Transmission mechanism and moved machinery including the same

Abstract

To develop a transmission mechanism which enables reduction of an impact during shifting operation by a dog clutch and a moved machinery including the transmission mechanism.SOLUTION: In a transmission mechanism 14 of the invention, sets of gears, which make pairs having different gear ratios, are provided at an input side shaft 22 and an output side shaft 23 in a constantly engaged state. One of the gear rotates, fixed to the shaft 23 and the other gear is supported so as to be rotatable freely relative to the shaft 22. The shaft 22 is provided with a dog clutch 29 which can slide in an axial direction in a state that the shaft 22 is rotatable fixed to the shaft 22 by helical spline engagement. The dog clutch 29 is engaged with the gear which freely rotates to cause the gear to rotate, fixed to the shaft 22. The dog clutch 29 selects the set of the gears making the pair to switch a rotation ratio of the output side shaft 23 according to a needed gear ratio.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a constant mesh type transmission mechanism, and in particular to a transmission mechanism that enables smooth meshing (engagement) between the dog clutch and the gear that acts when changing gears, and to a driven member equipped with the same. [Background technology]

[0002] 2. Description of the Related Art In vehicles such as automobiles and motorcycles that are driven by internal combustion engines, drive to the wheels is achieved through a multi-stage or infinitely variable transmission due to the output characteristics of the engine. On the other hand, due to recent demands for environmental friendliness, so-called electric vehicles (hereinafter referred to as electric vehicles) driven by electric motors have become increasingly popular. In such electric vehicles, because the motors generate a large torque at start-up due to their output characteristics, in many cases no mechanical transmission is interposed between the motor and the wheels.

[0003] However, in order to effectively utilize the output characteristics of the motor, it is desirable to use a transmission to obtain an appropriate gear ratio as the speed increases. The gear transmission used for this purpose adopts a configuration in which a pair of gears that are always in mesh with each other are made to rotate freely on a shaft, while the other gear is made to rotate fixedly on the shaft, and a dog clutch that is rotated fixedly on the shaft is engaged with the freely rotating gear, thereby creating a driving meshing state of the pair of gears. In such a configuration, when the dog protrusion of the dog clutch moves on the shaft and engages with the dog receiving recess on the gear side, a certain amount of impact is unavoidable, which may result in adverse effects on the related drive train. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-98459 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention was made taking into consideration the above-mentioned background, and its technical objective was to develop a transmission mechanism capable of reducing the shock that occurs when shifting using a dog clutch, as well as a driven member equipped with the same. [Means for solving the problem]

[0006] That is, the speed change mechanism according to claim 1 is as follows: At least two or more pairs of gears with different gear ratios are provided in a constant meshing state for an input shaft and an output shaft arranged in parallel, one of the meshed gears rotates fixedly relative to the shaft, while the other gear is supported in a freely rotating state relative to the shaft, and a dog clutch that is fixed to the freely rotating gear by spline engagement and can slide in the axial direction of the shaft is provided on the shaft supporting the freely rotating gear, and this dog clutch engages with the freely rotating gear to fix the freely rotating gear to the shaft, and the dog clutch switches the rotation ratio of the output shaft according to the required gear ratio by selecting one of the paired gear sets, The spline engagement between the dog clutch and the shaft in this sliding range is characterized by being a helical spline engagement.

[0007] The speed change mechanism described in claim 2 has, in addition to the requirements described in claim 1, The helical direction of the helical spline is set in a direction that causes the rotation of the dog clutch to lag for gears with a high gear ratio and to lead for gears with a low gear ratio.

[0008] The speed change mechanism described in claim 3 has, in addition to the requirements described in claim 2, There are two sets of gears provided on the shaft, and these sets of gears are characterized in that a dog clutch is provided between the two sets of gears on the shaft that supports the gears in a free state, and by sliding this dog clutch in the axial direction of the shaft, one of the sets of gears can be fixed in rotation.

[0009] The speed change mechanism described in claim 4 has, in addition to the requirements described in claim 1 or 2, Either or both of the dog clutch and the gear are provided with a synchronizing mechanism that brings them into loose contact prior to engagement, thereby synchronizing the rotations of both.

[0010] The speed change mechanism described in claim 5 has, in addition to the requirements described in claim 1 or 2, This device is characterized in that a rotation sensor is provided on the input side shaft or on the input system rotating member upstream of this, and when the detection value of this rotation sensor indicates that the dog clutch is in an optimum engagement state, it either notifies the user that this engagement is in an optimum engagement state or engages the dog clutch with the gear, or both.

[0011] The speed change mechanism described in claim 6 has, in addition to the requirements of claim 1 or 2, The power unit inputted to the input side shaft is characterized in that it is an electric motor.

[0012] The driven member according to claim 7 is The driven member is any one of a railway vehicle, an automobile, a motorcycle, a motor-assisted bicycle, a wind power generator, an outboard motor, and a winch device, This driven member is characterized in that it comprises the speed change mechanism according to claim 1 or 2. The above problems are solved by the means described in each claim. Effect of the Invention

[0013] First, according to the invention described in claim 1, the dog clutch is helical spline connected to the shaft. Therefore, when the dog clutch engages (fastens) with the gear provided on the shaft, it does not simply slide in the axial direction, but also undergoes rotational movement relative to the shaft. When engaging with the gear, speed matching in the rotational direction occurs, and the impact associated with switching can be mitigated or eliminated.

[0014] According to the invention as set forth in claim 2 or 3, smooth engagement is achieved under a tendency to increase speed during downshift switching, and smooth engagement is achieved under a tendency to decrease speed during upshift switching.

[0015] According to the invention described in claim 4, the difference in rotation between the dog clutch and the gear can be reduced or eliminated before the dog clutch completely engages with the gear. That is, from the time when the dog clutch starts to engage, the dog clutch gradually comes into contact with the gear, so that the rotation of the dog clutch is gradually transmitted to the gear, and the rotation of the gear can be gradually synchronized with the dog clutch, thereby suppressing a sudden impact accompanying engagement.

[0016] Furthermore, according to the invention described in claim 5, the dog clutch is engaged (fastened) with the gear after the rotation speed of the input shaft on which the dog clutch is provided reaches an optimized state (engagement optimized state), thereby further reducing the sudden impact associated with the engagement of the dog clutch.

[0017] According to the invention as set forth in claim 6, when the dog clutch is engaged with the gear side, the occurrence of impact can be minimized, and the output characteristics of the electric motor can be effectively utilized.

[0018] Furthermore, according to the invention described in claim 7, it is possible to obtain various driven devices to which the speed change mechanism according to the present invention is applied, specifically, railway cars, automobiles, motorcycles, motor-assisted bicycles, wind power generators, outboard motors, winch devices, etc. [Brief description of the drawings]

[0019] [Figure 1]1 is a schematic diagram showing a vehicle as a driven member to which a speed change mechanism of the present invention is applied; [Diagram 2] FIG. 2 is a schematic diagram showing an outboard motor as a driven member according to the first embodiment. [Diagram 3] FIG. 2 is a schematic diagram showing a motorcycle as a driven device according to the first embodiment. [Figure 4] FIG. 2 is a schematic diagram showing a wind power generator as a driven device according to the first embodiment. [Diagram 5] FIG. 1 is a perspective view showing an example of a speed change mechanism of the present invention. [Figure 6] FIG. 13 is a plan view (a) of the same as above, and a plan cross-sectional view (b) showing an enlarged example of a configuration in which a wave plate is provided between a dog slide fork and two fork fixing members arranged to sandwich it. [Figure 7] FIG. [Figure 8] FIG. 4 is a front view of the dog clutch as viewed from the axial direction of the shaft. [Figure 9] FIG. [Figure 10] 10 is an explanatory view showing a configuration example in which an inner peripheral side of a gear connecting protrusion is formed into an inclined notch shape in the dog clutch shown in FIG. 9. FIG. [Figure 11] 1 is a front cross-sectional view of a helical spline shaft as viewed in the axial direction of the shaft. [Figure 12] FIG. [Figure 13] FIG. 4 is a projection view of an input side small gear as viewed from the axial direction of a shaft. [Figure 14] 1 is a cross-sectional view showing an input side small gear (or large gear) in which a dog-receiving recess (fitting groove) is formed in an overall inclined shape (tapered or conical notch). [Figure 15] FIG. 4 is a cross-sectional view showing a dog receiving recess of the input side small gear. [Figure 16] FIG. 4 is a cross-sectional view showing a dog receiving recess of the input side large gear. [Figure 17]FIG. 17(a) is a cross-sectional view illustrating a combination of the input side small gear and input side large gear shown in FIGS. 13 to 15, the dog clutch shown in FIG. 9, and the helical spline shaft shown in FIG. 12, and FIG. 17(b) is an explanatory diagram showing how the rotation of the dog clutch tends to lag (slip loss) when the dog clutch is engaged (fastened) with the input side large gear. [Figure 18] 1 is a cross-sectional view showing an input side small gear having a synchro boss formed to extend the shaft hole and a synchro ring portion provided on the outer periphery of the synchro boss. [Figure 19] 1 is a cross-sectional view showing an input side large gear having a synchro boss formed to extend the shaft hole and a synchro ring portion provided on the outer periphery of the synchro boss. [Figure 20] 19 is a cross-sectional view of a combination of the input side small gear shown in FIG. 18, the input side large gear shown in FIG. 19, the dog clutch shown in FIG. 10, and the helical spline shaft shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present invention is as shown in the following examples, but it is possible to make appropriate modifications to these examples within the scope of the technical concept of the present invention. EXAMPLES

[0021] When the speed change mechanism 14 of the present invention is constructed as an actual machine, it is housed, for example, in an oil bath in a gear box provided with a predetermined strength, etc. However, in the following embodiment, some parts are illustrated symbolically so that the basic structure of a so-called demonstration machine can be understood. The speed change mechanism 14 shown in this embodiment has components arranged on a frame F, as shown in Figs. 5 to 7 as an example, and the frame F is configured in a substantially rectangular frame shape in a plan view as an example. In the transmission mechanism 14, an input side shaft 22 and an output side shaft 23 are rotatably and parallelly attached to the frame F via a shaft fixing device 32. An input side driving member 11 is connected to one end of the input side shaft 22. One example of the input side driving member 11 is an electric motor, and the rotation of the electric motor is transmitted to the input side shaft 22 in a reduced speed state via a first reduction gear 21a and a second reduction gear 21b as shown in FIG.

[0022] 5 and 6, the input side small gear 24 and large gear 26 are attached to the input side shaft 22 via a bearing B (see FIG. 17) so that they are free to rotate relative to the shaft 22. When gear members, including the output side large gear 25 and output side small gear 27 described below, are collectively or commonly referred to as "gears", they are simply referred to as "gears", and the term "gears" is also used in the claims. A dog clutch 29 is further provided between the small gear 24 and the large gear 26 on the input side shaft 22 so as to be slidable in the axial direction of the shaft 22. The structures of the small gear 24, the large gear 26, the dog clutch 29 and the shaft 22 which supports them will be described below.

[0023] First, as described above, the small gear 24 and the large gear 26 are rotatably supported on the shaft 22 via the bearing B, and are fixed to the shaft 22 in the rotational direction by fastening the dog clutch 29. For this reason, as shown in Figures 13 to 15, the small gear 24 is provided with, for example, four dog receiving recesses 24R each having an elongated hole shape in the circumferential direction, and similarly, the large gear 26 is provided with, for example, four dog receiving recesses 26R each having an elongated hole shape in the circumferential direction (see Figure 16).

[0024] Next, the dog clutch 29 and the spline structure provided on the shaft 22 supporting it will be described. Both are characteristic configurations of the present invention, and the spline structure is configured as a helical spline (this is referred to as a helical spline shaft 28). That is, the input side shaft 22 is configured as a helical spline shaft 28 on the outer periphery side between the small gear 24 and the large gear 26, and four helical spline ridges 28a are formed, and spline grooves 28b that are relatively groove-like are formed between the spline ridges 28a (see Figs. 11 and 12). With such a configuration of the helical spline shaft 28, the dog clutch 29 is formed in a center hole with four ridge rotational sliding protrusions 37, as shown in Fig. 8, for example, and thus a rotational sliding recessed groove portion 371 that is relatively recessed is formed, and these are formed in a helical shape with the same lead angle so that they can be inserted into the helical spline shaft 28. Due to this spline connection, the dog clutch 29 rotates in conjunction with the rotation of the input shaft 22 .

[0025] Further, the dog clutch 29 has gear connecting projections 36 on both side surfaces, for example, four on each side, totalling eight on both sides, as shown in Figs. These gear connecting protrusions 36 are formed to have an approximate cylindrical shape, and when the dog clutch 29 slides toward either the small gear 24 or the large gear 26, they mesh with each other so as to fit within the dog receiving recesses 24R, 26R of each gear 24, 26 (see Figure 17), causing either of the gears 24, 26 to rotate together with the input shaft 22. The movement of the dog clutch 29 when it is coupled to the gears 24 and 26 is guided by the helical spline shaft 28, and speed matching occurs in the rotational direction, which will be described later.

[0026] Further, the dog clutch 29 has a fork receiving groove 29a on its outer periphery for receiving a shifting operation therefor. The following describes the shift structure of the dog clutch 29. The main component of the shift structure is the dog slide fork 30, which, as shown in Fig. 8 above as an example, is configured as a dog shift end 30a formed in a bifurcated C-shape forming an arc-shaped fork at the tip end (free end) side acting on the dog clutch 29, and the base end 30b side is supported by a fork sliding shaft 35. The fork sliding shaft 35 is a screw shaft supported by the frame F, and is driven by the rotation of the shift motor which is the gear change control device 13, and the axial movement (sliding) of the dog slide fork 30 is achieved by screwing into a female thread provided at the base end portion 30b of the dog slide fork 30. Note that reference numerals 34a and 34b in Fig. 6(b) are fork fixing members which hold the dog slide fork 30 from both sides via pins P to fix the dog slide fork 30.

[0027] The above are the members related to the input-side shaft 22, and next we will explain the output-side shaft 23. The output-side shaft 23 is a so-called countershaft to the input-side shaft 22, and is equipped with the output-side acting member 12 at one end of the shaft. Specifically, the output-side acting member 12 is a connection part corresponding to the target mechanism in which the speed change mechanism 14 is provided, such as a gear, sprocket, pulley, or a shaft directly connected to the target mechanism. Furthermore, a large gear 25 and a small gear 27 are provided on the output side shaft 23 in a rotationally fixed state relative to the shaft 23. Here, the output side large gear 25 is a gear that meshes with the small gear 24 of the input side shaft 22, and the output side small gear 27 is a gear that meshes with the large gear 26 of the input side shaft 22. Therefore, when the dog clutch 29 is engaged with the small gear 24 on the input side shaft 22, the rotation of the input side shaft 22 is transmitted to the output side shaft 23 via the input side small gear 24 and the output side large gear 25. This state is a state in which the combination (gear combination) of the input side small gear 24 and the output side large gear 25 is in a rotationally fixed state. Furthermore, when the dog clutch 29 is engaged with the large gear 26 on the input side shaft 22, the rotation of the input side shaft 22 is transmitted to the output side shaft 23 via the input side large gear 26 and the output side small gear 27. In this state, the combination (gear combination) of the input side large gear 26 and the output side small gear 27 is fixed in rotation.

[0028] An example of the configuration of the speed change mechanism 14 of the present invention has been described above, and operates as follows to perform a smooth shift operation. <Starting state> In the case of an electric motor, driving can be started smoothly by supplying power, but for convenience, the dog clutch 29 is set to a neutral position, that is, a state in which it is not engaged with either the small gear 24 or the large gear 26. Even if the input side shaft 22 receives driving force and rotates in this non-engaged state, the small gear 24 and the large gear 26 are not fixed to the shaft 22, so the rotation is not transmitted to the output side shaft 23.

[0029] <Rotation of the input shaft and dog clutch> On the other hand, when the input side shaft 22 receives rotational drive from the input side electric motor (driving member 11), the shaft 22 rotates and the dog clutch 29 spline-fitted with the helical spline shaft 28 also rotates (rotates together).

[0030] <Engagement of dog clutch> In this state, the shift motor or the like serving as the gear change control device 13 is driven to move the dog slide fork 30, for example, toward the small gear 24 side that receives the dog. Since the dog clutch 29 is engaged with the helical spline shaft 28, as shown in Figure 6(a) for example, speed matching occurs in the rotation direction of the input shaft 22, and smooth dog fastening is achieved (see Figure 17(a)). Of course, when an electric motor is used as the input side prime mover, the small gear 24 and the dog clutch 29 can be engaged in advance. The smooth engagement (connection) of the dog clutch 29 by speed matching described above is effective when the vehicle is driven at a high gear ratio, that is, when the dog clutch 29 is engaged on the low speed side, i.e., the small gear 24 side, for so-called downshifting, when the vehicle is driven at a high gear ratio. More specifically, even when the large gear 26 on the input side and the small gear 27 on the output side are connected, the gear train is of a constant mesh type, so that even if the small gear 24 on the input side shaft 22 rotates freely, it is rotating at an increased speed due to the rotation of the large gear 25 on the output side fixed to the shaft 23 on the output side. At this time, the dog clutch 29 meshes with the small gear 24 under the tendency to increase in speed, thereby achieving smooth engagement.

[0031] <From low gear to high gear> This operation is to change from the downshift state described above to an upshift state, and in this case, the large gear 26 on the input side rotates at a lower rotation speed than the small gear 24. That is, since the transmission mechanism 14 of the present invention has a combination structure of constantly meshing gears, in the downshift state, the rotation on the output side is decelerated (low rotation), and this decelerated rotation is transmitted at a low rotation speed from the large gear 26 on the input side to the small gear 27 on the output side. As a result, when the dog clutch 29 meshes with the large gear 26, due to the helical shape of the helical spline shaft 28, the dog clutch 29 meshes under a rotation that matches the movement of the rotating small gear 24 at a speed slower than the input shaft rotation by speed matching in the deceleration direction. In other words, when the dog clutch 29 engaged with the small gear 24 on the input side is engaged with the large gear 26 on the input side, as shown in FIG. 17(b) as an example, the dog clutch 29 moves along the spiral of the helical spline shaft 28, so that the dog clutch 29 moves in the axial direction of the shaft 22 (linear movement towards the large gear 26) and also moves in a direction perpendicular to the axial direction of the shaft 22, and this vertical movement becomes a rotational movement in the opposite direction to the rotational direction of the shaft 22. In other words, in this case, the dog clutch 29 is engaged with the large gear 26 so that the rotation of the dog clutch 29 tends to be delayed. Note that this tendency to be delayed is due to the vertical component of the rotational movement when it moves (slips) along the spiral of the helical spline shaft 28, and is, so to speak, a "slip loss."

[0032] Other Examples The present invention is based on the above-described embodiment as one basic technical concept, but the following modifications can be considered. Example of smooth meshing <Synchronizer> First, when the dog clutch 29 is connected to the input side small gear 24 or the input side large gear 26, it is possible to provide a synchronizing mechanism for synchronizing the rotational speeds. As shown in Figures 10, 18, 19 and 20, the synchronizing mechanism is provided at the engagement portion between the dog clutch 29 and the input side small gear 24 or large gear 26 that meshes with it. That is, a synchronizing boss 39b is formed to extend each of the shaft holes 24h and 26h of the small gear 24 or large gear 26, and a synchronizing ring portion 39 is formed on the outer periphery thereof (see Figures 18 and 19). Also, the small gear 24 and large gear 26 are formed with dog receiving recesses 24R and 26R that are inclined (tapered or conical notches), i.e., expand in diameter toward the dog clutch 29, so that the gear connecting protrusion 36 of the dog clutch 29 comes into loose contact with the synchronizing ring portion 39 (see Figure 14), thereby reducing or eliminating the difference in rotation between the dog clutch 29 and each gear 24 and 26 before the dog clutch 29 meshes with each gear 24 and 26. That is, from the point at which dog clutch 29 begins to engage, dog clutch 29 gradually comes into contact with each of gears 24, 26, and the engaging frictional force between them gradually increases. As a result, the rotation of dog clutch 29 is gradually transmitted to each of gears 24, 26, and each of gears 24, 26 is synchronized with the rotation of dog clutch 29 while suppressing sudden shocks.

[0033] <Chamfer mechanism> Although not shown, it is preferable to form a so-called chamfer between the gear connecting projection 36 of the dog clutch 29 and each of the gears 24, 26, which is a mechanism for facilitating meshing of the tooth surfaces of the gears with each other, in order to facilitate smooth meshing between the gear connecting projection 36 of the dog clutch 29 and each of the gears 24, 26. This chamfer is also included in the synchronizing mechanism in the claims.

[0034] <Optimization of dog clutch engagement timing (optimized engagement state)> Furthermore, by optimizing the operation timing of the dog slide fork 30, it is possible to set a rotation speed suitable for the shift operation so that the engagement of the dog clutch 29 with the gears 24 and 26 can be performed smoothly. That is, as an example, as shown in Fig. 6(a), a rotation sensor RC is provided on the input shaft 22, and the output of this sensor is input to the gear change control device 13 so that the engagement operation can be performed at an appropriate timing (rotation speed), which is referred to as an engagement optimization state in this specification. Incidentally, as the rotation sensor RC, for example, a gear-shaped protrusion can be provided on the input shaft 22, a proximity sensor can be used to output a pulse signal, and rotation speed data can be obtained by counting the pulses per unit time. In addition, when the engagement timing is optimized, an indicator such as a pilot lamp or a buzzer can be displayed. Of course, either the indicator display notifying the optimized state or the engagement operation in the optimized state may be performed independently. The rotation sensor RC does not necessarily have to be provided on the shaft 22 on the input side, but can also be provided on an input system rotating member upstream of the shaft 22.

[0035] <Smooth operation of dog slide fork> Furthermore, there is an embodiment which not only facilitates the meshing between the dog clutch 29 and the gears 24 and 26 which mesh with it, but also facilitates the operation of the dog slide fork 30 for moving the dog clutch 29. That is, for example, as shown in Fig. 6(b), it is possible to provide a buffer structure on the fork sliding shaft 35 which supports the base end 30b of the dog slide fork 30. Specifically, a buffer wave plate WP is interposed between the base end 30b of the fork sliding shaft 35 and the fork fixing members 34a and 34b. As for the shift mechanism of the dog slide fork 30, in addition to the mechanisms already mentioned, any known configuration may be used as appropriate, such as a shift drum that is often used in the transmission mechanisms of motorcycles. In the basic embodiment described above, the fork sliding shaft 35 formed of a screw shaft is used when sliding the dog sliding fork 30 (i.e., the dog clutch 29) along the shaft 22. However, when sliding the dog clutch 29, it is also possible to form a helical groove on the outer periphery of the dog clutch 29, provide a new multiple-start screw shaft that meshes with the groove, and rotate the multiple-start screw shaft to slide the dog clutch 29 toward each of the gears 24 and 26.

[0036] <<Embodiment regarding gear arrangement>> In addition, in the basic embodiment described above, the small gear 24 and large gear 26 supported on the input side shaft 22 are set in a free state, while the large gear 25 and small gear 27 provided on the output side shaft 23 are fixed to the shaft 23, and a dog clutch 29 is engaged with each of the gears 24 and 26 on the shaft 22 in the free state to rotate and fix them, so that the rotation of the shaft 22 is transmitted to one of the gears 25 and 27. However, whether the gears on the input and output shafts 22 and 23 are held freely or fixedly can be determined appropriately. For example, the gears 25 and 27 supported on the output shaft 23 may be supported freely. Furthermore, for example, the small gear 24 on the input shaft 22 may be made free, while the small gear 27 on the output shaft 23 may be made free, and separate dog clutches 29 may be applied to each. Furthermore, the gear train described above is a two-stage high / low speed change, but it is also possible to provide a multi-stage speed change with more than two stages, such as a four-stage speed change by providing four sets of gears with different gear ratios.

[0037] <Examples of applied equipment> To explain application fields of such a speed change mechanism, examples of the driven machine in the application field include vehicles, aircraft, wind power generators (see FIG. 4), outboard motors (see FIG. 2), and even winch devices used in cargo handling equipment such as elevators and lifts, fishing equipment, etc. Reference numeral 18 in FIG. 4 denotes a generator. Examples of vehicles include railway cars such as electric trains, automobiles (see FIG. 1), motorcycles (see FIG. 3), and power-assisted bicycles. Reference numeral 15 in the figure denotes a vehicle tire, reference numeral 16 in the figure denotes the screw of an outboard motor, reference numeral 17 in the figure denotes the blades of a wind power generator, and reference numeral 18 in the figure denotes a generator. [Explanation of symbols]

[0038] 11 Driving member 12 Output side acting member 13 Gear shift control device 14 Transmission mechanism 15 Tires 16 Screw 17 Blades 18. Generator 21a 1st reduction gear 21b 2nd reduction gear 22 Shaft (input side) 23 Shaft (output side) 24 Small gear (input side) 24h shaft hole 24R Dog receiving recess 25 Large gear (output side) 26 Large gear (input side) 26h shaft hole 26R Dog receiving recess 27 Small gear (output side) 28 Helical spline shaft 28a Spline ridge 28b spline groove 29 Dog clutch 29a Fork receiving groove 30 Dog slide fork 30a Dog shift end 30b Proximal end 32 Shaft fixing device 34a Fork fixing parts 34b Fork fixing parts 35 Fork sliding shaft 36 Gear connection protrusion 37 Rotating and sliding protrusion 371 Concave groove for rotational sliding 39 Synchro Ring Section 39b Synchro Boss B Bearing F Frame P-pin WP Wave Plate

Claims

1. At least two or more pairs of gears with different gear ratios are provided in a constant meshing state for an input shaft and an output shaft arranged in parallel, one of the meshed gears rotates fixedly relative to the shaft, while the other gear is supported in a freely rotating state relative to the shaft, and a dog clutch that is fixed to the freely rotating gear by spline engagement and can slide in the axial direction of the shaft is provided on the shaft supporting the freely rotating gear, and this dog clutch engages with the freely rotating gear to fix the freely rotating gear to the shaft, and the dog clutch switches the rotation ratio of the output shaft according to the required gear ratio by selecting one of the paired gear sets, A speed change mechanism characterized in that the spline engagement between the dog clutch and the shaft in this sliding range is helical spline engagement.

2. 2. The transmission mechanism according to claim 1, wherein a spiral direction of the helical spline is set in a direction such that rotation of the dog clutch tends to lag for gears having a high gear ratio and tends to advance for gears having a low gear ratio.

3. 3. The transmission mechanism according to claim 2, wherein the number of gear sets provided on the shaft is two, and a dog clutch is provided between the two gear sets on a shaft that supports the gears in a free state, and the dog clutch is slid in the axial direction of the shaft to fix the rotation of one of the gear sets.

4. 3. The speed change mechanism according to claim 1, further comprising a synchronizing mechanism for synchronizing the rotation of the dog clutch and the gear by loosely contacting either one or both of them prior to engagement of the dog clutch and the gear.

5. 3. The transmission mechanism according to claim 1 or 2, characterized in that a rotation sensor is provided on the input side shaft or on an input system rotating member upstream of the input side shaft, and when the detection value of this rotation sensor indicates that the dog clutch is in an optimum engagement state, the transmission mechanism either notifies the user that this engagement optimization state is in effect or engages the dog clutch with the gear, or both.

6. 3. The transmission mechanism according to claim 1, wherein the power unit inputted to the input shaft is an electric motor.

7. The driven member is any one of a railway vehicle, an automobile, a motorcycle, a motor-assisted bicycle, a wind power generator, an outboard motor, and a winch device, The driven member is characterized in that it comprises the speed change mechanism according to claim 1 or 2.

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