shift actuator

Abstract

The present invention relates to a shift actuator for driving a linear lever (30), comprising: a rotating member rotatable but immovable in an axial direction defined by its axis of rotation; a motor (8) for rotating the rotating member, the linear lever (30) being driven by the rotational motion of the rotating member, the rotational motion being driven by two cylindrical cams (1, 2) having identical design and supported for axial movement, and disposed between two opposing end stops (5, 6) oriented opposite to each other and rotate-aligned relative to each other and coaxial with the axis of rotation; and a spring mechanism (7) disposed between two opposing end stops (5, 6). Two cylindrical cams (1, 2) are biased apart, each cylindrical cam (1, 2) having an external cam surface configuration configured to engage with one of the two cam followers, such that the two cylindrical cams (1, 2) and the spring mechanism (7) between them engage with a linear rod (30) – such that when the rotating member rotates first in a first direction of rotation and then in a second direction opposite to the first direction, the linear rod (30) is driven from the neutral position to the engaged position and back to the neutral position in the first direction, and when the rotating member is driven first to rotate in the second direction and then in the first direction of rotation, the linear rod (30) is engaged. 0) Move from the neutral position to another engaged position and back to the neutral position in a second direction opposite to the first direction, and - such that when the linear rod (30) is driven from the engaged position to the neutral position, it is driven in a rigid mode, wherein the movements of the cylindrical cam and the linear rod are linked, and when the linear rod (30) is driven from the neutral position to the engaged position, it is driven in a flexible mode, wherein the movements of the cylindrical cam and the linear rod are disengaged, such that in the case of the linear rod jamming, one of the two cylindrical cams (1, 2) is driven axially away from its end stop (5, 6), thereby compressing the spring mechanism when the linear rod (30) jams. (7) To store driving force, characterized in that the rotating member is connected to the shaft (4) of the two cylindrical cams in an anti-torque engagement manner, but allows them to move axially along the shaft (4); the linear rod (30) is supported radially outward relative to the two cylindrical cams (1, 2) and is provided with two inwardly projecting cam followers (31, 32); the shift actuator is adapted to shift the linear rod (30) in a sequence of shift states, wherein the states of first gear engagement, first neutral, second gear engagement, second neutral and third gear engagement follow each other, wherein shifting in the sequence is achieved by the cam surface configuration of the two cylindrical cams (1, 2).

Description

[0001] This invention relates to a shift actuator for driving a linear lever to actuate a shift fork, comprising: a rotating member supported for rotation but not for movement in an axial direction defined by its axis of rotation; an electric motor for rotating the rotating member, wherein the linear lever is driven by the rotational motion of the rotating member for linear movement parallel to the axial direction, the linear movement being driven by two cylindrical cams having identical design and supported for movement in the axial direction, and arranged in opposite orientations, rotatably aligned relative to each other, and coaxially disposed between two opposing end stops, the two end stops being positioned at a fixed axial distance from each other; and a spring mechanism disposed between the two cylindrical cams to bias them apart, each toward a corresponding one of the two end stops, wherein each of the two cylindrical cams has an outer cam surface configuration configured to cooperate with one of the two cam followers, such that the two cylindrical cams and the spring mechanism therebetween cooperate. Such that when the rotating member is driven to rotate first in a first rotational direction and then in a second rotational direction opposite to the first rotational direction, the linear rod is driven axially in the first direction from the neutral position to the engaged position and back to the neutral position; and when the rotating member is driven first in the second rotational direction and then in the first rotational direction, the linear rod moves in the second direction opposite to the first direction from the neutral position to another engaged position and back to the neutral position. This allows the linear lever to be driven in a rigid mode when it is driven from the engaged position to the neutral position, where the movements of the cylindrical cam and the linear lever are coupled. Conversely, when the linear lever is driven from the neutral position to the engaged position, it is driven in a flexible mode, where the movements of the cylindrical cam and the linear lever are disengaged. This allows one of the two cylindrical cams to move axially away from its end stop in the event of linear lever jamming, thereby compressing the spring mechanism to store driving force when the linear lever is jammed, and driving the linear lever to the engaged position via the expanding spring mechanism when the jamming is sufficiently reduced.

[0002] Shift actuators are used in motor vehicles to shift gears between two coaxially arranged rotating shafts in a transmission. In the engaged position, a rotational engagement is established between the two shafts, and torque is transmitted. In the neutral position, the two rotating shafts are disengaged. A typical application of this type of shift actuator is in a pawl clutch actuator. A pawl clutch is a mechanism for connecting and disconnecting two rotating shafts. Its operating principle is based on the engagement of a set of regularly spaced teeth or protrusions on a wheel connected to one shaft with complementary grooves between teeth on another wheel connected to the second shaft. When the two wheels move together such that the teeth of the first wheel are received in the grooves formed between the teeth of the second wheel, a slip-free rotational engagement is established between the shafts. For example, a pawl clutch actuator is described in US2015 / 0107955A1. A driven component, in the form of a nut, is connected to the shift fork and is used to drive the shift fork from neutral to gear engagement position when the lead screw is driven to rotate in a first rotational direction and a second rotational direction opposite to the first rotational direction, and vice versa. In the neutral position of the shift fork, one of the toothed wheels disengages from the other, thereby stopping the rotational engagement between the two wheels. By using the shift fork to move to the gear engagement position, the two toothed or claw-shaped wheels move into rotational interlocking, with the teeth of one wheel receiving in the grooves between the teeth of the other wheel.

[0003] In this type of shift actuator, it is possible that two toothed wheels or pawl wheels are positioned at an angle relative to each other, such that the teeth of one wheel are directly facing the teeth of the other wheel. In this case, the shift actuator cannot shift to the gear engagement position until the pawl wheels rotate relative to each other, so that the grooves between the pawls of one wheel and the pawls of the other wheel align.

[0004] WO 2023 / 165705 A1 discloses a shift actuator designed to handle temporary jamming of a linear lever for actuating a shift fork, and forms the basis of the preamble of claim 1. This known shift actuator can shift the linear lever from a center neutral position in a first direction to a first gear engagement position, and from neutral in the opposite direction to a second gear engagement position. The shift actuator includes a rotating member in the form of a hollow cylindrical sleeve, supported for rotatability but immovable in an axial direction defined by its axis of rotation, and an electric motor for rotating the hollow sleeve. The hollow sleeve is provided with two inwardly projecting cam followers aligned and spaced apart in the axial direction. Within the hollow sleeve, the two cylindrical cams are supported for axial movement but not rotation about the axis of rotation. Two opposing end stops are fixed to the linear rod at a predetermined axial distance, and two cylindrical cams are disposed between the two opposing end stops in a manner opposite to each other and coaxial with the axis of rotation. A spring mechanism is disposed between the two cylindrical cams to bias them apart, each toward a corresponding one of the two end stops. The two cylindrical cams are coupled to the linear rod, which extends coaxially with the axis of rotation. Each cylindrical cam has an outer cam surface configuration configured to cooperate with one of the two cam followers of the hollow sleeve, such that rotation of the hollow sleeve, and therefore rotational movement of the two cam followers, causes the cam followers to move along the cam surface configuration of the two cylindrical cams, driving the cylindrical cams to move in the axial direction, thereby moving the linear rod. The cam surface configuration of each cylindrical cam includes a helical cam groove in the outer end of each cylindrical cam opposite to the outer end of the other cylindrical cam, and rises toward the outer end of the corresponding cylindrical cam. At the inward end, the helical cam groove merges into the recessed surface sector of the corresponding cylindrical cam, leaving sufficient space for the cam follower entering this sector to move freely axially relative to the corresponding cylindrical cam. Two opposing cylindrical cams are angularly aligned with each other such that the helical cam groove portion of one of the two cylindrical cams aligns with the recessed surface sector of the other cylindrical cam. Thus, while one cam follower is entering and moving along the helical cam groove portion of one cylindrical cam, the other cam follower is entering and moving within the recessed surface sector of the other of the two cylindrical cams. In this way, the other cam follower freely follows within this recessed surface sector the axial movement of the linear rod caused by the cam follower engaged and driven by the helical cam groove of the driving cylindrical cam. In this way, as long as the linear rod does not experience high resistance sufficient to compress the spring mechanism, the axial movement of the linear rod is disengaged from the rotational movement of the cylindrical cam, meaning that the linear rod actually performs the axial movement driven by the rotation of the cylindrical cam.On the other hand, if the linear rod is jammed by high resistance, one of the two cam followers, which is driven by rotating the helical cam groove of the driving cylindrical cam along the associated cam follower, cannot move in the axial direction due to the jamming of the linear rod connected to it. In this case, the movement of the driving cam follower along the helical cam groove portion of the first cylindrical cam causes the driving cylindrical cam to move away from its end stop in the axial direction due to the jamming of the linear rod, thereby compressing the spring mechanism between the two cylindrical cams, while the second cam follower in the recessed surface sector of the second cylindrical cam freely follows this movement of the first cylindrical cam.

[0005] In the shift actuator arrangement of WO 2023 / 165705 A1, when the linear lever is driven from neutral to gear engagement, the spring mechanism between the two cylindrical cams is in the force transmission path, but when the linear lever moves from gear engagement to neutral, it is not in the force transmission path. In this way, the shift actuator is constructed such that when the linear lever is driven from engagement to neutral, it is driven in a rigid mode, in which the movements of the cylindrical cams and the linear lever are positively coupled, and when the linear lever is driven from neutral to engagement, it is driven in an elastic mode (i.e., the spring mechanism is in the force transmission path), in which the movements of the cylindrical cams and the linear lever are disengaged, such that in the event of linear lever jamming, one of the two cylindrical cams is driven axially away from its end stop, thereby compressing the spring mechanism to store driving force when the linear lever is jammed, and driving the linear lever to engagement through the expanding spring mechanism when the jamming is sufficiently reduced.

[0006] The object of this invention is to provide a shift actuator that does not use a hollow sleeve as an outer rotating member, and therefore can have a more compact design. Additionally, the object of this invention is to allow shifting between more than three shift states (first gear engaged, neutral, second gear engaged), that is, shifting sequentially between five or more shift positions (first gear engaged, first neutral, second gear engaged, second neutral, third gear engaged).

[0007] According to the invention, the rotating member is a shaft with a non-circular cross-section (e.g., a splined shaft with longitudinal grooves along its length), wherein the shaft extends coaxially with the axis of rotation through a central opening of complementary non-circular cross-sections in two cylindrical cams to provide torque-resistant engagement between the two cylindrical cams and the shaft, and to allow the two cylindrical cams to move axially along the shaft and be constrained by two end stops that are stationary relative to the shaft in the axial direction. Arranging the rotating member as a central axis radially located within the two cylindrical cams allows for a more compact design compared to the outer sleeve used as the rotating member in the prior art designs described above.

[0008] The linear rod is supported radially outward relative to the two cylindrical cams. The linear rod is provided with two inwardly pointing cam followers, which are fixed to the linear rod at axially spaced positions, wherein one of the two cam followers is received in the cam surface configuration of one of the two cylindrical cams, and the other is received in the cam surface configuration of the other of the two cylindrical cams.

[0009] The shift actuator is adapted to shift a linear lever within a sequence of shift states, wherein states of first gear engagement, first neutral, second gear engagement, second neutral, and third gear engagement follow each other in this linear sequence. Shifting in this sequence is achieved by a cam surface configuration of two cylindrical cams that cooperates with two cam followers of the linear lever, wherein the cam surface configuration of each cylindrical cam includes, in the circumferential sequence, the following cam surface features extending from the outer end of the respective cylindrical cam to the inner end of the adjacent spring mechanism: The first cam groove begins at the outer end, having a circumferentially extending cam groove end portion, followed by a helical drive cam portion that rises away from the outer end of the corresponding cylindrical cam, followed by a circumferentially extending cam groove end portion, which transitions to... The first recessed surface sector terminates the first cam groove, the first recessed surface sector having an increased width in the axial direction, wherein a corresponding one of the two cam followers is free to move in the axial direction, the first recessed surface sector being transitioned to The second cam groove extends from the first recessed surface sector (18), having a circumferentially extending cam groove end portion, followed by a helical drive cam portion that further ascends away from the outer end of the corresponding cylindrical cam, followed by a circumferentially extending cam groove end portion, which transitions to... The second cam groove terminates in a second recessed surface sector having an increased width in the axial direction, wherein a corresponding one of the two cam followers is free to move in the axial direction, and the second recessed surface sector transitions to... A circumferentially extended closed-end cam groove portion with a closed end.

[0010] The sequence of cam surface configurations for each cylindrical cam is as follows: starting from the outer end of the cylindrical cam furthest from the spring mechanism and the other cylindrical cam, the sequence consists of a first cam groove, a first recessed surface sector, a second cam groove, a second recessed surface sector, and continues to terminate the sequence with a circumferentially extended closed-end cam groove portion. The opposite orientation and rotational alignment of the two cylindrical cams mean that when one cam follower is located within the helical drive cam portion and thus driven axially, the other cam follower is located in one of the recessed surface sectors, such that the other cam follower disengages from its cylindrical cam and freely follows the axial movement determined by one of the cam followers.

[0011] The two cam followers of the linear lever are referred to below as the first cam follower and the second cam follower, and the two cylindrical cams are referred to as the first cylindrical cam and the second cylindrical cam, wherein the first cam follower is housed in the cam surface configuration of the first cylindrical cam, and the second cam follower is housed in the cam surface configuration of the second cylindrical cam, such that when referring to the first (second) cam follower with respect to the cam surface configuration features, it means that it refers to the first (second) cylindrical cam. Furthermore, when the motion of the first and second cam followers relative to the cam surface configuration of the first (second) cylindrical cam is often described below as the motion of the first (second) cam follower within and along the cam surface configuration, this is a description of the relative motion of the first and second cam followers, and it should be clear that in the stationary reference frame of the shift actuator, the first and second cam followers are stationary in rotation, while the first and second cylindrical cams rotate together with their cam surface configurations, and the first and second cam followers are driven only for axial motion.

[0012] More specifically, the cam surface construction of the two cylindrical cams and their rotational alignment relative to each other result in the following technical function. When the linear rod with its first cam follower is at the closed end of the circumferentially extended cam groove end portion of the first cam groove of the first cylindrical cam, the second cam follower is at the closed end of the circumferentially extended closed end cam groove portion of the second cylindrical cam (first stop engagement). As the current shaft rotates along the first and second cylindrical cams in the first rotation direction, the first cam groove of the first cylindrical cam rotates along the first cam follower, causing the first cam follower to enter the helical drive cam portion of the first cam groove, driving the linear rod toward the second cylindrical cam in the first axial direction. The second cylindrical cam rotates such that the second cam follower is already within the second recessed surface sector, allowing the second cam follower to move axially within the second recessed surface sector. Simultaneously, the first cam follower is further driven by the rotating helical drive cam portion, which ultimately guides the first cam follower to the circumferentially extended cam groove end portion of the first cam groove. This terminates the axial movement of the linear rod, and the second cam follower has passed through the second recessed surface sector and reached the entrance of the circumferentially extended cam groove end portion of the second cam groove (corresponding to the first neutral position).

[0013] As the first and second cylindrical cams continue to rotate in the first rotational direction, the first cam follower moves into the first recessed surface sector of the first cylindrical cam, while the second cam follower moves along the helical drive cam portion of the second cam groove. This helical drive cam portion drives the second cam follower and the linear rod to move further in the first axial direction, with the first cam follower positioned in the first recessed surface sector. During this phase, the linear rod is driven from the first neutral position to the second engagement position, with the first cam follower positioned in the first recessed surface sector. In the event of linear rod jamming, this will allow the first cam follower to displace within the first recessed surface sector of the first cylindrical cam, while the second cylindrical cam, as the helical drive cam portion rotates along the second cam follower, will displace away from its end stop, thereby compressing the spring mechanism and storing driving force until the jamming is sufficiently reduced. As the shaft continues to rotate, the first cam follower enters the entrance of the second cam groove from the first recessed surface sector, beginning at the end portion of the circumferentially extending cam groove, while the second cam follower approaches the end of the second cam groove in the end portion of the circumferentially extending cam groove at this stage. In this position, the linear lever is in the second stop engagement position.

[0014] As the first and second cylindrical cams rotate further from the second engagement position in the first rotational direction, the second cam groove rotates along the first cam follower, which is thus driven in the first axial direction by the helical drive cam portion of the second cam groove, while the second cam follower enters the first recessed surface sector of the second cylindrical cam in this manner. At this stage, the linear rod is driven toward the second neutral position, wherein the first cylindrical cam rigidly drives the linear rod toward the second neutral position with the first cam follower located in the helical drive cam portion. Finally, the first cam follower reaches the circumferentially extended cam groove end portion of the second cam groove, while the second cam follower reaches the circumferentially extended end portion of the first cam groove (this position corresponds to the second neutral position of the linear rod).

[0015] As the first and second cylindrical cams continue to rotate in the first rotational direction, the first cam follower enters the second recessed surface sector, while the second cam follower moves along the helical drive cam portion of the first cam groove. This is the drive phase that drives the linear lever to the third stop engagement position. During this drive phase, driving the linear lever to the stop engagement position is an elastic drive mode, meaning that in the event of linear lever jamming, the first cylindrical cam driving the first cam follower will be blocked by the jammed linear lever. This will cause the first cylindrical cam to displace away from its end stop, thereby compressing the spring mechanism to store the driving force of the first cylindrical cam on the first cam follower in the compressed state of the spring mechanism until the jamming is sufficiently reduced to allow the expanding spring mechanism to move the linear lever to the third stop engagement position. In any case, once the first cam follower reaches the closed end of the circumferentially extended closed end cam groove portion of the first cylindrical cam, and the second cam follower reaches the closed end of the first cam groove, corresponding to the third stop engagement position of the linear lever, the rotation of the first and second cylindrical cams in the first rotational direction terminates.

[0016] Due to the identical design of the first and second cylindrical cams, their opposite orientations, and rotational alignment, it is clear that when the linear lever has moved by rotating the cylindrical cams in the first rotational direction to finally reach the third gear engagement position as described above, rotating the two cylindrical cams in the second rotational direction opposite to the first rotational direction will cause the linear lever to move from the third gear engagement position through the aforementioned intermediate positions in the reverse order in the second axial direction opposite to the first axial direction, and finally return to the first gear engagement position.

[0017] In a preferred embodiment, the shaft is a splined shaft in the form of a cylindrical shaft, with a plurality of parallel grooves extending parallel to the axial direction on its outer surface; the central opening of the complementary shapes of the two cylindrical cams is a cylindrical opening with a plurality of elongated protrusions arranged to be received in the plurality of grooves of the splined shaft, thereby achieving, on the one hand, anti-torque engagement between the splined shaft and the two cylindrical cams, and on the other hand, allowing axial movement of the cylindrical cams relative to the splined shaft.

[0018] In a preferred embodiment, the two end stops are fixed to the shaft. In this way, the two end stops rotate together with the shaft, as do the two cylindrical cams, so that there is no relative rotational movement between the end stops and the two cylindrical cams that are biased against the two end stops by a spring mechanism.

[0019] In a preferred embodiment, the distance between the two end stops, the dimensions of the two cylindrical cams, and the dimensions of the spring mechanism are arranged such that the spring mechanism is under a predetermined preload and applies opposite forces to the two cylindrical cams to bias them against the two end stops. By establishing the predetermined preload on the spring mechanism, the level of resistance experienced by the linear lever as it moves toward the gear engagement position causes the driving force generated by the shift actuator to be converted into axial movement of one of the cylindrical cams without causing axial movement of the linear lever, and thus into increased spring compression to store driving force. In other words, the resistance experienced by the linear lever must exceed a threshold determined by the preload to induce axial shifting movement of the linear lever in the compression spring mechanism. Once the resistance experienced by the linear lever drops below the threshold, the spring mechanism begins to expand, thereby driving the linear lever to the gear engagement position.

[0020] In a preferred embodiment, a stop mechanism is implemented that resists any interfering forces acting on the linear rod attempting to pull it out of one of its engagement positions. To this end, each cylindrical cam has an increased cam groove width in the axial direction in the first, second, and third engagement positions of the linear rod; specifically, the circumferentially extended cam groove end portion of the first cam groove extending from the closed end, and the circumferentially extended closed end cam groove portion extending from the second recessed surface sector at the inner end of the cylindrical cam, have an increased width in the axial direction greater than the widths of the first and second cam followers. Furthermore, the two circumferentially extended cam groove end portions of the second cam groove have increased widths in the axial direction greater than the widths of the two cam followers. These increased widths are configured to establish free play for the linear rod in the axial direction in the first, second, and third engagement positions, with these circumferentially extended cam groove end portions merging into the first and second recessed surface sectors, respectively. This arrangement provides a stop mechanism that resists any interfering forces acting on the linear rod attempting to pull it out of one of the aforementioned engagement positions. When the linear lever is in one of the aforementioned engagement positions, the first cam follower of the linear lever is within the cam surface configuration of the first cylindrical cam, while the second cam follower of the linear lever is within the cam surface configuration of the second cylindrical cam. If the linear lever is in one of the aforementioned engagement positions, the free play of the cam followers in a defined region with increased axial width has the following effect: Due to the spring mechanism acting between the first and second cylindrical cams, the first and second cylindrical cams are pushed away from each other, causing the first and second cam followers to press against the inner walls of their respective cam groove regions, i.e., against the wall closer to the spring mechanism. If an external force is applied to the linear lever to move it away from the engagement position, the linear lever can follow this force within a finite distance (determined by the aforementioned free play), wherein this movement caused by the external force must overcome the force of the spring mechanism (the preload of the spring mechanism) and must compress the spring mechanism within the distance allowed by the free play of the first and second cam followers. In other words, any external force acting on the linear lever to move it away from one of the aforementioned engagement positions must compress the spring mechanism as the linear lever moves under this force, thus experiencing a gradually increasing reaction force attempting to return the linear lever to one of the aforementioned engagement positions. When the linear lever has moved away from one of the aforementioned engagement positions by the external force to the distance allowed by the free play of the first and second cam followers, it reaches a hard end stop, which prevents any further movement of the linear lever away from the engagement position. Therefore, the distance the linear lever can move away from one of the aforementioned engagement positions is limited by the hard end stop created by the free play limitation, and the additional compression of the spring mechanism caused by the movement of the linear lever establishes a return force that returns the linear lever to one of the aforementioned engagement positions once the interfering external force weakens.

[0021] In a preferred embodiment, the boundary wall of the second recessed surface sector, which defines the second recessed surface sector axially away from the inner end of the corresponding one of the first and second cylindrical cams, has a wall portion that rises toward the inner end of the corresponding cylindrical cam in a region near the inner end of the circumferentially extended closed-end cam groove portion, and a push protrusion pointing toward the inner end of the corresponding cylindrical cam is provided near the entrance of the circumferentially extended closed-end cam groove portion to apply a thrust to the corresponding one of the first and second cam followers as it moves toward and enters the circumferentially extended closed-end cam groove portion and passes through the push protrusion, so as to actively overcome potential jamming of the linear lever when approaching one of the first and third gear engagement positions.

[0022] The cam surface configuration of each cylindrical cam can be expanded by repeating the cam grooves and recessed surface sectors, thereby adding one more neutral and one more gear engagement position at one end of the sequence. In principle, this expansion can be further repeated, thus enabling a shift actuator with a sequence of (2n+1) shift positions having n≥3.

[0023] The invention will now be described with reference to the preferred embodiments shown in the accompanying drawings, wherein:

[0024] Figure 1 This is a perspective view of the shift actuator according to the present invention;

[0025] Figure 2 Corresponding to Figure 1 However, it is shown in partial cross-sectional view in the area enclosed by dashed lines;

[0026] Figure 3 This is a schematic table illustrating the shift state sequence available for the shift actuator of the present invention;

[0027] Figure 4 Showing the position Figure 3 A schematic side view of the shift actuator in the five shift states;

[0028] Figure 5 a) to k) show when from Figure 5 Shift to the first gear (G1) in a) Figure 5 A side view of the shift actuator in multiple successive rotational states during the third gear (G3) in the k);

[0029] Figure 6 a) to d) show the rotational state sequence when the shift actuator is driven from the second gear (G2) to the second neutral state;

[0030] Figure 7a) through e) show the rotational sequence of the linear lever driven by the shift actuator when the shift actuator is driven from the second neutral position to the third gear position and is temporarily stuck during the shift operation; and

[0031] Figures 8 to 10 These are schematic side views of the shift actuator in the second, third, and first gear shift positions, with enlarged schematic details shown at the top of the shift actuator.

[0032] Reference Figure 1 and Figure 2 This will describe the main components of the shift actuator, in which Figure 1 It is a three-dimensional side view. Figure 2 Is it like this? Figure 1 The image shows a side view, but is shown as a partial sectional view in the area enclosed by the dashed rectangle. The shift actuator includes a rotating member in the form of a shaft 4, which in the preferred embodiment is a splined shaft 4, as shown. Figure 2 Most clearly visible is the longitudinal groove extending parallel to the axial direction along the spline shaft 4. Shaft 4 is supported so that it can rotate with its central axis coinciding with the axis of rotation, wherein... Figure 2 On the left-hand side, a ball bearing can be seen, indicating the rotary support for shaft 4. Shaft 4 is also supported for stationary motion in the axial direction. Figure 1 As shown, an electric motor is provided, which is operable to drive a shaft 4 to rotate about its axis of rotation in a first direction of rotation or in the opposite second direction of rotation via a set of gears, such as... Figure 1 and Figure 2 The curved arrow in the image indicates this.

[0033] The shift actuator also includes a first cylindrical cam 1 and a second cylindrical cam 2. The two cylindrical cams have the same design but are arranged in opposite orientations, such that similar ends of the two cylindrical cams are located at their facing inner ends, and similar outer ends of the two cylindrical cams are opposite to each other at their opposite outer ends. Each of the two cylindrical cams 1 and 2 has a through-center opening for receiving a shaft 4 extending through the center opening of the two cylindrical cams 1 and 2. The center opening of the two cylindrical cams has a cross-sectional shape complementary to the cross-sectional shape of the splined shaft 4, thereby forming a spline engagement between the shaft 4 and the two cylindrical cams 1 and 2. This engagement provides, on the one hand, a torque-resistant engagement of the two cylindrical cams 1 and 2 on the shaft 4, while on the other hand, the two cylindrical cams are capable of sliding axially along the shaft 4. The axial movement of the two cylindrical cams 1 and 2 is restricted by two opposing, spaced-apart end stops 5 and 6, which are stationary in the axial direction, wherein, in the illustrated embodiment, the two opposing end stops 5 and 6 are fixed to the shaft 4. A spring mechanism 7 acts between the two cylindrical cams 1 and 2, which pushes the two cylindrical cams 1 and 2 apart in opposite axial directions, each toward its associated end stops 5 and 6. Since the cylindrical cams 1 and 2 and the end stops 5 and 6 all rotate with the shaft 4, there is no friction between the end stops 5 and 6 and the cylindrical cams 1 and 2 when the shaft 4 rotates.

[0034] Each of the two cylindrical cams 1 and 2 has a cam surface configuration comprising a first cam groove 10, followed by a first recessed surface sector 18, and then a second cam portion 20 that merges into a second recessed surface sector 28. This cam surface configuration of the two cylindrical cams is coordinated with two cam followers 31 and 32, the coordination of which will be described in more detail below, wherein the first cam follower 31 is accommodated in the cam surface configuration of the first cylindrical cam 1, and the second cam follower 32 is accommodated in the surface configuration of the second cylindrical cam 2.

[0035] Two cam followers 31 and 32 are axially aligned and axially spaced apart from each other and fixed to a linear rod 30. The linear rod 30 is radially supported outside the two cylindrical cams, wherein the linear rod 30 is supported such that it can move in an axial direction parallel to the axis of rotation of shaft 4. Figure 1 and Figure 2 The two arrows indicate movement in opposite axial directions. The two cam followers 31 and 32 are connected to the linear rod so that they protrude inward, thereby extending into the respective cam surface configurations of the two cylindrical cams 1 and 2 as described above.

[0036] Figure 3This is a schematic diagram illustrating the linear sequence of shift positions of the linear lever corresponding to the shift states of first gear G1, first neutral N1, second gear G2, second neutral N2, and third gear G3. The shift actuator is operable to move the linear lever from one of the aforementioned shift positions to any adjacent shift position indicated by the arrow. There are two types of horizontal arrows: arrows completely filled in black and arrows shown only in black outlines. These two different types of arrows represent different shift characteristics. The completely black arrows are assigned to shift movements from one of the gear engagement positions to one of the neutral positions, and these shift movements are performed in a "rigid" shift mode, in which the axial movement of the linear lever is strictly coupled to the rotational movement of two cylindrical cams. The shifting movements indicated by the arrows with black outer lines are associated with shifting from one of the neutral positions to one of the gear engagement positions, and these shifting movements are performed in a "flexible" or "compliant" shifting mode. In this flexible shifting mode, the axial movement of the linear lever is not strictly coupled (associated) with the rotational movement of the cylindrical cams, but is partially disengaged in the following sense: if the linear lever encounters low resistance and the force preventing its linear movement is below a threshold, the linear movement of the lever is performed; if the resistance is above the threshold, the linear lever is stuck and does not move in the axial direction. As a result of this stuck state, one of the two cylindrical cams attempting to drive the linear lever in the axial direction, in response to the stuck state of the linear lever, is forced to move in the opposite axial direction along the axis by a driving force, thereby moving it away from its associated end stop and closer to the other opposite cylindrical cam, thus compressing the spring mechanism 7 between the two cylindrical cams 1 and 2. In other words, in this flexible or compliant shifting mode, the spring mechanism 7 is in the force transmission path between the shaft 4 and the linear lever 30. If the resistance or jamming force experienced by the linear lever exceeds a threshold, the linear lever does not move axially. Instead, the driving force of the mechanism is redirected to its axial displacement via one of the drive cylindrical cams 1 and 2. This axial displacement compresses the spring mechanism 7, thereby storing the accumulated driving force for the linear lever in the compressed state of the spring mechanism 7. Once the resistance or jamming force weakens below the threshold, the spring mechanism 7 expands, thereby driving the linear lever 30 to the desired gear engagement position. In other words, the jammed axial movement of the linear lever into the desired gear engagement position is converted into compression of the spring mechanism, thus storing the driving force. The desired linear movement of the linear lever 30 is executed in a delayed manner when the resistance or jamming force has sufficiently decreased to allow the compressed spring mechanism 7 to expand again. The spring mechanism 7 then moves the linear lever to the desired gear engagement position, thus compensating for the previous jammed movement. How the characteristics of the two different shifting modes are achieved through the cam surface construction of the two cylindrical cams will be described in more detail below.

[0037] Figure 4a) to e) show schematic side views of the shift actuators in the aforementioned five shift states G1-G3. Figure 4 In (a), the linear lever 30 is in the first stop engagement position, in which the first cam follower 31 is located in the circumferentially extending cam groove end portion 12 of the first cam groove extending from the closed end 11. The second cam follower 32 is located in the circumferentially extending closed end cam groove portion 29, which merges into the second recessed surface sector 28 of the cam surface configuration of the second cylindrical cam 2.

[0038] exist Figure 4 In (b), the shaft and the two cylindrical cams 1 and 2 have rotated in the first rotational direction, causing the linear lever 30 to move axially to the shift position corresponding to the first neutral gear. During this rotation, the first cam follower 31 has moved from the closed end 11 of the first cam groove 10 along the circumferentially extending cam groove end portion 12, and further along the helical drive cam portion 13 of the first cam groove (see...). Figure 4 c) movement. As the cylindrical cam rotates further, the first cam follower 31 has reached the circumferentially extended cam groove end portion 14 of the first cam groove 10. Simultaneously, the second cam follower 32 has moved away from the circumferentially extended closed end cam groove portion 29 and entered the second recessed surface sector 28 of the second cylindrical cam 2. The second recessed surface sector 28 allows axial movement of the second cam follower 32, such that as the first cam follower 31 is climbing along the helical drive cam portion 13, the second cam follower 32 can be displaced axially within the second recessed surface sector 28. When the first cam follower 31 passes through the helical drive cam portion 13 and reaches the subsequent circumferentially extended cam groove end portion 14 of the first cam groove, the second cam follower 32 passes through the second recessed surface sector 28 and enters the adjacent circumferentially extended cam groove end portion 24 of the second cam groove 20 of the second cylindrical cam, as... Figure 4 As shown in b).

[0039] For the first gap ( Figure 4 b)) to the second gear engagement ( Figure 4In the next shift operation of c), shaft 4 and the two cylindrical cams rotate again in the same direction of rotation as before, wherein this rotation causes the second cam groove of the second cylindrical cam 2 to pass along the second cam follower 32 with the helical drive cam portion 23 of the second cam groove, while causing the first cam follower 31 to move through the first recessed surface sector 18. In this way, the second cam follower 32 is driven to move axially by the rotating helical cam drive portion 23 of the second cam groove of the cylindrical cam 2, while the first cam follower 31 is in the first recessed surface sector 18 of the cylindrical cam 1 at this stage, and therefore freely follows the axial movement driven by the second cam follower 32. After passing along the helical drive cam portion 23, the second cam follower 32 reaches the subsequent circumferentially extended cam groove end portion 22 of the second cam groove of the cylindrical cam 2 as it rotates further. Figure 4 In the rotational state shown in c), the first cam follower 31 has passed through the first recessed surface sector 18 of the cylindrical cam 1 and has entered the circumferentially extending cam groove end portion 22 of the second cam groove of the cylindrical cam 1, such that the linear rod 30 has reached Figure 4 c) shows the second gear engagement position. If used for... Figure 4 b) to Figure 4 In the rotational motion of shifting from neutral to second gear (c), if the linear lever 30 jams, the driving force exerted by the cylindrical cam 2's helical drive cam portion 23 rotating along the second cam follower 32 is converted into a displacement of the cylindrical cam 2 in the opposite direction, thereby compressing the spring mechanism 7. Therefore, from Figure 4 b) to Figure 4 c) The shifting operation from neutral 1 to second gear engagement is performed in a flexible or smooth manner as previously described. The shifting operation from neutral to gear engagement position will be referred to below. Figure 7 A more detailed description of a) through e).

[0040] When the cylindrical cams 1 and 2 are rotated one step further in the same direction of rotation, the operation is performed from... Figure 4 c) The second gear engages G2 to Figure 4During the next shift operation of the second neutral N2 in d), the driving force is generated by the helical drive cam portion 23 of the second cam groove of the cylindrical cam 1 passing along the first cam follower 31. This helical drive cam portion 23 drives the first cam follower axially, while the second cam follower 32 is located in the first recessed surface sector 18 of the cylindrical cam 2 and thus freely follows the axial movement driven by the first cylindrical cam 1. After the helical drive cam portion 23 has passed along the first cam follower 31, the circumferentially extended cam groove end portion 24 of the second cam groove has reached the first cam follower 31, and the second cam follower 32 has entered the circumferentially extended cam groove end portion 14 of the first cam groove of the cylindrical cam 2, as... Figure 4 As shown in d), the linear lever 30 has thus reached the position corresponding to the second neutral position. This shifting operation from gear engagement to neutral position is performed in a rigid manner, that is, driven by the second cam follower 32 along the helical drive cam portion 23 of the second cam groove of the cylindrical cam 2, while the spring mechanism 7 is not in the force transmission path.

[0041] From the second gap ( Figure 4 d)) to the third gear engagement ( Figure 4 In the final shift operation of e), the cylindrical cams 1 and 2 rotate again in the first rotational direction. In this case, the cylindrical cam 2 first rotates along the second cam follower 32 with the circumferentially extended cam groove end portion 14, and then rotates along the second cam follower 32 with the helical drive cam portion 13 of the first cam groove of the cylindrical cam 2. This causes the linear lever to move further in the axial direction, where the first cam follower 31 is located in the second recessed surface sector 28 of the cylindrical cam 1 and is therefore able to follow the axial movement driven by the second cam follower 32. Finally, the further rotation of the cylindrical cams 1 and 2 causes the second cam follower 32 to pass along the circumferentially extended cam groove end portion 12 to the closed end 11 of the first cam groove of the cylindrical cam 2, and the first cam follower 31 has passed through the second recessed surface sector 28 of the cylindrical cam 1 and finally reaches the circumferentially extended closed end cam groove portion 29 adjacent to the second recessed surface sector 28 at the inner end of the cylindrical cam 1. In this way, the linear lever 30 has reached Figure 4The third gear engagement position G3 is shown in (e). Again, it should be noted that this shift from neutral to gear engagement is performed in a responsive or compliant shifting mode because when the helical drive cam portion 13 of the first cam groove of the cylindrical cam 2 rotates along the second cam follower 32 to drive the linear lever 11, the spring mechanism 7 is in the force transmission path. This means that if the linear lever is stuck during this driving phase, and the cylindrical cam 2 rotates along the second cam follower together with the helical drive cam portion 13, the cylindrical cam 2 can react by displacement in the opposite axial direction along with the compression of the spring mechanism 7. This results in the driving force being elastically stored in the compressed spring mechanism, which would otherwise be released after the linear lever's sticking is sufficiently reduced. The expanding spring mechanism thereafter completes the expected shift to the third gear engagement position G3.

[0042] Due to the identical design of cylindrical cams 1 and 2, it is clear that when from Figure 4 Starting from the third gear engagement state shown in e), when the shifting operation is performed by rotating the cylindrical cams 1 and 2 in the second and opposite rotational directions, the linear lever 30 will shift through shift states N2, G2, N1, and G1 in opposite axial directions in the opposite manner to finally reach the corresponding gear. Figure 4 The first gear engagement position of G1 is shown in a). Similarly, it is clear that instead of a sequential shifting operation sequence in one axial direction, shifting operations can also be combined such that the linear lever moves from... Figure 4 Any shift position shown in b) to d) shifts towards the adjacent shift position in either of the two axial directions. Therefore, any successive series of shift positions selected from the group consisting of shift positions G1, N1, G2, N2 and G3 can be achieved by this shift actuator when the rotational direction of the cylindrical cams 1 and 2 is properly controlled in subsequent shift operations.

[0043] Figure 5 a) to k) show the rotational step sequence of the shift actuator, wherein one or two intermediate rotational steps are shown between adjacent shift positions G1, N1, G2, N2, and G3. In particular, Figure 5 a) corresponds to, for example Figure 4 In a), the first gear engages G1. Figure 5 d) corresponds to, for example Figure 4 The first gap N1 in b) Figure 5 f) corresponds to, for example Figure 4 In c), the second gear engages G2. Figure 5 h) corresponds to such Figure 4 The second neutral N2 in d), and Figure 5 k) corresponds to, for example Figure 4 The third gear in (e) engages G3. (Refer to the above.) Figure 4The descriptions of shifting operations in sections a) to e) can also be combined with... Figure 5 Read the sequence from a) to k) to gain a better understanding of the cam surface construction of cylindrical cams 1 and 2.

[0044] Reference Figure 6 From a) to d), the single gear shift operation from second gear G2 to second neutral N2 will now be described. Figure 6 In (a), the linear lever is in the second stop engagement position, wherein in this state, the first cam follower 31 is located in the circumferentially extended cam groove end portion 22 of the second cam groove 20, and the second cam follower 32 is located in the circumferentially extended cam groove end portion 24 of the second cam groove 20. When the shaft rotates together with the cylindrical cams 1 and 2, the first cylindrical cam 1 rotates along the first cam follower 31 with its helical drive cam portion 23 of its second cam groove, thereby driving the cam follower 31 in the axial direction. At the same time, the second cam follower 32 has left the circumferentially extended cam groove end portion 24 and entered the first recessed surface sector 18, such as Figure 6 As shown in b). Figure 6 As can be seen in b) and c), the wall 35 forming the boundary of the first recessed surface sector 18 has a spiral shape that rises toward the outer end of the cylindrical cam 2, thereby forming a spiral track on which the second cam follower 32 slides. This spiral wall 35 and the spiral drive cam portion 23 of the second cam groove have the same slope, such that both cam followers 31 and 32 are driven. As rotation continues, the first cam follower 31 has passed through the spiral drive cam portion 23 and... Figure 6 In d), the second cam follower 32 reaches the circumferentially extended cam groove end portion 24 of the second cam groove, while the second cam follower 32 has left the spiral wall 35 and entered the first cam groove of the cylindrical cam 2 through the circumferentially extended cam groove end portion 14 of the first cam groove, so that in approach Figure 6 When the rotational motion at the endpoint position in d) ends, the cam followers 31 and 32 are no longer driven in the axial direction, and the linear rod 30 reaches the second neutral position N2. This shifting process from the second gear to the second neutral is a rigid shifting operation because the first cam follower is driven directly by the helical cam drive part 23, and the spring mechanism 7 is not in the force transmission path.

[0045] Now refer to Figure 7a) through e) describe the next shift operation from second neutral to third gear engagement in the same axial direction, where in this example the linear lever 30 is temporarily stuck. At the start of the shift operation, the first cam follower 31 is in the circumferentially extended cam groove end portion 24 of the second cam groove of the cylindrical cam 1, and the second cam follower 32 is in the circumferentially extended cam groove end portion 14 of the first cam groove of the cylindrical cam 2. Shortly after the rotation of the cylindrical cams 1 and 2 begins, the second cam follower 32 has reached the helical drive cam portion 13 of the first cam groove (see...). Figure 7 (b)), while the first cam follower 31 has reached the second recessed surface sector 28 of the cylindrical cam 1. As the cylindrical cams 1 and 2 continue to rotate, the helical drive cam portion 13 continues to rotate along the second cam follower 32 (b). Figure 7 c) In this case, the linear rod 30 is stuck and therefore cannot move in the axial direction. Therefore, the driving force of the helical drive cam portion 13 rotating against the second cam follower 32 is not transmitted as axial movement of the linear rod, but as axial movement of the cylindrical cam 2 in the opposite axial direction, causing the cylindrical cam 2 to move away from its end stop 6, as can be seen from the gap between the outer end of the cylindrical cam 2 and the end stop 6. This axial displacement of the cylindrical cam 2 compresses the spring mechanism 7, thereby storing driving force through the continuous compression of the spring mechanism 7. During this stage, the first cam follower 31 is in the second recessed surface sector, and due to the axial movement of the linear rod being stuck, the first cam follower remains close to the lower wall of the second recessed surface sector 28, and moves along this circumferentially extending lower wall during further rotation from 7c) to 7d), wherein during this movement phase, the linear rod 30 is still stuck, causing the spring mechanism 7 to compress further, and the gap between the outer end of the cylindrical cam 2 and the end stop 6 to increase further. Figure 7 In d), the second cam follower 32 has reached the circumferentially extended cam groove end portion 12 of the first cam groove. Now assume the linear rod is stuck in Figure 7 The motion between states d) and e) stops spontaneously at some point. In this case, the compressed spring mechanism expands, thereby pushing the cylindrical cam 2 axially toward its end stop 6, thus closing the previously formed gap and driving the linear lever to... Figure 7 The third gear engagement position (e). To support the direction towards Figure 7 e) During the final stage of rotation in the third gear engagement position, the linear lever is released from its jamming, and the second recessed surface sector 28 of the cylindrical cam 1 is provided with a push protrusion 40 near the inlet of the circumferentially extending closed end cam groove portion 29. In the cylindrical cams 1 and 2 from Figure 7In the final stage of rotation from d) to e), the second cam follower 32 slides onto the lower wall of the second recessed surface sector 28 and slides along the push protrusion 40, thereby pushing axially toward the third engagement position, thus actively supporting the release of the linear rod 30 from its jamming. In the finally reached third engagement position, the first cam follower 31 thus reaches the circumferentially extended closed end cam groove portion 29 of the cylindrical cam 1, while the second cam follower 32 reaches the closed end 11 of the first cam groove 10 at the outer end of the cylindrical cam 2.

[0046] The following describes a stop mechanism that holds a linear lever in the gear engagement position and, in the event of an interference force attempting to move it away from the gear engagement position, pushes the linear lever back to the centered gear engagement position. Figure 8 The lower part of the diagram schematically shows a side view of the shift actuator, wherein the shift actuator is in the second gear engagement position, the first cam follower 31 is located in the end portion 22 of the circumferentially extending cam groove, and the second cam follower 32 is located in the end portion 22 of the circumferentially extending cam groove of the cylindrical cam 2. Figure 8 As indicated, in the stop engagement position of the first and second cam followers 31, 32, the circumferentially extended cam groove end portion 22 is provided with a recess or groove 22' on its outer side wall, such that in this region of the recess 22', the circumferentially extended cam groove end portion 22 has an increased width.

[0047] exist Figure 8 In the image, enlarged details are shown within the dashed rectangle above the shift actuator. In this detail, two opposing cylindrical cams 1 and 2, first and second cam followers 31 and 32, and spring mechanism 7 are shown in a highly schematic manner. The recess 22' in the circumferentially extending cam groove end portion 22 in the second gear engagement position is also shown in an exaggerated manner. Under normal conditions, when the shift actuator is in such a position… Figure 8 When the second gear is engaged, the preload of the spring mechanism 7 pushes the first cylindrical cam 1 and the second cylindrical cam 2 apart, so that the first and second cam followers 31 and 32 are in the second gear engagement position. Figure 8 The position is indicated by a solid circle in the middle detail. As shown, the first cam follower 31 and the second cam follower 32 have a certain amount of free play in the axial direction created by the recess 22'. If an external force acts on the linear rod, attempting to pull it out of the second stop engagement position toward the first or second neutral position, this force must overcome the preload of the spring mechanism 7, thereby pulling one of the first and second cylindrical cams 1 and 2 closer to the other. If such a force acts on the linear rod and pulls the first cylindrical cam 1 closer to the second cylindrical cam 2, the second cam follower 32 will displace the same distance and move into the recess 22', at a position where... Figure 8The details are indicated by the dashed circle (if the linear lever is pulled in the opposite direction, bringing the second cylindrical cam 2 closer to the first cylindrical cam 1, the first cam follower 31 moves to the position indicated by the dashed circle in the recess 22' of the cylindrical cam 1). Ultimately, the second cam follower 32 will contact the bottom of the recess 22', which forms a hard-end stop, preventing the linear lever from being pulled further away from the second stop engagement position. Therefore, in any case, further displacement of the linear lever from the vicinity of the second stop engagement position is prevented (the extent of this vicinity is determined by the degree of free play of the cam follower in the axial direction).

[0048] Once the disturbance force acting on the linear rod stops, the compression of the spring mechanism 7 caused by pulling the cylindrical cams 1 and 2 closer together will be released by the expansion of the spring mechanism 7, so that the push rod with its first and second cam followers 31 and 32 will once again reach the position indicated by the first and second cam followers 31 and 32 in the solid circle, which corresponds to the central second stop engagement position of the linear rod.

[0049] The function of the stop mechanism is Figure 8 The enlarged details schematically show that it is represented by a spring between two spaced vertical lines and a center line between them. The center vertical line indicates the axial position of the linear lever. If the linear lever is subjected to an external disturbance force and thus displaces, and if this force pulls the two cylindrical cams 1, 2 closer together, the spring mechanism 7 is compressed. Therefore, any external force that causes the linear lever to displace from its central position must resist the spring force of the spring mechanism 7, which is indicated by the springs on either side of the center vertical line when the linear lever displaces in either direction. The two outer vertical lines show the hard-end stop reached when one of the two cam followers 31, 32 displaces to the bottom of the contact recess 22' in the recess 22', thus acting as a hard-end stop to stop any further displacement of the linear lever. Once the disturbance force weakens, the compressed spring mechanism 7 will release, thereby returning the linear lever to the centered second-position engagement position.

[0050] Figure 9 It corresponds to Figure 8 However, regarding the illustration of the first gear engagement position, in this case, the first cam follower 31 is located at the closed end 11 of the first cam groove at the outer end of the cylindrical cam 1. The second cam follower 32 is located at the circumferentially extending closed end cam groove portion 29 adjacent to the second recessed surface sector 28 of the cylindrical cam 2. The closed end 11 includes a recess or protrusion 11' in its wall pointing towards the outer end of the cylindrical cam 1, which provides additional space in the axial direction. Similarly, the closed end cam groove portion 29 includes a recess or protrusion 29' in its wall facing the outer end of the cylindrical cam 2, which creates free play for the second cam follower in the axial direction. Again, in Figure 9The upper part shows enlarged details, in which the recesses or protrusions 11′ and 29′ are... Figure 9 The lower illustration is exaggerated. The function and reference of the stopping mechanism in this position are shown. Figure 8 The description is the same. That is, the preload of the spring mechanism 7 keeps the linear rod centered in the first stop engagement position, and the spring mechanism 7 generates a gradually increasing reaction force to resist any external force that might push the linear rod away from its centered position, and finally, any further displacement of the linear rod from the area adjacent to the centered position is limited by a hard stop when one of the first and second cam followers 31, 32 contacts the bottom of the corresponding one of the recesses 11' and 29'.

[0051] Figure 10 A stop mechanism for the third engagement position is shown, wherein a first cam follower 31 is located at the circumferentially extended closed end cam groove portion 29 of the cylindrical cam 1, and a second cam follower 32 is located at the closed end 11 of the first cam groove at the outer end of the cylindrical cam 2. This situation is similar to... Figure 9 The first gear engagement position shown is symmetrical, and it is clear that the function of the stop mechanism is the same as that previously described for the first and second gear engagement positions. List of reference numerals 1 First cylindrical cam 2 Second cylindrical cam 4-axis 5 and 6 end stops 7. Spring Mechanism 8 Electric motors 10 First Cam Groove 11. The closed end of the first cam groove at the outer end of the cylindrical cam. 12 The circumferentially extending cam groove end portion of the first cam groove extending from the closed end 13 The helical drive cam section of the first cam groove 14 The circumferentially extended cam groove end portion merged into the first cam groove in the first recessed surface sector 18 First recessed surface sector 20 Second Cam Groove 22 The circumferentially extending cam groove end portion of the second cam groove extending from the first recessed surface sector 23 The helical drive cam section of the second cam groove 24 The circumferentially extended cam groove end portion that merges into the second cam groove in the second recessed surface sector 28 Second recessed surface sector 29. The circumferentially extended closed end cam groove portion adjacent to the second recessed surface sector at the inner end of the cylindrical cam. 30 linear rods 31 First Cam Follower 32 Second Cam Follower 35 Spiral Wall Track 40. Promote the prominent parts

Claims

1. A shift actuator for driving a linear lever (30) to actuate a shift fork, comprising: A rotating member, the rotating member being supported so as to be able to rotate, but not to move in the axial direction defined by its axis of rotation; An electric motor (8) is used to rotate the rotating member, wherein the linear rod (30) is driven by the rotational motion of the rotating member to move linearly parallel to the axial direction. The rotating member is driven by two cylindrical cams (1, 2) having the same design and supported for movement in the axial direction. The two cylindrical cams are arranged between two opposing end stops (5, 6) in a manner that is oriented opposite to each other, rotates relative to each other, and is coaxial with the axis of rotation. The stops are positioned relative to each other at a fixed axial distance; a spring mechanism (7) is disposed between the two cylindrical cams (1, 2) to bias the two cylindrical cams apart toward a corresponding one of the two end stops (5, 6), wherein each of the two cylindrical cams (1, 2) is provided with an outer cam surface configuration configured to cooperate with one of the two cam followers, such that the two cylindrical cams (1, 2) and the spring mechanism (7) therebetween cooperate with the linear rod (30). Such that when the rotating member is driven to rotate first along a first rotation direction and then along a second rotation direction opposite to the first rotation direction, the linear rod (30) is driven from the neutral position to the engaged position and back to the neutral position along the axial direction in the first direction, and when the rotating member is driven to rotate first along the second rotation direction and then along the first rotation direction, the linear rod (30) moves from the neutral position to another engaged position and back to the neutral position in the second direction opposite to the first direction, and When the linear rod (30) is driven from the engaged position to the neutral position, the linear rod (30) is driven in a rigid mode, in which the movements of the cylindrical cam and the linear rod are linked. When the linear rod (30) is driven from the neutral position to the engaged position, the linear rod (30) is driven in an elastic mode, in which the movements of the cylindrical cam and the linear rod are disengaged. This allows one of the two cylindrical cams (1, 2) to displace away from its end stop (5, 6) along the axial direction in the event of jamming, thereby compressing the spring mechanism (7) to store driving force when the linear rod (30) is jammed, and driving the linear rod to the engaged position through the expanding spring mechanism once the jamming is sufficiently reduced. Its features are, The rotating member is a shaft (4) having a non-circular cross-section, which extends coaxially with the axis of rotation through the central opening of the complementary non-circular cross-sections of the two cylindrical cams (1, 2) to provide torque-resistant engagement between the two cylindrical cams (1, 2) and the shaft (4), and to allow the two cylindrical cams to move axially along the shaft (4) under the constraint of the two end stops (5, 6) which are stationary relative to the shaft in the axial direction. The linear rod (30) is radially outwardly supported relative to the two cylindrical cams (1, 2) and is provided with the two cam followers (31, 32). The two cam followers are fixed to the linear rod at axially spaced positions and protrude inward. One of the cam followers (31) is housed in the cam surface structure of one of the cylindrical cams (1), and the other cam follower (32) is housed in the cam surface structure of the other cylindrical cam (2). The shift actuator is adapted to shift the linear lever (30) within a sequence of shift states, in which a first gear engagement state, a first neutral state, a second gear engagement state, a second neutral state, and a third gear engagement state follow each other. In this sequence, gear shifting is achieved through the cam surface configuration, which, for each of the two cylindrical cams (1, 2), extends circumferentially from the outer end of the corresponding one of the two cylindrical cams (1, 2) to the inner end adjacent to the spring mechanism (7): The first cam groove (10) has a circumferentially extending cam groove end portion (12) starting from the closed end (11) at the outer end, followed by a helical drive cam portion (13) that rises away from the outer end of the corresponding one of the two cylindrical cams (1, 2), followed by a circumferentially extending cam groove end portion (14), and the first cam groove (10) terminates at the circumferentially extending cam groove end portion and transitions to: A first recessed surface sector (18) with an increased width in the axial direction, in which one of the two cam followers (31, 32) is able to move freely in the axial direction, the first recessed surface sector (18) transitions to: A second cam groove (20) extending from the first recessed surface sector (18) has a circumferentially extending cam groove end portion (22), followed by a helical drive cam portion (23) that further ascends away from the outer end of the corresponding one of the two cylindrical cams (1, 2), followed by a circumferentially extending cam groove end portion (24), at which point the second cam groove terminates and transitions to: A second recessed surface sector (28) with an increased width in the axial direction, in which one of the two cam followers (31, 32) is able to move freely in the axial direction, the second recessed surface sector (28) transitions to: A circumferentially extended closed-end cam groove portion (29) with a closed end.

2. The shift actuator according to claim 1, characterized in that, The shaft (4) is a splined shaft in the form of a cylindrical shaft, including a plurality of parallel grooves extending parallel to the axial direction, and the central opening of the complementary shape of the two cylindrical cams (1, 2) is a cylindrical opening with a plurality of elongated protrusions arranged to be received in the plurality of grooves of the splined shaft to provide torque-resistant engagement between the splined shaft (4) and the two cylindrical cams (1, 2) and allow axial movement of the cylindrical cams relative to the splined shaft.

3. The shift actuator according to claim 1 or 2, characterized in that, The two end stops (5, 6) are fixed to the shaft (4).

4. The shift actuator according to any one of the preceding claims, characterized in that, The distance between the two end stops (5, 6), the dimensions of the two cylindrical cams (1, 2) and the dimensions of the spring mechanism (7) between them are arranged such that the spring mechanism (7) is under a predetermined preload and applies forces in opposite directions to the two cylindrical cams (1, 2) to bias them against the two end stops (5, 6).

5. The shift actuator according to any one of the preceding claims, characterized in that, For each of the two cylindrical cams (1, 2), the circumferentially extending cam groove end portion (12) of the first cam groove (10) extending from the closed end (11) and the circumferentially extending closed end cam groove portion (29) extending from the second recessed surface sector (28) at the inner end of the cylindrical cam have a width that is increased in the axial direction and is greater than the width of the first cam follower and the second cam follower (31, 32). Furthermore, the circumferentially extended cam groove end portions (22, 24) of the second cam groove (20) which are respectively adjacent to the first recessed surface sector and the second recessed surface sector (18, 28) have a width that is increased in the axial direction and is greater than the width of each of the two cam followers (31, 32). The increased width is configured to establish free play for the linear rod in the axial direction in the first gear engagement position, the second gear engagement position and the third gear engagement position.

6. The shift actuator according to any one of the preceding claims, characterized in that, The boundary wall of the second recessed surface sector (28), which defines the second recessed surface sector (28) at the inner end of the corresponding one of the first and second cylindrical cams (1, 2) in the axial direction away from the inner end of the corresponding cylindrical cam, is provided in the region of the circumferentially extended closed end cam groove portion (29) near the inner end of the corresponding cylindrical cam. It is provided with a wall portion that rises toward the inner end of the corresponding cylindrical cam (1, 2), and a push protrusion (40) pointing toward the inner end of the corresponding cylindrical cam (1, 2) is provided near the entrance of the circumferentially extended closed end cam groove portion (29) to apply a thrust to the corresponding cam follower when the corresponding one of the first and second cam followers (31, 32) moves toward and into the circumferentially extended closed end cam groove portion (29) and passes the push protrusion (40) to actively overcome the potential jamming of the linear rod when the linear rod approaches one of the first gear engagement position and the third gear engagement position (G1, G3).

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