Gear shift assist device and shifting device for a motorcycle

Abstract

Gear shift assist device, in particular for a motorcycle, comprising a housing (16), a piston (12) arranged in the housing (16) and at least one compression spring (20, 26) provided in the housing (16), wherein the piston (12) is displaceable relative to the housing (16) under compression of at least the compression spring (20, 26), characterized in that a locking device (38) designed separately from the compression spring or springs (20, 26) is provided, which secures the piston (12) in a neutral position relative to the housing (16) below a predetermined unlocking force exerted on the piston (12) or the housing (16).

Description

[0001] The invention relates to a transmission shift assist device, particularly for a motorcycle, comprising a housing, a piston arranged in the housing, and at least one compression spring provided in the housing, wherein the piston is displaceable relative to the housing under compression from at least one compression spring. The invention further relates to a shifting device for a motorcycle with such a transmission shift assist device.

[0002] A generic transmission shift assist device is known, for example, from DE 10 2010 015 037 A1 and enables the rider, particularly on high-performance motorcycles, to shift gears quickly without using the clutch. For this purpose, the device, also referred to as a shift assist, is arranged between a foot shift lever of the shifting mechanism and the transmission input. As is known, to shift from the current gear to the next higher gear, the foot shift lever is pulled upwards, while pushing the shift lever downwards shifts sequentially into lower gears. The transmission shift assist device, arranged between the foot shift lever and the transmission input, detects the shifting force exerted by the rider's foot by registering a relative displacement between the piston and the housing, which occurs with corresponding compression of the pressure spring that determines the force level, using a displacement sensor.If the shift path exceeds a predefined value, this is detected by the engine electronics and interpreted as a shift request from the driver. The engine's drive torque is then briefly reduced or the ignition is interrupted, allowing shifting without using the clutch or even releasing the throttle. Immediately after the shift, the engine torque is increased again within fractions of a second.

[0003] It should be expressly noted at this point that a transmission shift assist device within the meaning of the invention is not to be understood as a synchronization device for a transmission; a transmission shift assist device merely serves to detect a shifting request of the driver via a sensor device and to transmit a corresponding electronic signal to an engine control unit or engine electronics.

[0004] A disadvantage of known gearbox shift assist devices is that the compression spring(s) must be relatively stiff to enable precise neutral engagement. This is because, when engaging neutral, the gearbox shift assist device should not engage but rather move as a whole, i.e., without any relative movement between the piston and the housing. Therefore, the compression springs in the gearbox shift assist device must have a sufficiently high spring rate so that, from a neutral position, the force required to compress the compression springs is greater than the force required in the gearbox to engage neutral. As a consequence, the force the driver must exert against the compression springs when further compressing them (as is the case with every gear change) increases even further, although this is not necessary for the actual shifting process. Many drivers perceive this level of force as stiff and uncomfortable.

[0005] It is therefore an object of the invention to provide a transmission shifting assistance device or a shifting device for a motorcycle that avoids the aforementioned disadvantages.

[0006] According to the invention, a locking device, separate from the compression spring(s), is provided in a transmission shift assist device of the type mentioned above. This locking device secures the piston in a neutral position relative to the housing below a predetermined unlocking force exerted on the piston or the housing. Until the predetermined unlocking force is exceeded, the locking device prevents relative movement between the piston and the housing, thus preventing the transmission shift assist device from activating. Below the predetermined unlocking force, the transmission shift assist device as a whole is moved, allowing neutral to be engaged. To shift gears, the driver increases the force applied. Upon exceeding the predetermined force threshold, the locking device releases, the shift assist device is actuated, and the gear change is performed.Since the locking device in the transmission shift assist device according to the invention ensures reliable neutral engagement, the compression springs, or the compression spring in the transmission shift assist device itself, can be made significantly softer. The transmission shift assist device according to the invention thus provides increased driving comfort, as the driver experiences significantly less effort when shifting gears than before, without compromising precise neutral engagement.

[0007] According to a preferred embodiment, two compression springs are provided, arranged on both sides of the piston in the housing, particularly wherein the piston is located approximately centrally in the housing in its neutral position in the axial direction. The two compression springs can have different spring characteristics, which can be advantageous in practice, especially since studies have shown that pulling a foot shift lever upwards is considerably more sensitive than pushing a foot shift lever downwards. Therefore, it is advantageous if the spring characteristic is softer in the first shifting direction (i.e., upwards) than in the second shifting direction (i.e., downwards).

[0008] Alternatively, it is of course also possible to use only a single compression spring, which results in a particularly small installation space requirement.

[0009] A particularly reliable yet simple and therefore cost-effective design can be achieved if the locking device has a locking spring and a locking element actuated by the locking spring.

[0010] Preferably, the locking spring is a coil spring, which is easy and inexpensive to manufacture.

[0011] Preferably, the locking element is a ball which, due to its geometry, allows for easy release when appropriate force is applied.

[0012] In a preferred embodiment, the piston has a recess in which the locking spring and the locking element are arranged, the locking spring tending to push the locking element out of the recess into a housing-fixed locking recess. This is easy to implement in manufacturing.

[0013] Alternatively, the locking spring and the locking element can be arranged in a recess in the housing, in which case the locking spring presses the locking element into a recess on the piston.

[0014] In particular, one longitudinal axis of the recess extends perpendicular to the piston's direction of movement. This allows unlocking with the same force in both directions of piston movement relative to the housing.

[0015] In order to securely fix the piston in the housing below the specified unlocking force, the locking element protrudes at least partially from the recess in the neutral position and extends into the locking recess to form a positive fit.

[0016] Preferably, a circumferential wall of the housing has the locking recess into which the locking element engages at least partially in the neutral position.

[0017] According to a preferred embodiment, the at least one compression spring and the locking spring, as well as the geometry of the locking element and the locking recess, are coordinated such that the axial displacement force required to move the locking element out of the locking recess is greater than the subsequent displacement force required to move the piston against the at least one compression spring. This ensures precise neutral engagement, resulting in significantly lower forces for the driver when shifting gears.

[0018] In a further development of the invention, a first part of a sensor arrangement is provided on the piston, which interacts with a second part provided on the housing, thereby enabling the detection of relative movement between the housing and the piston. In particular, this is a non-contact magnetic sensor. Of course, the sensor arrangement can also be arranged elsewhere, for example on a piston rod connected to the piston.

[0019] The transmission shift assist device according to the invention is used in particular in a shifting device for a motorcycle, with a shift lever that can be operated by foot in a first shifting direction or in a second shifting direction opposite to the first shifting direction, and which is coupled to a shift input of a motorcycle transmission via the transmission shift assist device, wherein the transmission shift assist device enables shifting with the clutch engaged. Such a shifting device ensures increased riding comfort, since the rider experiences significantly less effort when shifting gears than before, without having to sacrifice precise neutral finding.

[0020] Further features and advantages will become apparent from the following description of a preferred embodiment with reference to the accompanying drawing.

[0021] In this figure, the only one shows a sectional view of a gearbox shift assist device used in a shifting device for a motorcycle.

[0022] The figure shows a transmission shift assist device 10 (also referred to as a shift assist) according to the invention for a motorcycle shifting device. The transmission shift assist device 10 has a piston 12 connected to a piston rod 14. The piston 12 is slidably arranged in a housing 16, which is fixedly connected to a housing rod 18. The figure shows the piston 12 in its neutral position, in which it is arranged approximately centrally in the housing 16 in the axial direction A.

[0023] The second end of the piston rod 14, not shown in the figure, serves to connect the piston 12 to the motorcycle's gearbox, while the second end of the housing rod 18, also not shown, serves to connect the housing 16 to the motorcycle's foot shift lever. Alternatively, it is of course also possible to connect the piston 12 to the shift lever and the housing 16 to the motorcycle's gearbox input. The gearbox shift assist device 10 is thus arranged as a shift force transmission device between the shift lever and the motorcycle's gearbox input.

[0024] On the side of the piston 12 facing the piston rod 14, a first compression spring 20 is arranged in the housing 16, which is supported on the left side of the piston 12, in particular on a guide element 22 provided there. The other end of the compression spring 20 is supported on a housing cover 24. On the side of the piston 12 facing the housing rod 18, a second compression spring 26 is arranged in the housing 16, which is also supported on a guide element 28 provided on the piston 12 and on the other side on a housing cover 30.

[0025] A first part 32 of a sensor arrangement 34 is provided on the piston 12, which interacts with a second part 36 provided on the housing 16 and is connected to motor electronics via a connecting cable (not shown). In particular, it is a non-contact magnetic sensor, such as a Hall sensor.

[0026] Furthermore, a locking device 38 is provided, which is designed separately from the compression springs 20, 26. The locking device 38 has a locking spring 40 designed as a coil spring and a locking element 42 in the form of a ball acted upon by the locking spring 40.

[0027] Both the locking spring 40 and the locking element 42 are arranged in a cylindrical recess 44 of the piston 12, the longitudinal axis L of which extends perpendicular to the displacement direction of the piston 12, which corresponds to the axial direction A. The locking spring 40 partially pushes the locking element 42 out of the recess 44 into an approximately hemispherical locking recess 46, which is formed in a circumferential wall 48 of the housing 16.

[0028] In the neutral position shown in the figure, the locking element 42 engages at least partially in or extends into the locking recess 46 to form a positive fit. This secures the piston 12 in the neutral position relative to the housing 16, unless a predetermined unlocking force in axial direction A is exerted on the piston 12 or the housing 16 that is sufficient to release the locking device 38.

[0029] Here, the compression springs 20, 26 and the locking spring 40, as well as the geometry of the locking element 42 and that of the locking recess 46 in the circumferential wall 48 of the housing 16, are coordinated such that the axial displacement force required to move the locking element 42 out of the locking recess 46 is greater than the subsequent displacement force required to move the piston 12 against the compression spring 20 or 26.

[0030] If neutral is to be engaged on the motorcycle, the rider exerts a force on the foot shift lever that is less than the specified unlocking force of the locking device 38, so that the shift assist device 10 moves as a whole and neutral is engaged in the transmission.

[0031] If, on the other hand, the driver wishes to shift into a higher gear, he pulls the foot shift lever upwards with a correspondingly greater force (this is forced by the engine torque, which blocks the shift drum, the gear shift lever and ultimately the housing rod 18 until the engine control reduces the torque), so that the axial, leftward displacement force exerted on the housing 16 (or the piston 12) via the housing rod 18 pushes the locking element 42 completely out of the locking recess 46 and into the recess 44 of the piston 12 against the preload of the locking spring 40, thus enabling the relative movement between the piston 12 and the housing 16.

[0032] During upshifting, the housing 16 of the shift assist device 10 is also subjected to pressure by the pressure applied via the housing rod 18, which causes the compression spring 26 to compress. The piston rod 14 moves into the housing and takes the piston 12 with it to the right, which is registered by the housing-mounted sensor assembly 34 and transmitted to the engine electronics. This recognizes an upshift request from the driver and briefly reduces the engine's drive torque, which then enables (up)shifting without clutch engagement. The spring 26 then returns the device to its neutral position.

[0033] In the reverse shifting direction, the shift assist device 10 functions analogously. If the driver wishes to downshift, he pushes the foot shift lever downwards from the neutral position, again with a force sufficient to release the locking device 38 by moving the locking element 42 against the locking spring 40 far enough into the recess 44 of the piston 12 that the piston 12 is no longer fixed relative to the housing 16. The movements of the other parts can be described as follows.

[0034] The rod 14, moving to the left, carries the guide element 22 and the piston 12 with it to the left, causing the compression spring 20 to compress. The compression spring 26 extends to the left and, via the guide element 28, pushes the piston 12 and the part 32 to the left.

[0035] The relative displacement between piston 12 and housing 16 is interpreted by the engine electronics as a shift request from the driver to downshift to a lower gear. The engine's drive torque is again briefly reduced, thus enabling downshifting without clutch engagement. Springs 20 and 26 then return the cylinder to neutral.

[0036] Since the compression springs 20, 26 have a significantly lower spring constant compared to the compression springs of shift assist devices known from the prior art, shifting is considerably more comfortable for the driver with the shift assist device 10 according to the invention. Precise neutral engagement is nevertheless ensured by the locking device 38.

[0037] In a further training course, it may be provided that the two compression springs 20, 26 have different spring characteristics.

Claims

[1] Gear shift assist device, in particular for a motorcycle, comprising a housing (16), a piston (12) arranged in the housing (16) and at least one compression spring (20, 26) provided in the housing (16), wherein the piston (12) is displaceable relative to the housing (16) under compression of at least the compression spring (20, 26), characterized by , that a locking device (38) designed separately from the compression spring or compression springs (20, 26) is provided, which secures the piston (12) in a neutral position relative to the housing (16) below a predetermined unlocking force exerted on the piston (12) or the housing (16). [2] Gear shift assist device according to claim 1, characterized by , that two compression springs (20, 26) are provided which are arranged on both sides of the piston (12) in the housing (16), in particular wherein the piston (12) is arranged in its neutral position in the axial direction (A) approximately in the middle of the housing (16). [3] Gear shift assist device according to claim 1 or 2, characterized by , that the locking device (38) has a locking spring (40) and a locking element (42) acted upon by the locking spring (40). [4] Gear shift assist device according to claim 3, characterized by , that the locking spring (40) is a coil spring. [5] Gear shift assist device according to claim 3 or 4, characterized by , that the locking element (42) is a ball. [6] Gear shift assist device according to one of claims 3 to 5, characterized by , that the piston (12) has a recess (44) in which the locking spring (40) and the locking element (42) are arranged, wherein the locking spring (40) tends to push the locking element (42) out of the recess (44) into a housing-fixed locking recess (46). [7] Gear shift assist device according to claim 6, characterized by , that a longitudinal axis (L) of the recess (44) extends perpendicular to the direction of displacement of the piston (12). [8] Gear shift assist device according to claim 6 or 7, characterized by , that the locking element (42) in the neutral position extends at least partially out of the recess (44) and into the locking recess (46) to form a positive fit. [9] Gear shift assist device according to one of claims 6 to 8, characterized by , that a circumferential wall (48) of the housing (16) has the locking recess (46) into which the locking element (42) engages at least partially in the neutral position. [10] Gear shift assist device according to one of claims 6 to 9, characterized by, that the at least one compression spring (20, 26) and the locking spring (40) as well as the geometry of the locking element (42) and that of the locking recess (46) are coordinated such that the axial displacement force for moving the locking element (42) out of the locking recess (46) is greater than the subsequent displacement force to be applied for moving the piston (12) against the at least one compression spring (20, 26). [11] Gear shift assist device according to one of the preceding claims, characterized by , that a first part (32) of a sensor arrangement (34) is provided on the piston (12), which interacts with a second part (36) provided on the housing (16), thereby enabling the detection of a relative movement between the housing (16) and the piston (12). [12] Shifting device for a motorcycle, comprising a shift lever which can be operated by foot in a first shifting direction or in a second shifting direction opposite to the first shifting direction, which is coupled to a shift input of a motorcycle transmission via a transmission shift assist device (10) according to one of claims 1 to 11, wherein the transmission shift assist device (10) enables shifting with the clutch closed.

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