JP6607075B2 - Always meshing transmission - Google Patents

Description

  The present invention relates to a constant mesh transmission.

  Conventionally, in a transmission that changes the reduction gear ratio by switching the gear pair connected between the input shaft and the output shaft, when switching the reduction gear ratio, the non-circular gear pair is transitioned between the input shaft and the output shaft. As a result, a transmission has been proposed in which power is continuously transmitted even when the reduction ratio is switched.

  Patent Document 1 and Patent Document 2 describe a transmission including a non-circular gear pair that continuously transmits power when the reduction ratio is switched. For example, Patent Document 2 discloses a transmission in which one non-circular gear pair can be used for both upshifting and downshifting, with a clutch interposed between an input member and an output member. Thus, a configuration in which at least three first to third gear pairs and a non-circular gear pair are selectively connected is described. The non-circular gear pair includes a constant speed meshing section having the same speed reduction ratio as that of the gear pair, and a speed change meshing section in which the speed reduction ratio gradually increases or decreases between adjacent constant speed meshing sections. Is included in the reduction ratio reduction area from the maximum reduction ratio stage to the minimum reduction ratio stage and the reduction ratio increase area from the minimum reduction ratio stage to the maximum reduction ratio stage, respectively. It is a waste.

JP 2011-241840 A JP 2012-127482 A

  In the prior art, a transmission capable of constantly transmitting power is configured by connecting non-circular gears between fixed gears. For example, in addition to four sets of gear pairs, A pair of circular gears is necessary, and there is a problem that the volume increases compared to a manual transmission. In addition, since a clutch is required to switch between the circular gear and the non-circular gear, and it is necessary to switch the clutch while the non-circular gear is at a predetermined angle, there is a problem that the time and timing become severe. .

  The present invention has been made in view of the problems of the related art, and an object of the present invention is to provide a transmission that is high in volumetric efficiency and capable of constantly transmitting power by constantly engaging a gear.

  The present invention includes a first pinion gear and a second pinion gear that are spline fitted to an input shaft, a constant speed gear and a transmission gear that are spline fitted to an output shaft, and a constant speed gear and a transmission gear. And a moving mechanism for moving the first pinion gear and the second pinion gear in the direction of the rotation axis of the input shaft in conjunction with the movement of the output shaft in the direction of the rotation axis of the output shaft. A gear having a circular pitch curve with the same rotation center and a diameter r1 and a circular pitch curve with a diameter r2 (r2> r1), and the speed change gear is an arc having a diameter r1 at least in the first part. A pitch curve having an arc pitch curve with a diameter r2 at a second portion facing the first portion, a non-arc pitch curve connecting the first portion and the second portion, the first portion and the first portion; Have teeth with relatively high tooth heights at two sites, The first pinion gear and the constant speed gear mesh with each other at the time of transmission to transmit power from the input shaft to the output shaft, and the second pinion gear and the transmission gear do not mesh with each other. And the second pinion gear and the transmission gear mesh with each other in either the first part or the second part, and the constant speed gear and the transmission gear are rotated by the moving mechanism during the speed change. In conjunction with this, the first pinion gear and the second pinion gear are moved in the direction of the rotation axis of the input shaft so that the second pinion gear and the transmission gear mesh with each other to drive power from the input shaft to the output shaft. The first pinion gear and the constant speed gear do not mesh with each other, the first pinion gear and the constant speed gear mesh with each other at the end of the shift, and the second pinion gear and the transmission gear shift between the first part and the second part. Noiz Is a constant mesh type transmission, characterized in that the mesh or the other.

  In one embodiment of the present invention, the constant speed gear has teeth having a circular pitch curve with a diameter r1, a tooth having a circular pitch curve with a diameter r2, and a circular pitch curve with a diameter r3, the rotation centers of which are the same. The gears for transmission have a circular arc pitch curve with a diameter r1 at the first part and the second part opposite to the first part. A tooth having an arc pitch curve of diameter r2, a non-arc pitch curve connecting between the first part and the second part, and a tooth having a relatively high tooth height in the first part and the second part; Having an arc pitch curve with a diameter r2 and having an arc pitch curve with a diameter r3 at a second part facing the first part, and having a non-arc pitch curve connecting the first part and the second part, The first part and the second part have teeth having a relatively high tooth height.

  In another embodiment of the present invention, the constant speed gear and the transmission gear are arranged such that their tooth surfaces are in opposite directions.

  In still another embodiment of the present invention, the constant speed gear and the transmission gear are arranged so that their tooth surfaces face each other.

  In still another embodiment of the present invention, the moving mechanism has a speed change pin and a speed change cam, and the speed change pin engages with the speed change cam during the speed change, so that the constant speed gear and the speed change gear are changed. Move in the direction of the rotation axis of the output shaft.

  The first part and the second part are, for example, an angle range of 60 degrees around the rotation center, but are not limited thereto.

  According to the present invention, it is possible to obtain a transmission capable of constantly transmitting power from the input shaft to the output shaft by constantly engaging the gears. Therefore, slip loss is small and power transmission efficiency is improved. According to the present invention, the clutch can be eliminated by changing the meshing state by moving the constant speed gear and the speed change gear in the direction of the rotation axis of the output shaft by the moving mechanism during the speed change. Furthermore, according to the present invention, the increase in the gear position can be dealt with by adding teeth in the radial direction of the constant speed gear and the speed change gear.

It is a block diagram of the transmission in embodiment. FIG. 2 is a plan view of a constant speed gear of the transmission shown in FIG. 1. FIG. 2 is a plan view of a speed change gear of the transmission shown in FIG. 1. It is operation | movement explanatory drawing of the transmission in embodiment. It is a block diagram of the transmission in other embodiment. It is a block diagram of the transmission in other embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of a constantly meshing transmission according to the present embodiment. The continuously meshing transmission includes synchronization gears 12 and 14, pinion gears 16 and 18, constant speed gear 22, transmission gear 24, transmission cams 26 and 28, reduction pin 30, A speed pin 32 is provided.

  The synchronization gears 12 and 14 are spline-fitted to the input shaft 10 and mesh with each other to rotate synchronously.

  The pinion gear 16 is connected to the synchronization gear 12 and rotates together with the synchronization gear 12.

  The pinion gear 18 is connected to the synchronization gear 14 and rotates together with the synchronization gear 14. The pinion gears 16 and 18 are spline-fitted to the input shaft 10 and are movable in the direction of the arrow 100 in the drawing along the rotational axis direction of the input shaft 10.

  Both the constant speed gear 22 and the transmission gear 24 are spline-fitted to the output shaft 20 and can move in the direction of the arrow 200 in the drawing in the direction of the rotation axis of the output shaft 20. The constant speed gear 22 has teeth arranged on a concentric circle for each of a plurality of stages. For example, the constant speed gear 22 has teeth arranged on a circle for each of the first, second, and third stages. The speed change gear 24 corresponds to a plurality of stages of the constant speed gear 22 and has a plurality of non-circular teeth corresponding to the speed change between the stages. For example, when the constant speed gear 22 has three speeds, the speed change gear 24 has a non-circular tooth corresponding to a speed change between the first speed and the second speed, and between the second speed and the third speed. It has non-circular teeth corresponding to the speed change. The tooth height of the constant speed gear 22 is constant, while the gear height of the transmission gear 24 is not constant, and the tooth height at the predetermined portion is relatively high. The constant speed gear 22 and the transmission gear 24 are arranged back to back so that the surfaces on which the teeth are not formed face each other. The constant speed gear 22 can be meshed with the pinion gear 16, and the transmission gear 24 can be meshed with the pinion gear 18.

  The speed change cams 26 and 28 are formed on the output shaft 20, and the deceleration pin 30 and the speed increase pin 32 are engaged with the respective cam grooves. That is, at the start of the deceleration operation, the deceleration pin 30 moves and engages the transmission cam 26, and the constant speed gear 22 and the transmission gear 24 move by a certain amount in the direction of the arrow 200 by the cam groove of the transmission cam 26. To do. At the end of the deceleration operation, the deceleration pin 30 returns to the original position. Further, at the start of the speed increasing operation, the speed increasing pin 32 is engaged with the speed changing cam 28, and the constant speed gear 22 and the speed changing gear 24 are moved by a certain amount in the direction of the arrow 200 by the cam groove of the speed changing cam 28. . At the end of the speed increasing operation, the speed increasing pin 32 returns to the original position.

  FIG. 2A shows a plan view of the constant speed gear 22. The constant speed gear 22 has, for example, three stages, a first stage, a second stage, and a third stage, and teeth arranged concentrically corresponding to the first stage, the second stage, and the third stage, respectively. 22-1, 22-2 and 22-3. The pitch curves of the teeth 22-1, 22-2, and 22-3 are circular, and the diameters of the teeth 22-1, 22-2, and 22-3 are r1, r2, and r3, respectively. However, r1 <r2 <r3.

  FIG. 2B shows a plan view of the transmission gear 24. The speed change gear 24 includes a tooth 24-1 corresponding to a speed change between the first speed and the second speed of the three speed constant speed gear 22, and a speed change speed corresponding to a speed change between the second speed and the third speed. It has a circular tooth 24-2. The pitch curves of the teeth 24-1 and 24-2 are not circular but non-circular. The rotation centers of the teeth 24-1 and 24-2 are the same, and predetermined portions of the teeth 24-1 and 24-2, specifically, a part a (first part) and a part b (second part) facing each other. The teeth are higher than the other parts by a certain amount.

  The pitch curve of the part a of the tooth 24-1 is an arc, and the diameter thereof is equal to the diameter r1 of the first stage tooth 22-1 of the constant speed gear 22. Further, the pitch curve of the portion b facing the teeth 24-1 is also an arc, and the diameter thereof is equal to the diameter r2 of the second stage tooth 22-2 of the constant speed gear 22. The pitch curve in the section between the part a and the part b is a continuous curve connecting these arcs.

  The part a of the tooth 24-2 is an arc, and the diameter thereof is equal to the diameter r2 of the second stage tooth 22-2 of the constant speed gear 22. Further, the part b facing the teeth 24-2 is also an arc, and the diameter thereof is equal to the diameter r3 of the third stage tooth 22-3 of the constant speed gear 22. The pitch curve in the section between the part a and the part b is a continuous curve connecting these arcs.

  Accordingly, in the speed change gear 24, when the tooth 24-1 is traced clockwise from the part a of the tooth 24-1, the diameter gradually increases from the diameter r1, and reaches the diameter r2 at the part b of the tooth 24-1. Become. Further, when the tooth 24-2 is traced clockwise from the part a of the tooth 24-2, the diameter gradually increases from the diameter r2, and reaches the diameter r3 at the part b of the tooth 24-2. Such a continuous increase in diameter is utilized during speed-up operation. On the other hand, when the tooth 24-2 is traced clockwise from the part b of the tooth 24-2, the diameter gradually decreases from the diameter r3 and reaches the diameter r2 at the part a of the tooth 24-2. Further, when the tooth 24-1 is traced clockwise from the part b of the tooth 24-1, the diameter gradually decreases from the diameter r2, and reaches the diameter r1 at the part a of the tooth 24-1. During the deceleration operation, such a continuous decrease in diameter is used.

  In the above configuration, the speed change operation (speed increase operation or speed reduction operation) is performed in the following steps.

Step I: At constant speed, the pinion gear 16 meshes with the constant speed gear 22 to transmit power. For example, the pinion gear 16 meshes with the third stage tooth 22-3 of the constant speed gear 22 and transmits the power from the input shaft 10 to the output shaft 20. At this time, the pinion gear 18 basically does not mesh with the transmission gear 24. In FIG. 2A, the symbol I indicates that the third stage tooth 22-3 of the constant speed gear 22 and the pinion gear 16 are meshed at this position. However, even at the constant speed, the pinion gear 18 and the transmission gear 24 can mesh with a part of reference numerals II and IV described later.

Step II: Shifting start At the start of shifting, the deceleration pin 30 is engaged with the shifting cam 26, or the speed increasing pin 32 is engaged with the shifting cam 28, so that the constant speed gear 22 and the shifting gear 24 are The direction of the arrow 200 in FIG. 1, specifically, the right direction in FIG. 1, moves toward the pinion gear 16, and the pinion gear 18 meshes with the constant speed gear 22, while the pinion gear 18 is the speed change gear. The gear 24 is engaged with the gear 24 at the portion 24 having a high tooth. For example, when the speed is increased from the third speed to the second speed, the pinion gear 18 meshes with the speed change gear 24 at the portion b of the tooth 24-2 of the speed change gear 24. 2A and 2B, symbol II indicates that the third stage tooth 22-3 of the constant speed gear 22 and the pinion gear 16 mesh with each other at a part of this position, and the tooth 24-2 of the speed change gear 24. It shows that the pinion gear 18 meshes in a part of this position.

Step III: During shifting, the speed reduction pin 30 is engaged with the speed change cam 26 or the speed increase pin 32 is engaged with the speed change cam 28 and the constant speed gear 22 and the speed change gear 24 are engaged. 1, the pinion gear 16 and the pinion gear 18 move in the direction of the arrow 100 in FIG. As a result, the pinion gear 16 and the constant speed gear 22 are disengaged, and only the pinion gear 18 is engaged with the transmission gear 24. The teeth of the speed change gear 24 are non-circular whose diameter changes sequentially as described above. However, by moving the pinion gear 18 in the direction of the arrow 100, that is, in the diameter direction of the speed change gear 24, the pinion gear 18 changes speed. Continues meshing with the non-circular teeth of the gear 24. For example, when decelerating from the third stage to the second stage, the pinion gear 18 meshes with the speed change gear 24 at the portion b of the tooth 24-2 of the speed change gear 24 and further maintains the mesh with the tooth 24-2. Rotate as it is. In FIG. 2B, symbol III indicates that the teeth 24-2 of the speed change gear 24 and the pinion gear 18 are meshed at this position.

Step IV: End of shifting At the end of shifting, the deceleration pin 30 is engaged with the shifting cam 26, or the acceleration pin 32 is engaged with the shifting cam 28, and the constant speed gear 22 and the shifting gear 24 are 1 moves in the direction of the arrow 200, specifically, the left direction in FIG. 1 and away from the pinion gear 16, and the pinion gear 16 meshes with the constant speed gear 22, while the pinion gear 18 shifts. The gear 24 is engaged with the gear 24 at the portion 24 having a high tooth. For example, when the speed is increased from the third speed to the second speed, the pinion gear 18 meshes with the speed change gear 24 at the portion a of the tooth 24-2 of the speed change gear 24. 2A and 2B, the symbol IV indicates that the second stage tooth 22-2 of the constant speed gear 22 and the pinion gear 16 mesh with each other at a part of this position, and the tooth 24-2 of the speed change gear 24. It shows that the pinion gear 18 meshes in a part of this position. At the start of shifting, the pinion gear 16 meshed with the third stage tooth 22-3 of the constant speed gear 22, but at the end of shifting, the pinion gear 16 moved to the second stage tooth 22-2 of the constant speed gear 22. Note that the speed is changed from the third speed to the second speed. At the end of the speed change, the deceleration pin 30 or the speed increase pin 32 returns to the original position, and the movement of the constant speed gear 22 and the speed change gear 24 in the direction of the arrow 200 ends.

Step V: Constant speed When the constant speed is reached again, the pinion gear 16 meshes with the constant speed gear 22 to transmit power. For example, the pinion gear 16 meshes with the second stage tooth 22-2 of the constant speed gear 22, and transmits the power from the input shaft 10 to the output shaft 20. At this time, the pinion gear 18 does not mesh with the transmission gear 24. In FIG. 2A, the symbol V indicates that the second stage tooth 22-2 of the constant speed gear 22 and the pinion gear 16 are meshed at this position. However, as described above, the pinion gear 18 and the transmission gear 24 can mesh with each other even at a constant speed at some of the reference numerals II and IV.

  FIG. 3 schematically shows the operating state of the transmission in the present embodiment. This is the operation at the time of speed increase from the third stage to the second stage. FIG. 3A to FIG. 3D show states at each step during the speed increase from the third stage to the second stage, and the upper stage in each figure shows the constant speed gear 22 and the transmission gear 24. The lower part is a schematic diagram showing the engagement state of the pinion gears 16, 18, the constant speed gear 22, and the transmission gear 24.

  FIG. 3A is a state diagram corresponding to Step I, in which the pinion gear 16 is engaged with the third stage tooth 22-3 of the constant speed gear 22.

  FIG. 3B shows a state corresponding to Step II, where the pinion gear 16 meshes with the third stage tooth 22-3 of the constant speed gear 22, and the pinion gear 18 engages the tooth 24 of the speed change gear 24. It is the state which has meshed in site | part b of -2.

  FIG. 3C shows a state corresponding to Step III, in which the pinion gears 16 and 18 move in the direction of the arrow 100, and the constant speed gear 22 and the speed change gear 24 move in the direction of the arrow 200. The pinion gear 16 does not mesh with the constant speed gear 22 and only the pinion gear 18 meshes with the teeth 24-2 of the transmission gear 24. The maximum amount of movement of the pinion gears 16 and 18 is equal to the difference Δr = r3−r2 between the radius r3 and the radius r2. Further, the maximum amount of movement of the constant speed gear 22 and the transmission gear 24 is the difference Δh = the tooth height h2 at the parts a and b of the transmission gear 24 and the tooth height h1 at the other parts. It is equal to h2-h1. This maximum movement amount is equal to the fluctuation amount of the cam groove of the shifting cams 26 and 28.

  FIG. 3D shows a state corresponding to step IV, where the pinion gear 16 meshes with the second stage tooth 22-2 of the constant speed gear 22, and the pinion gear 18 engages with the tooth 24 of the transmission gear 24. It is the state which has meshed | engaged in the site | part a-2.

  Although FIG. 3 illustrates the operation at the time of speed increase from the third stage to the second stage, the operation can be similarly understood at the time of speed increase from the second stage to the first stage. That is, in Step I, the pinion gear 16 meshes with the second stage tooth 22-2 of the constant speed gear 22, and in Step II, the pinion gear 16 is engaged with the second stage tooth 22-2 of the constant speed gear 22. And the pinion gear 18 meshes with the portion b of the tooth 24-1 of the transmission gear 24. Next, in Step III, the pinion gears 16 and 18 move in the direction of the arrow 100, and the constant speed gear 22 and the speed change gear 24 move in the direction of the arrow 200, so that the pinion gear 16 meshes with the constant speed gear 22. Instead, only the pinion gear 18 meshes with the teeth 24-1 of the transmission gear 24. In Step IV, the pinion gear 16 meshes with the first stage tooth 22-1 of the constant speed gear 22, and the pinion gear 18 meshes with the part a of the tooth 24-1 of the transmission gear 24.

  Further, the same can be understood during deceleration from the first stage to the second stage. That is, in Step I, the pinion gear 16 meshes with the first stage tooth 22-1 of the constant speed gear 22, and in Step II, the pinion gear 16 engages the first stage tooth 22-1 of the constant speed gear 22. And the pinion gear 18 meshes with the part a of the tooth 24-1 of the transmission gear 24. Next, in Step III, the pinion gears 16 and 18 move in the direction of the arrow 100, and the constant speed gear 22 and the speed change gear 24 move in the direction of the arrow 200, so that the pinion gear 16 meshes with the constant speed gear 22. Instead, only the pinion gear 18 meshes with the teeth 24-1 of the transmission gear 24. In Step IV, the pinion gear 16 meshes with the second stage tooth 22-2 of the constant speed gear 22, and the pinion gear 18 meshes with the portion b of the tooth 24-1 of the transmission gear 24.

  Thus, in the present embodiment, the pinion gears 16 and 18 mesh with the constant speed gear 22 and the transmission gear 24 by the movement of the pinion gears 16 and 18 and the movement of the constant speed gear 22 and the transmission gear 24. It is possible to change the speed while controlling the state and maintaining the meshing state at all times. In addition, in the present embodiment, when the speed is increased, the number of concentric teeth of the constant speed gear 22 is increased by the number of stages, and the number of teeth of the speed change gear 24 is increased (for constant speed). Since the number of stages of the gear 22 is merely set to 1), there is no gear that does not transmit power only by increasing the diameters of the constant speed gear 22 and the transmission gear 24 even if the number of stages is increased. More volumetric efficiency. Furthermore, in the present embodiment, a constant meshing state can be realized without using a clutch. Depending on the type of vehicle on which the transmission is mounted, when only two speeds are sufficient, the constant speed gear 22 has teeth 22-1 and teeth 22-2, and the speed change gear 24 has teeth 24. Will have only -1. The transmission gear 24 is a gear that is used for both speed reduction and speed increase.

  In this embodiment, the constant speed gear 22 and the speed change gear 24 are spline-fitted to the output shaft 20 in a back-to-back manner as shown in FIG. 1, but the respective teeth face each other as shown in FIG. In this manner, the output shaft 20 may be splined to face each other. In this case, the synchronization gears 12 and 14 can be made unnecessary.

  Further, in this embodiment, as shown in FIG. 1, the shifting cams 26 and 28 are arranged on one side (right side in the figure) of the shifting gear 24, but the positions of the shifting cams 26 and 28 are For example, as shown in FIG. 5, speed change cams 26, 28 may be arranged between the constant speed gear 22 and the speed change gear 24, as shown in FIG. 5. It goes without saying that the deceleration pin 30 and the like are also arranged according to the position.

  FIG. 5 shows a perspective view of the transmission. By referring to FIG. 5, the form of the teeth of the transmission gear 24 will become clearer. In the figure, for convenience of explanation, only the tooth 24-1 is shown as the tooth of the speed change gear 24, but it should be noted that the tooth 24-2 having a common center therewith is actually formed. . The tooth height h2 in the part a and the part b may be h2> h1 as compared with the height h1 of the other part, but may be h2 = 2 * h1, for example.

  Further, as shown in FIG. 2B, the part a and the part b where the tooth height is increased are each defined as an angular range of 60 degrees around the rotation center. That is, the acceleration or deceleration timing appears in a section having a central angle of 60 degrees while the output shaft 20 makes one round. However, the central angle of 60 degrees is an example, and other angles may be used.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various deformation | transformation is possible.

  For example, in this embodiment, the constant speed gear 22 and the speed change gear 24 are moved in the direction of the rotation axis of the output shaft 20 using the speed change cams 26 and 28, the speed reduction pin 30, and the speed increase pin 32. However, the present invention is not limited to this, and any moving mechanism can be used. The moving mechanism moves the constant speed gear 22 and the speed change gear 24 from the start of the speed change to the end of the speed change so that the teeth of the speed change gear 24 and the pinion gear 18 are engaged with each other. It is moved in the direction of 10 rotation axes.

  The pinion gear 18 needs to keep meshing in a section between the part a and the part b of the speed change gear 24 during a shift, and therefore the pinion gear 18 is moved in the direction of the rotation axis of the input shaft 10, but is decelerated. It may be driven by external power as in the case of the pin 30 and the speed increasing pin 32, or may be moved without external power by providing a guard on the side surface of the pinion gear 18. The guard in this case can also be included in the moving mechanism.

  In the present embodiment, the two cams 26 and 28 for shifting are illustrated, but deceleration and acceleration may be executed with only a single cam.

  The pinion gears 16 and 18 may be helical gears in addition to spur gears.

  Furthermore, it will be apparent to those skilled in the art that in this embodiment, the input shaft 10 may be used as an output shaft and the output shaft 20 may be used as an input shaft.

10 input shaft, 12, 14 synchronization gear, 16 pinion gear (first pinion gear), 18 pinion gear (second pinion gear), 20 output shaft, 22 constant speed gear, 24 speed change gear, 26, 28 speed change Cam, 30 deceleration pin, 32 acceleration cam.

Claims (5)

A first pinion gear and a second pinion gear that are spline-fitted to the input shaft;
A constant speed gear and a transmission gear that are spline-fitted to the output shaft;
A moving mechanism for moving the constant-speed gear and the transmission gear in the direction of the rotation axis of the output shaft, and moving the first pinion gear and the second pinion gear in the direction of the rotation axis of the input shaft in conjunction with the gear;
With
The constant speed gear has at least teeth having a circular pitch curve with a diameter r1 and having a circular pitch curve with a diameter r2 (r2> r1), the rotation centers of which are the same.
The transmission gear has an arc pitch curve with a diameter r1 at least at a first portion, an arc pitch curve with a diameter r2 at a second portion facing the first portion, and between the first portion and the second portion. A tooth having a relatively high tooth height at the first part and the second part,
At the constant speed, the first pinion gear and the constant speed gear mesh with each other to transmit power from the input shaft to the output shaft, and the second pinion gear and the shift gear do not mesh with each other. The speed gear is engaged and the second pinion gear and the transmission gear are engaged at one of the first part and the second part, and the constant speed gear and the transmission gear are rotated on the output shaft by the moving mechanism during the speed change. The first pinion gear and the second pinion gear are moved in the axial direction in conjunction with the movement of the first pinion gear and the second pinion gear in the direction of the rotation axis of the input shaft. Power is transmitted and the first pinion gear and the constant speed gear do not mesh with each other. At the end of the shift, the first pinion gear and the constant speed gear mesh with each other, and the second pinion gear and the transmission gear shift between the first portion and the second gear. Izu of the part Constant mesh type transmission, characterized in that the meshing or the other. The constant mesh transmission according to claim 1,
The constant speed gear has teeth having a circular pitch curve with a diameter r1, the teeth having a circular pitch curve with a diameter r2, and teeth having a circular pitch curve with a diameter r3 (r3>r2> r1). )
The transmission gear has an arc pitch curve with a diameter r1 at a first portion and a circular pitch curve with a diameter r2 at a second portion opposite to the first portion, the rotation centers of which are the same. The first part has a non-arc pitch curve connecting between the second parts, the tooth having a relatively high tooth height in the first part and the second part, and the arc pitch curve of the diameter r2 in the first part. And a second part that has an arc pitch curve with a diameter r3, a non-arc pitch curve that connects the first part and the second part, and a relatively high tooth height at the first part and the second part. A constantly meshing transmission characterized by having high teeth. In the always meshing transmission according to any one of claims 1 and 2,
The constant-speed gear and the transmission gear are arranged so that their tooth surfaces are in opposite directions. In the always meshing transmission according to any one of claims 1 and 2,
The constant speed gear and the transmission gear are arranged so that their tooth surfaces face each other. In the always meshing transmission according to any one of claims 1 and 2,
The moving mechanism has a speed change pin and a speed change cam, and the speed change pin and the speed change gear are moved in the direction of the rotation axis of the output shaft by engaging the speed change pin with the speed change cam during the speed change. Always meshing transmission characterized by

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