sliding cam system of claim 22 wherein the total axial shift stroke of the shift gate is substantially equal to a distance between the at least two axial positions of the sliding cam element.

24. The sliding cam system of claim 22 comprising a latching device configured such that during a sliding process, after reaching the maximum axial shift stroke of the respective shift groove, the latching device pulls the sliding cam element in a. slide direction to the corresponding axial position.

25. The sliding cam system of claim 22 wherein the actuator pin is a first actuator pin of at least two actuator pins of the double pin actuator, wherein the at least two actuator pins are spaced apart by a distance that corresponds to at least half of the total axial shift stroke of the shift gate.

26. A camshaft that includes the shift gate of claim 14.

Description

[0029] The invention is explained in more detail below with further features with reference to the appended drawings. The embodiment illustrated constitutes examples of how the shift gate according to the invention may be configured.

[0030] In the drawings:

[0031] FIG. 1 shows a schematic illustration of the implementation of a shift gate with an X shift groove according to the prior art;

[0032] FIG. 2 shows a schematic illustration of the implementation of a shift gate with a Y shift groove according to the prior art; and

[0033] FIG. 3 shows a schematic illustration of the implementation of a shift gate according to a preferred exemplary embodiment of the invention.

[0034] FIG. 1 shows schematically an implementation of a circumferential portion of a shift gate 10 according to the prior art, wherein the shift gate 10 has two shift grooves 11 which are together formed as an X groove. The shift gate 10 comprises a first portion 12, a second portion 13 and an intersection region 14 arranged in between in the circumferential direction. The two shift grooves 11 run from the first portion 12 through the intersection region 14 into the second portion 13 and cross one another in the intersection region 14.

[0035] As FIG. 1 shows, the two shift grooves 11 have a same axial distance from one another in the two portions 12, 13. The two shift grooves 11 thus have a maximum axial shift stroke SH in the intersection region 14 which corresponds to half the total shift stroke GSH of the shift gate 10. FIG. 1 furthermore shows an actuator pin 20 which engages in one of the two shift grooves 11 and cooperates therewith for axial sliding of the shift gate 10.

[0036] The maximum axial shift stroke SH described above according to FIG. 1 has the disadvantage that if the shift speeds are too low, e.g. due to low rotation speeds of a camshaft (not shown) to which the shift gate 10 is coupled, after the actuator pin 20 has passed the intersection region 14, there is a risk of autonomous return movement or jump-back of the shift gate 10 into the first axial position, in particular the starting position.

[0037] FIG. 2 shows a schematic implementation of a circumferential portion of a further shift gate 10 according to the prior art, wherein the shift gate 10 has two shift grooves 11 which jointly form a Y groove. In contrast to the shift gate 10 from FIG. 1, the two shift grooves 11 run from the first portion 12 into the second portion 13 without crossing. The shift grooves 11 in the second portion 13 form a common groove 18 which substantially has a groove width which corresponds to the two identical groove widths of the two shift grooves 11 in the first portion 12. Furthermore, the two shift grooves 11 have an axial distance from one another only in the first portion 12. In the second portion 13, the two shift grooves 11 are formed completely congruent with one another.

[0038] As FIG. 2 shows, the two shift grooves 11 have a maximum axial shift stroke SH in the opening region 21 which corresponds to the total shift stroke GSH of the shift gate 10. In other words, the maximum axial shift stroke SH of the respective shift grooves 11 corresponds to the full axial stroke or full slide travel of the shift gate 10. In comparison with the shift gate 10 with X groove arrangement according to FIG. 1, the shift gate 10 with Y groove arrangement has a greater axial extent of the circumferential region in which the two shift grooves 11 extend in the circumferential direction. The shift gate 10 according to FIG. 2 thus requires more installation space.

[0039] According to FIG. 2, furthermore at least two actuator pins 20 are required for axial sliding of the shift gate 10. The axial distance X′ between the two pins 20 corresponds to the total axial shift stroke GSH of the shift gate 10. The shift gate 10 shown in FIG. 2 has the further disadvantage that it has a hard transition in the opening region 21 in which the two shift grooves 11 open into one another, so that during a sliding process, in the opening region 21, high axial forces act on the engaged actuator pin 20.

[0040] FIG. 3 shows an implementation of a circumferential region of the shift gate 10 according to a preferred exemplary embodiment of the invention. The circumferential region shown, like the circumferential regions shown in FIGS. 1 and 2, corresponds to a schematic illustration. The shift gate 10 serves for axial sliding of a sliding cam element (not shown) on a camshaft. The shift gate 10 may also be used to slide other elements arranged on a shaft in the longitudinal direction.

[0041] The shift gate 10 comprises a first portion 12, a second portion 13 and an intersection region 14 arranged in between in the circumferential direction. The first portion 12 corresponds to an inlet portion in which an actuator pin 20 enters the associated shift groove 11 in order to cooperate therewith for an axial sliding of the shift gate 10 or of a sliding cam element (not shown) coupled to the shift gate 10. The second actuator portion 13 corresponds to an outlet portion in which the actuator pin 20 is situated after the sliding process and from which the actuator pin 20 preferably exits the groove.

[0042] The shift gate 10 furthermore has two shift grooves 11 which run against the rotation direction of the shift gate 10 from the first portion 12 into the second portion 13, and cross one another in the intersection region 14. The two shift grooves 11 cross at a crossing point KP in the intersection region 14. In other words, the shift grooves 11 change axial sides relative to the first portion 12. It should be mentioned that the intersection region 14 does not form a clearly separated intermediate region, but is formed by respectively a part of the first portion 12 and a part of the second portion 13. The crossing point KP forms the center of the intersection region 14.

[0043] As FIG. 3 shows, in the first portion 12 the two shift grooves 11 have a first axial distance from one another, and in the second portion 13 a second axial distance which is less than the first axial distance. The axial distances are measured between the mutually parallel shift groove regions 22 of the two shift grooves 11 in the respective portion 12, 13.

[0044] In the intersection region 14, the two shift grooves 11 each have a maximum axial shift stroke SH which is greater than half a total axial shift stroke GSH of the shift gate 10. In addition, the maximum axial shift stroke SH of the shift grooves 11 is smaller than the total axial shift stroke GSH. To summarize, the maximum axial shift stroke SH is thus greater than half the total shift stroke GSH and smaller than the entire total shift stroke GSH of the shift gate 10.

[0045] The total axial shift stroke GSH of the shift gate 10 corresponds to the maximum slide travel of the shift gate 10 in the longitudinal direction of e.g. a shaft (not shown), in particular a camshaft, which the shift gate 10 covers during a sliding process between at least two axial positions, in particular axial end positions, e.g. on a shaft, in particular a camshaft. In other words, during a sliding process, the shift gate 10 is moved from a first axial position to a second axial position, wherein the axial slide travel covered corresponds to the total axial shift stroke GSH of the shift gate 10.

[0046] As evident from FIG. 3, the two shift grooves 11 are formed separately from one another in the first portion 12. In concrete terms, in the first portion 12, a guide web 19 is axially arranged between the shift grooves 11 and partially separates the two shift grooves 11 from one another in the circumferential direction. The guide web 19 extends partially along the shift grooves 11 and tapers towards the intersection region 14. The shift grooves 11 may have a constant groove width or a varying, in particular changing groove width along the guide web 19. The groove widths of the two shift grooves 11 are the same size in the first portion 12.

[0047] In the second portion 13, the two shift grooves 11 partially overlap one another axially so that the two shift grooves 11 form a common groove 18. In other words, the two separate shift grooves 11 transform into one another against the rotation direction, wherein the two shift grooves 11 form a common groove 18 from the crossing point KP. In the second portion 13, there is no web between the two shift grooves 11.

[0048] The common groove 18 has a groove width which is greater than the groove width of the respective shift groove 11 in the first portion. The groove width of the common groove 18 may correspond to twice the groove width of the respective shift groove 11 in the first portion 12. The groove width of the common groove 18 may also be less than or equal to twice the width of the respective shift groove 11 in the first portion 12.

[0049] According to FIG. 3, the two shift grooves 11 each have an inlet flank 15 in the first portion 12 and an outlet flank 16 in the second portion 13, the flanks running parallel to one another and at an axial distance X from one another which corresponds to at least half the total axial shift stroke GSH of the shift gate 10. The axial distance X is formed between the respective inlet flank 15 of the two shift grooves 11 and the respective outlet flank 16 of the respective axially opposite shift groove 11.

[0050] Furthermore, in the first portion 12, the shift grooves 11 each have an acceleration flank 23 for an actuator pin 20, which extends from the inlet flank 15 towards the intersection region 14. The acceleration flank 23 here has axial offset which corresponds to the maximum axial shift stroke SH. Furthermore, in the second portion 13, starting from the intersection region 14, the shift grooves 11 each have a braking flank 17 for braking the actuator pin 20, which forms a continuous transition towards the outlet flank 16. The respective braking flank 17 is configured so as to be accurate. The acceleration flank 23 is structurally separated from the braking flank 17 in the intersection region 14. In the intersection region 14, the acceleration flank 23 of the respective shift groove 11 structurally transforms into the braking flank 17 of the respective other shift groove 11.

[0051] A sliding process of the shift gate 10 is described below in which the shift gate 10 is moved from a first axial position to a second axial position. An actuator pin 20 of a multiple actuator (not shown) cooperates with one of the shift grooves 11. During the sliding process, the shift gate 10 rotates and the actuator pin 20 is arranged in a fixed location in the circumferential direction. It performs only an insertion and retraction movement relative to the shift groove 11.

[0052] In a first step, the actuator pin 20 enters the shift groove 11 in the first portion 12 and is force-guided in the circumferential direction between the guide web 19 and the inlet flank 15. The shift groove 11 is designed so as to be sufficiently wide for a clearance to form between the guide web 19 and the inlet flank 15 or acceleration flank 23.

[0053] As the shift gate 10 rotates further, the inlet flank 15 transforms into the acceleration flank 23. The actuator pin 20 slides along the acceleration flank 23, wherein the shift gate 10 slides in the sliding direction. When the actuator pin 20 is in the intersection region 14 of the two shift grooves 11, at the maximum axial shift stroke SH of the shift groove 11, the shift gate 10 has moved over half the total axial shift stroke GSH of the shift gate 10. In this position, the shift gate 10 is closer to the second axial position than the first axial position, so that the shift gate 10 is pulled, e.g. by a latching device, to the second axial position. In the intersection region 14, the actuator pin 20 changes from the acceleration flank 23 to the braking flank 17 of the shift groove 11, and slides along this in the second portion 12. Then the actuator pin 20 transfers from the braking flank 17 to the outlet flank 16, wherein the shift gate 10 is here situated at the second axial position, in particular the axial end position.

[0054] For axial sliding of the shift gate 10, two actuator pins 20 are provided, wherein a respective one of the actuator pins 20 cooperates with the shift gate 10 to slide in one of the two sliding directions. The two actuator pins 20 have an axial distance X′ from one another which corresponds to the axial distance X between the inlet flank 15 of the respective one shift groove 11 and the outlet flank 16 of the respective other shift groove 11.

LIST OF REFERENCE SIGNS

[0055] 10 Shift gate

[0056] 11 Shift grooves

[0057] 12 First portion

[0058] 13 Second portion

[0059] 14 Intersection region

[0060] 15 Inlet flank

[0061] 16 Outlet flank

[0062] 17 Braking flank

[0063] 18 Common groove

[0064] 19 Guide web

[0065] 20 Actuator pin

[0066] 21 Opening region

[0067] 22 Parallel shift groove regions

[0068] 23 Acceleration flank

[0069] SH Maximum axial shift stroke of shift grooves

[0070] GSH Total axial shift stroke of shift gate

[0071] KP Crossing point

[0072] X Axial distance between inlet and outlet flanks

[0073] X′ Axial distance between actuator pins