Shift device of dog type transmission for vehicle

Abstract

To provide a shift device of a dog type transmission for a vehicle capable of reducing operation force and further obtaining shift speed.SOLUTION: In the shift device 74 of the transmission 26, since the connecting link 94 rotatably connected to the other end of the bell crank 90 and the shift member 88 absorbs the arc motion of the other end of the bell crank 90 and transmits the motion in the linear movement direction, which is the axial direction, to the shift member 88, the sliding of the shift member 88 becomes smooth, and the operating force for moving the shift member 88 is reduced. As a result, the shift device 74 of the transmission 26 capable of obtaining a higher shift speed is provided.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a shift device for a dog-type transmission for a vehicle, in which gears are changed in accordance with the rotation of a shift barrel. [Background technology]

[0002] A well-known vehicle transmission includes a rotating shaft, a plurality of speed change gears rotatably mounted on the rotating shaft, a plurality of switching mechanisms arranged adjacent to the speed change gears in the axial direction of the rotating shaft and switchable between an engaged state in which the speed change gears and the rotating shaft rotate integrally and a disengaged state in which they rotate relative to each other, and a shift mechanism that moves the switching mechanism in the axial direction of the rotating shaft. The shift mechanism includes a shift barrel shaft with a shift groove that determines the position of the switching mechanism, and a shift device that rotates the shift barrel shaft a predetermined angle using an actuator or an operating lever. The shift mechanism is moved in the axial direction of the rotating shaft in response to rotation of the shift barrel shaft, thereby shifting between a plurality of gear stages. Patent Document 1 discloses an example of such a vehicle transmission. Patent Document 1 discloses that the gear stage is changed by moving the switching mechanism using an annular shift groove formed in the shift barrel shaft.

[0003] This shift device includes a rack that engages with a pinion provided at the end of the shift barrel shaft, and an electric actuator that operates the rack. In addition, to prevent double meshing due to excessive rotation of the shift barrel shaft, the shift device also includes a stopper gear provided at the end of the shift barrel shaft and a double meshing prevention mechanism that includes a first stopper mechanism and a second stopper mechanism that engages with the stopper gear. As a result, the shift device has a large number of parts, making the structure complex and requiring a large installation space.

[0004] In response to this, Non-Patent Document 1 proposes a shift device that requires a compact installation space. In this shift device, multiple engagement pins are arranged at equal intervals in the circumferential direction on the shaft end of the shift barrel shaft, and a ratchet pawl having engagement recesses that receive two of the engagement pins and inclined portions on both sides of the engagement recesses is provided on the shift member in a state of being in pressure contact with the engagement pins, and an operating force is transmitted via a bell crank to reciprocate the shift member, thereby stopping the rotation of the shift barrel shaft at predetermined angle intervals. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-146775 [Non-patent literature]

[0006] [Non-Patent Document 1] "Helland FTR Manual Revised Edition," Hewland Engineering, published March 23, 2009, p. 43 (Fig. 21) Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the shift device described in Non-Patent Document 1, one end of the bell crank is fitted into a groove formed in the shift member, and the one end of the bell crank that moves in an arc inevitably slides against the groove of the shift member that moves linearly, which causes a problem in that the sliding resistance increases the operating force required for shifting and impairs the operating speed. Particularly in racing cars, a delay in operation speed increases the gap in driving force caused by gear changes, damaging the car's competitiveness.

[0008] The present invention has been made in light of the above circumstances, and its object is to provide a shift device for a dog-type transmission for a vehicle that requires less operating force and achieves faster shifting speeds. [Means for solving the problem]

[0009] The gist of the present invention is a shift device for a vehicle dog-type transmission including: (a) multiple types of gear pairs that mesh with each other and are provided on a first rotating shaft and a second rotating shaft that are parallel to each other; a shift fork that operates multiple meshing clutches between the gears of the gear pairs on the second rotating shaft side and the second rotating shaft; a shift barrel shaft that has multiple shift grooves that engage with the base ends of the shift forks, and that selectively establishes multiple gear positions at each predetermined rotation angle; and a shift member that linearly reciprocates multiple engagement pins that are arranged at equal circumferential intervals on the axial end of the shift barrel shaft, with a ratchet pawl having an engagement recess that receives two of the multiple engagement pins and inclined portions on both sides of the engagement recess, while pressing the engagement pins against the ratchet pawl; the shift device applies an operating force to one end of a bell crank and transmits the operating force from the other end to the shift member; and (b) a connecting link that is rotatably connected to the other end of the bell crank and the shift member, respectively. [Effects of the Invention]

[0010] According to the present invention, the connecting link absorbs the arcuate motion of the other end of the bell crank and transmits linear axial motion to the shift member, thereby allowing the shift member to slide smoothly, reducing the operating force required to move the shift member, and providing a shift device for a vehicle dog-type transmission that enables faster shifting.

[0011] Preferably, the connecting link and the shift member are connected to each other via a ball joint so as to be rotatable about the center of the ball joint. The ball joint includes a ball shaft having one end fastened to the connecting link and the other end formed into a spherical shape, and a ball bearing shaft having one end formed with a ball bearing portion for rotatably receiving the spherical portion and the other end rotatably connected to the other end of the bell crank, with one of the ball shaft and the ball bearing shaft functioning as the connecting link. In this case, the other end of the connecting link is connected to the shift member via the ball joint so as to be rotatable about the center of the ball joint. The ball joint has a large sliding contact area, so bending resistance is small even when a large operating force is momentarily applied, which has the advantage of enabling greater shifting speed.

[0012] Preferably, the ball joint comprises a ball shaft having a spherical portion at its end, and a ball bearing shaft having a ball bearing portion that accommodates the spherical portion of the ball shaft together with a lubricant so that the spherical portion can rotate. This allows the lubricant, such as grease, to smooth the sliding between the spherical portion and the ball bearing portion, thereby increasing the durability of the ball joint. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating a schematic configuration of a dog-type transmission for a vehicle to which the present invention is applied. [Figure 2] 3 is a diagram illustrating the arrangement of a main shaft, a counter shaft, a pair of drive shafts, and a shift device in the second axial direction of a dog-type transmission for a vehicle. FIG. [Figure 3] 3A and 3B are diagrams illustrating a gear shift operation mechanism of the shift device. [Figure 4] 10A and 10B are diagrams illustrating a gear shift operation mechanism of a shift device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0015] FIG. 1 is a schematic diagram illustrating the general configuration of a vehicle 10 to which the present invention is applied. The vehicle 10 is provided with a power transmission device 16 in a power transmission path between an engine 12 and a pair of drive wheels 14. The power transmission device 16 includes, in order from the engine 12 side, a clutch K1, a bevel gear pair 24, a transmission 26, and a differential gear 58. Of the power transmission device 16, the bevel gear pair 24, the transmission 26, and the differential gear 58 are housed in a case 70. The clutch K1 connects and disconnects the propeller shaft 18 and one of the bevel gear pair 24. The other of the bevel gear pair 24 is connected to a main shaft 28 of the transmission 26, which will be described later.

[0016] The transmission 26 is a so-called vehicular dog-type transmission that includes a main shaft 28 as a first rotating shaft and a countershaft 52 as a second rotating shaft, which are arranged horizontally and parallel to each other. The transmission 26 is configured to achieve multiple gear stages (speed stages) by slowing or speeding up the rotation of the main shaft 28 at a predetermined gear ratio γ (also referred to as a gear ratio) (= rotational speed of the main shaft 28 / rotational speed of the countershaft 52). The main shaft 28 is rotatable about a first axis C1, and the countershaft 52 is rotatable about a second axis C2. The countershaft 52 includes a main rotating shaft portion 54 and a gear rotating shaft portion 56 that are non-rotatably connected to each other by a spline fitting portion 52s. An output gear 56g provided on the gear rotating shaft portion 56 meshes with a final gear 58a provided on the differential gear 58, thereby connecting the countershaft 52 and the differential gear 58. The differential gear 58 and the pair of drive wheels 14 are connected via a pair of drive shafts 20. The pair of drive shafts 20 are arranged to be rotatable about a third axis C3 that is parallel to the second axis C2.

[0017] The transmission 26 includes a plurality of gear pairs 30. Each gear pair 30 includes a drive gear 32 fixed to the main shaft 28 so as not to rotate relative to the main shaft 28, and a driven gear 34 that is constantly meshed with the drive gear 32, is rotatable relative to the main rotary shaft portion 54, and is immovable in the second axis C2 direction. The gear pairs 30 are provided, in order from one side to the other in the first axis C1 direction (= second axis C2 direction), as a reverse gear pair 30a, a second-speed gear pair 30b, a first-speed gear pair 30c, a fourth-speed gear pair 30d, a fifth-speed gear pair 30e, a sixth-speed gear pair 30f, and a third-speed gear pair 30g. The reverse gear pair 30a has an intermediate gear 36 located between the drive gear 32 and the driven gear 34 to reverse the rotation direction. Hereinafter, unless otherwise specified, the reverse gear pair 30a to the third gear pair 30g will be referred to as "gear pair 30."

[0018] In the direction of the second axis C2, the transmission 26 includes switching mechanisms 40 on one side of the driven gear 34 of the reverse gear pair 30a, between the driven gears 34 of the second-speed gear pair 30b and the first-speed gear pair 30c, between the driven gears 34 of the fourth-speed gear pair 30d and the fifth-speed gear pair 30e, and between the driven gears 34 of the sixth-speed gear pair 30f and the third-speed gear pair 30g. The switching mechanisms 40 are each provided on the main rotation shaft portion 54 of the countershaft 52 so as to be non-rotatable relative to the main rotation shaft portion 54 and movable in the direction of the second axis C2. Each switching mechanism 40 has a switching meshing tooth 42 at a position facing the driven gear 34 in the direction of the second axis C2. Each of the driven gears 34 has gear-side meshing teeth 44 that can mesh with the switching meshing teeth 42 at a position facing the switching mechanism 40 in the direction of the second axis C2. The switching mechanism 40 having the switching meshing teeth 42 and the driven gear 34 having the gear-side meshing teeth 44 form a dog clutch 50, which is a meshing clutch.

[0019] The shift mechanism 60 includes: shift forks 62 supported on the fourth axis C4 so as to be axially movable; and each of the shift forks 62 engages with the switching mechanisms 40 to switch their meshing state; a shift barrel shaft 66 rotatably provided about a third axis C3 parallel to the second axis C2; and shift grooves 64 formed therein that define the movement position of the shift fork 62 in the direction of the second axis C2 via the shift fork 62; a plurality of (e.g., eight) engagement pins 72 fixed between a pair of flanges 68 fixed to the shaft end of the shift barrel shaft 66 and parallel to the third axis C3 at predetermined intervals (e.g., 45-degree intervals) in the circumferential direction; and a shift device 74 fixed to the case 70 that uses the engagement pins 72 to rotate the shift barrel shaft 66 at predetermined rotational angle intervals (e.g., 45 degrees) to change the gears of the transmission 26. In the transmission 26, the switching mechanism 40 is moved to a specified position in the direction of the second axis C2 in accordance with the rotational position of the shift barrel shaft 66, thereby switching the engagement and disengagement states of the dog clutch 50 and changing the speed.

[0020] FIG. 2 is a diagram illustrating the arrangement of the main shaft 28, the counter shaft 52, and the pair of drive shafts 20 as viewed from the direction of the second axis C2. The case 70 is formed by integrally assembling multiple case members together with fasteners such as bolts. In FIG. 2, only the outer edge of the case 70 where the fasteners are fastened is shown. Lubricating oil OIL is stored in the bottom of the case 70. The oil level position P1 is the height of the lubricating oil OIL stored in the bottom of the case 70 under normal conditions.

[0021] Fig. 2 specifically shows a mechanism of the shift device 74 that rotates the shift barrel shaft 66 by a predetermined rotation angle (e.g., 45 degrees) and operates it, while Fig. 3 shows a mechanism for transmitting an operating force. The shift device 74 includes an engagement recess 76 that receives two of the eight engagement pins 72, a ratchet pawl 84 that has inclined portions 78, 80 provided on the front and rear sides of the engagement recess 76 and is rotatable around the pin 82, and a spring 86 that biases the ratchet pawl 84 in a direction that constantly presses it against the engagement pin 72. The shift member 88 is equipped with a shift member 88 that has a circular cross section and is linearly movable in a tangential direction of the flange 68. The shift member 88 advances the engagement pins 72 one by one in association with its reciprocating axial movement, thereby reliably stopping the rotation of the shift barrel shaft 66 in increments of, for example, 45 degrees, without causing the shift barrel shaft 66 to over-rotate.

[0022] The shift device 74 includes a shift actuator 92 connected to one end of a bell crank 90 that is rotatable about a fifth axis C5 perpendicular to the fourth axis C4, and a connecting link 94 that connects the other end of the bell crank 90 to the shift member 88 and is rotatably connected to the other end of the bell crank 90 and the shift member 88. One end of the connecting link 94 is connected to the other end of the bell crank 90 via a connecting joint 98 that is rotatable relative to the other end of the bell crank 90 about a pin 96 that is parallel to the fifth axis C5. The other end of the connecting link 94 is connected to the shift member 88 via a ball joint 100 so as to be rotatable about the center (sphere center) of a spherical portion 102 of the ball joint 100.

[0023] The ball joint 100 comprises a ball shaft 104 having one end fastened to the connecting link 94 and the other end formed with a spherical portion 102, and a ball bearing shaft 108 having one end formed with a ball receiving portion 106 that rotatably accommodates the spherical portion 102 and the other end rotatably connected to the other end of the bell crank 90. ​​A lubricant such as grease is preferably contained within the ball receiving portion 106 that rotatably accommodates the spherical portion 102, and the lubricant is sealed within the ball receiving portion 106 by an oil seal. In this embodiment, the ball bearing shaft 108 constitutes the connecting link 94.

[0024] According to this embodiment, there are provided a plurality of types of gear pairs 30 that mesh with each other and are provided on a main shaft 28 and a counter shaft 52 that are parallel to each other, a shift fork 62 that operates a plurality of dog clutches 50 between the gears on the counter shaft 52 side of the gear pair 30 and the counter shaft 52, a shift barrel shaft 66 that has a plurality of shift grooves 64 that engage with the base ends of the shift forks 62, respectively, and that selectively establishes a plurality of gear stages at each predetermined rotation angle, and a plurality of engagement pins 72 that are arranged at equal intervals in the circumferential direction on the shaft end of the shift barrel shaft 6 .... and a shift member 88 that linearly reciprocates a ratchet pawl 84 with the ratchet pawl 84 having an engagement recess 76 that receives two of the engagement pins 72 and inclined portions 78, 80 on both sides of the engagement recess 76 while being pressed against the engagement pins 72. In this transmission 26, a shift device 74 of the transmission 26 applies an operating force to one end of a bell crank 90 and transmits the operating force to the shift member 88 from the other end, and includes a connecting link 94 that is rotatably connected to the other end of the bell crank 90 and the shift member 88. The connecting link 94 absorbs the arcuate motion of the other end of the bell crank 90 and transmits linear motion to the shift member 88 in the axial direction of the shift member 88, thereby smoothing the sliding of the shift member 88 and reducing the operating force required to move the shift member 88. This provides a shift device 74 of the transmission 26 that allows for faster shifting speeds.

[0025] Furthermore, according to this embodiment, the connecting link 94 and the shift member 88 are connected via a ball joint 100 so as to be rotatable about the spherical center of the ball joint 100. Because the ball joint 100 has a large sliding contact area, bending resistance is small even when a large operating force is momentarily applied, resulting in greater shifting speed.

[0026] Furthermore, according to this embodiment, the ball joint 100 comprises a ball shaft 104 having a spherical portion 102 at its end, and a ball bearing shaft 108 having a ball bearing portion 106 formed therein that rotatably accommodates the spherical portion 102 of the ball shaft 104 together with a lubricant such as grease. As a result, the lubricant such as grease allows smooth sliding between the spherical portion 102 and the ball bearing portion 106, thereby increasing the durability of the ball joint 100.

[0027] The above-described embodiments of the present invention are merely examples, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0028] For example, as shown in FIG. 4, instead of the shift actuator 92, a manual operation lever 110 can be used to input an operating force to one end of the bell crank 90. [Explanation of symbols]

[0029] 26: Transmission (vehicle dog-type transmission), 28: Main shaft (first rotating shaft), 30: Gear pair, 50: Dog clutch (dog clutch), 52: Countershaft (second rotating shaft), 62: Shift fork, 64: Shift groove, 66: Shift barrel shaft, 72: Engagement pin, 74: Shift device, 76: Engagement recess, 78, 80: Inclined portion, 84: Ratchet pawl, 88: Shift member, 90: Bell crank, 94: Connecting link, 100: Ball joint, 102: Spherical portion, 104: Ball shaft, 106: Ball receiving portion, 108: Ball receiving shaft

Claims

1. a shift barrel shaft having a plurality of shift grooves that engage with base ends of the shift forks, respectively, and that selectively establish a plurality of gear stages at each predetermined rotation angle; and a shift member that linearly reciprocates a plurality of engagement pins arranged at equal intervals in the circumferential direction on a shaft end of the shift barrel shaft, with a ratchet pawl having an engagement recess that receives two of the plurality of engagement pins and inclined portions on both sides of the engagement recess, while pressing the engagement pins against the engagement pins. In this shift device for a vehicle dog-type transmission, an operating force is applied to one end of a bell crank and transmitted from the other end to the shift member, a connecting link rotatably connected to the other end of the bell crank and the shift member, respectively; A shift device for a dog-type transmission for a vehicle.

2. The connecting link and the shift member are connected via a ball joint so as to be rotatable around the center of the ball joint.

2. A shift device for a dog-type transmission for a vehicle according to claim 1.

3. The ball joint includes a ball shaft having a spherical portion at an end thereof, and a ball bearing shaft having a ball bearing portion formed therein that accommodates the spherical portion of the ball shaft together with a lubricant so that the spherical portion can rotate.

3. A shift device for a dog-type transmission for a vehicle according to claim 2.

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