JP2014240670A - Gear shift stage position detecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear shift stage position detecting mechanism capable of reducing costs.SOLUTION: A gear shift stage position detecting mechanism 300 detecting a position of a gear shift stage of a transmission changing the gear shift stage by switching a position of a shift fork interlocking with a cam shaft 70 by rotating the cam shaft 70 around a shaft center, includes a first detection row 73 and a second detection row 74 (detection rows) constituted by forming recessed portions on an outer peripheral face of the cam shaft 70 at prescribed intervals in the circumferential direction, and a first sensor 80 and a second sensor 90 (detecting means) disposed in opposition to the detection rows and detecting whether the recessed portions are located on the opposed positions or not. Two sets of the detection rows and the detecting means corresponding to the detection rows are provided, and the gear shift stage position is detected on the basis of combination of results of the detection by the plurality of detecting means.

Description

  The present invention relates to a technology of a gear position detection mechanism that detects the position of a gear position of a transmission mechanism.

  Conventionally, the technology of a gear position detection mechanism that detects the position of a gear position of a transmission mechanism has been publicly known. For example, as described in Patent Document 1.

  The gear position detection mechanism described in Patent Document 1 includes a shift select shaft that moves in response to an operation (shift operation) for switching the gear position by the operator, a guide groove provided in the shift select shaft, And a protrusion inserted into the guide groove. With such a configuration, the movement of the shift select shaft is guided by the guide groove and the protrusion.

  In addition, the guide groove is formed so that the depth of the bottom surface at a position corresponding to each shift stage is different, and the depth of the bottom surface of the guide groove can be detected at the tip of the protrusion. A detection sensor is provided. In such a configuration, the current gear position can be detected (determined) based on the depth of the bottom surface of the guide groove detected by the detection sensor.

  However, the detection sensor for detecting the difference in the depth of the bottom surface of the groove as described in Patent Document 1 is usually expensive. In addition, adjustment is required to accurately detect the depth of the bottom surface of the groove when mounting. For this reason, it is disadvantageous in that the cost of parts and assembly may increase.

  In addition, in a speed change mechanism capable of switching the gear position by rotating the shaft-shaped member around the shaft center, by detecting the rotation angle of the shaft-shaped member with a detection sensor, Techniques for detecting the current gear position are known.

  However, such a detection sensor capable of detecting the rotation angle is also usually expensive, and adjustment is required when it is attached, which is disadvantageous in that the cost may increase.

JP 2012-21626 A

  The present invention has been made in view of the above situation, and a problem to be solved is to provide a gear position detection mechanism capable of reducing the cost.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the first aspect of the present invention, the position of the speed change stage of the speed change mechanism that changes the speed change position by switching the position of the shift fork linked to the speed change operation shaft by rotating the speed change operation shaft about the axis. A shift position detecting mechanism for detecting, provided on the outer circumferential surface of the shift operation shaft, corresponding to the detection row, and a detection row in which concave portions or convex portions are formed at predetermined intervals in the circumferential direction; And a detecting unit that is arranged so as to face the detection row and detects whether the concave portion or the convex portion is at a position facing the detection row, and the detection row and the detection row corresponding to the detection row A plurality of sets of detection means are provided, and the gear position is detected based on a combination of detection results from each of the plurality of detection means.

  According to a second aspect of the present invention, the speed change operation shaft is housed inside a speed change case in which the speed change mechanism is housed.

  According to a third aspect of the present invention, the shift operation shaft is formed with a guide groove for guiding the shift fork to a predetermined position, and the shift fork is engaged with the guide groove.

  According to a fourth aspect of the present invention, the concave portion or the convex portion is a concave portion having a shape in which a part of the outer peripheral surface of the transmission operation shaft is recessed.

  According to a fifth aspect of the present invention, the speed change mechanism has four speed stages, the detection row and the detection means are provided in two sets, and the four speed stages are based on combinations of detection results from the two detection means. The gear position is detected.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, it is possible to detect a large number of gear positions with a small number of detection means, and it is possible to reduce the parts cost. Moreover, since it is sufficient for the detection means to be able to detect only the presence or absence of a concave portion or a convex portion, the detection means can be simplified, and the component cost can be further reduced. In addition, since such a detection means does not require (or is simple) an adjustment operation for installation, the assembly cost can be reduced.

  According to the second aspect, it is possible to protect the speed change operation shaft for detecting the position of the speed stage.

  According to the third aspect of the present invention, a concave portion or a convex portion is formed in the member (shifting operation shaft) that switches the position of the shift fork directly, and the concave and convex portion is detected. The influence can be suppressed small, and the error between the actual gear position and the detected gear position can be reduced.

  In Claim 4, the process for forming a recessed part or a convex part (recessed part) becomes easy.

  According to the fifth aspect of the present invention, it is possible to provide an optimum gear position detection mechanism for detecting four gear positions.

The side view which showed the whole structure of the multipurpose work vehicle. Similarly, a schematic plan view. A sectional view of a transmission showing a state of power transmission. Sectional drawing of a transmission which shows the structure regarding switching of a gear stage. Similarly, an exploded perspective view. (A) The side view which shows a detent mechanism. (B) The figure which shows a detent mechanism in case a gear stage is a reverse gear. (C) The figure which shows a detent mechanism in case a gear stage is a neutral stage. (D) The figure which shows a detent mechanism in case a gear stage is a high speed stage. (E) The figure which shows a detent mechanism in case a gear stage is a low speed stage. The perspective view which showed the speed change operation mechanism in the vicinity of a transmission case. The perspective view which showed the speed change operation mechanism in a boarding part. The schematic diagram which showed the structure of the gear position detection mechanism. (A) The top view which showed the cam shaft. (B) The figure which showed each cross section of the cam shaft. FIG. 3 is a development view of a camshaft and a diagram showing a combination of detection results by a sensor. (A) The figure which showed each cross section of the cam shaft in case a gear stage is a reverse gear. (B) The figure which similarly showed each cross section of the cam shaft in the case of a neutral stage. (A) The figure which showed each cross section of the cam shaft in case a gear stage is a high speed stage. (B) The figure which similarly showed each cross section of the cam shaft in the case of a low speed stage. (A) Sectional drawing which showed the modification of the detent mechanism. (B) Similarly, a side view. The expanded view of the cam shaft which concerns on 2nd embodiment, and the figure which showed the combination of the detection result by a sensor. The expanded view of the cam shaft which concerns on 3rd embodiment, and the figure which showed the combination of the detection result by a sensor.

  Hereinafter, the multipurpose work vehicle 1 including the gear position detection mechanism 300 according to an embodiment (first embodiment) of the present invention will be described.

  The multipurpose work vehicle 1 is an embodiment of a work vehicle, and the work vehicle to which the gear position detection mechanism according to the present invention can be applied is not limited to this. That is, the work vehicle may be other agricultural vehicles, construction vehicles, industrial vehicles, or the like.

  First, the overall configuration of the multipurpose work vehicle 1 will be described with reference to FIGS. 1 and 2.

  The multi-purpose work vehicle 1 mainly includes a body frame 2, a front wheel 3, a bonnet 4, a riding section 5, an engine 6, a belt type continuously variable transmission (hereinafter simply referred to as "CVT") 7, a transmission 8, a rear wheel 9, and a loading platform. 10, a rear axle 11, a transmission shaft 12, a differential 13 and a front axle 14 are provided.

  A pair of left and right front wheels 3 and a bonnet 4 are provided at the front portion of the body frame 2. In the middle part of the front and rear of the vehicle body frame 2, a steering wheel 5a for steering the front wheels 3, a seat 5b for a driver to sit on, and a riding part 5 in which a shift lever 230, a liquid crystal display unit 301 and the like, which will be described later, are arranged. Is provided. At the rear of the vehicle body frame 2, an engine 6, a CVT 7 as a main transmission, a transmission 8 as an auxiliary transmission housed in a transmission case 8a, a pair of left and right rear wheels 9, a loading platform 10, and the like are provided.

  The power from the engine 6 is first transmitted to the CVT 7 and is shifted by the CVT 7. The power shifted by the CVT 7 is then transmitted to the transmission 8 and is shifted by the transmission 8. The power shifted by the transmission 8 is transmitted to the pair of left and right rear wheels 9 via a differential for the rear wheel 9 (not shown) of the transmission 8 and the pair of left and right rear axles 11.

  Further, the power changed by the transmission 8 is transmitted to the front wheel differential 13 through the transmission shaft 12. The power transmitted to the differential device 13 is transmitted to the pair of left and right front wheels 3 via the pair of left and right front axles 14.

  Thus, the multipurpose work vehicle 1 can travel (forward or reverse) at an arbitrary speed by arbitrarily shifting the power from the engine 6 by the CVT 7 and the transmission 8.

  Next, the configuration of the transmission 8 as an embodiment of the speed change mechanism according to the present invention will be described with reference to FIGS.

  The transmission 8 is accommodated in the transmission case 8a. Lubricating oil for lubricating each part of the transmission 8 is stored in the transmission case 8a. The transmission 8 mainly includes an input shaft 20, a transmission shaft 30, a reverse shaft 40, an output shaft 50, a fork rod 60, a cam shaft 70, a first sensor 80, a second sensor 90, a neutral sensor 100, an operation rod 110, and a cam rod 120. It has.

  An input shaft 20 shown in FIG. 3 is an axis to which power shifted in the CVT 7 is input. The input shaft 20 is rotatably supported by the transmission case 8a with the longitudinal direction facing left and right. A first low speed gear 21, a first high speed gear 22, and a first reverse gear 23 are integrally formed on the input shaft 20 in order from the left. The right end portion of the input shaft 20 is splined to the output shaft 7a of the CVT 7. As a result, the power shifted in the CVT 7 can be transmitted from the output shaft 7 a to the input shaft 20.

  The speed change shaft 30 shown in FIGS. 3 and 4 is an axis for changing the speed stage (speed change ratio) in the transmission 8. The transmission shaft 30 is rotatably supported by the transmission case 8a with its longitudinal direction facing left and right. A second low speed gear 31, a second high speed gear 32, and a second reverse gear 33 are provided on the transmission shaft 30 so as to be relatively rotatable in order from the left. The second low speed gear 31 is meshed with the first low speed gear 21 of the input shaft 20, and the second high speed gear 32 is meshed with the first high speed gear 22 of the input shaft 20.

  The transmission shaft 30 is provided with a first shifter 34 and a second shifter 35 that are relatively unrotatable and slidable in the left-right direction. The first shifter 34 is disposed between the second low speed gear 31 and the second high speed gear 32, and the second shifter 35 is disposed to the left of the second reverse gear 33.

  The first shifter 34 meshes with the second low speed gear 31 and meshes with the second high speed gear 32 and the low speed position L that allows the second low speed gear 31 and the transmission shaft 30 to rotate integrally. Thus, the second high-speed gear 32 and the transmission shaft 30 are slid into a high-speed position H where the second high-speed gear 32 and the transmission shaft 30 can rotate integrally, and a neutral position N where the second low-speed gear 31 and the second high-speed gear 32 do not mesh. It is possible to move it.

  The second shifter 35 meshes with the second reverse gear 33 so that the second reverse gear 33 and the transmission shaft 30 can rotate integrally, and the second reverse gear 33 does not mesh with the second reverse gear 33. It is possible to slide to the neutral position N.

  In addition, a first reduction gear 36 is spline-fitted near the right end of the transmission shaft 30.

  The reverse shaft 40 shown in FIG. 4 is for changing the rotational direction of the power. The reverse shaft 40 is supported by the transmission case 8a so as not to rotate with its longitudinal direction turned to the left and right. A third reverse gear 41 is provided on the reverse shaft 40 so as to be relatively rotatable. The third reverse gear 41 is meshed with the first reverse gear 23 (not shown) of the input shaft 20 and the second reverse gear 33 of the transmission shaft 30.

  The output shaft 50 shown in FIG. 3 is a shaft for transmitting the power shifted in the transmission 8 to the front wheels 3 and the rear wheels 9. The output shaft 50 is rotatably supported by the transmission case 8a with its longitudinal direction facing left and right. A second reduction gear 51 is provided in the vicinity of the right end portion of the output shaft 50 so as to be relatively unrotatable. The second reduction gear 51 is engaged with the first reduction gear 36 of the transmission shaft 30. In addition, a pinion gear 52 is integrally formed in the left and right middle part of the output shaft 50 (to the left of the second reduction gear 51).

  The pinion gear 52 can transmit power to the differential for the rear wheel 9 via a gear (not shown) or the like. As a result, the power from the transmission 8 is transmitted from the output shaft 50 to the rear wheel 9 via the differential. The second reduction gear 51 can transmit power to the transmission shaft 12 via a gear (not shown) or the like. As a result, the power from the transmission 8 is transmitted from the output shaft 50 to the front wheel 3 via the transmission shaft 12 and the like.

  The fork rod 60 shown in FIGS. 4 and 5 is for changing the positions of the first shifter 34 and the second shifter 35 of the transmission shaft 30. The fork rod 60 is supported by the transmission case 8a in a non-rotatable manner with the longitudinal direction facing left and right. The fork rod 60 is provided with a first shift fork 61 and a second shift fork 62 slidable in the left-right direction in order from the left. The first shift fork 61 is engaged with the first shifter 34 so as to be able to slide integrally with the first shifter 34 of the transmission shaft 30. The second shift fork 62 is engaged with the second shifter 35 so as to be slidable integrally with the second shifter 35 of the transmission shaft 30.

  The cam shaft 70 is an embodiment of the speed change operation shaft according to the present invention, and is for changing the positions of the first shift fork 61 and the second shift fork 62. The cam shaft 70 is a shaft-shaped member formed in a substantially cylindrical shape. Both end portions of the cam shaft 70 are formed (reduced diameter) so as to have a smaller diameter than the center portion. The cam shaft 70 is supported by the transmission case 8a at both end portions (reduced diameter portions) thereof with the longitudinal direction turned to the left and right, and is rotatable about the axis. A first guide groove 71 and a second guide groove 72 are formed on the outer peripheral surface of the cam shaft 70 in order from the left.

  The first guide groove 71 is a groove formed over the circumferential direction of the cam shaft 70 at a position generally facing the first shift fork 61. The first guide groove 71 is formed by being appropriately bent left and right. A first protrusion 61 a formed on the first shift fork 61 is inserted into the first guide groove 71. Thus, when the cam shaft 70 rotates, the first shift fork 61 slides to the left and right according to the bending of the first guide groove 71.

  Similarly, the second guide groove 72 is formed at a position that generally faces the second shift fork 62. A second protrusion 62 a formed on the second shift fork 62 is inserted into the second guide groove 72.

  A first detection row 73, a second detection row 74, and a neutral detection recess 75 are formed on the outer peripheral surface of the cam shaft 70. The first detection row 73, the second detection row 74, and the neutral detection recess 75 constitute a gear position detection mechanism 300 for detecting the position of the gear position of the transmission 8. The details of the gear position detection mechanism 300 will be described later.

  Further, an operation gear 76 and a cam plate 77 are provided in the vicinity of the right end portion of the cam shaft 70 so as to be relatively unrotatable.

  The cam plate 77 shown in FIGS. 5 and 6 is a plate-like member whose plate surface is directed in the left-right direction. On the outer periphery of the cam plate 77, a plurality of recesses (first recess 77a, second recess 77b, third recess 77c, and fourth recess 77d) are formed at predetermined intervals.

  The first sensor 80, the second sensor 90, and the neutral sensor 100 shown in FIG. 4 are for detecting the rotational position of the cam shaft 70. The first sensor 80, the second sensor 90, and the neutral sensor 100 are arranged in order in the left and right rows, and are disposed so as to face the camshaft 70 in the transmission case 8a. The first sensor 80, the second sensor 90, and the neutral sensor 100 constitute a gear position detection mechanism 300. The first sensor 80 and the second sensor 90 are an embodiment of the detection means according to the present invention. The details of the gear position detection mechanism 300 will be described later.

  The operation rod 110 shown in FIG. 5 is for rotating the cam shaft 70. The operation rod 110 is rotatably supported by the transmission case 8a with its longitudinal direction turned to the left and right. The left end portion of the operating rod 110 extends through the transmission case 8a to the outside of the transmission case 8a. In the vicinity of the right end portion of the operation rod 110, the sector gear 111 is provided so as to be relatively unrotatable. The sector gear 111 is meshed with the operation gear 76 of the cam shaft 70.

  The cam rod 120 shown in FIGS. 5 and 6 is intended to make it easier to hold the cam shaft 70 at a predetermined rotational position. The cam shaft 70 is supported by the transmission case 8a so as not to rotate with its longitudinal direction turned to the left and right. The cam rod 120 is provided so that one end (rear end) of the arm 121 is relatively rotatable. A roller 122 is provided at the other end (front end) of the arm 121 so as to be rotatable. The roller 122 is disposed so as to contact the cam plate 77 of the cam shaft 70 from above. The cam rod 120 is provided with a spring 123 that urges the front end of the arm 121 downward. The roller 122 provided at the front end of the arm 121 is always pressed against the cam plate 77 by the urging force of the spring 123.

  Next, the state of power transmission by the transmission 8 configured as described above will be described with reference to FIGS. 3 and 4. The transmission 8 has a “neutral stage N” in which the multi-purpose work vehicle 1 does not travel, a “high speed stage H” that travels at a high speed, a “low speed stage L” that travels at a low speed, and a “reverse stage R” that travels backward as a shift stage. .

  First, the case where the transmission 8 is in the neutral stage N will be described. In this case, as shown in FIG. 4, the first shifter 34 is switched to the neutral position N, and the second shifter 35 is switched to the neutral position N.

  In this case, each gear of the transmission shaft 30 that meshes with each gear of the input shaft 20 is rotatable relative to the transmission shaft 30. For this reason, the power transmitted from the CVT 7 to the input shaft 20 is not transmitted to the transmission shaft 30. Therefore, the front wheel 3 and the rear wheel 9 are not driven, and the multipurpose work vehicle 1 is in a stopped state (a state where it cannot travel).

  Next, the case where the gear position of the transmission 8 is the high speed stage H will be described. In this case, the first shifter 34 is switched to the high speed position H, and the second shifter 35 is switched to the neutral position N.

  In this case, since the second high speed gear 32 can rotate integrally with the transmission shaft 30, the power transmitted from the CVT 7 to the input shaft 20 is transmitted via the first high speed gear 22 and the second high speed gear 32. Is transmitted to the transmission shaft 30. Further, the power is transmitted to the output shaft 50 through the first reduction gear 36 and the second reduction gear 51, and is transmitted from the output shaft 50 to the front wheels 3 and the rear wheels 9. When the gear position of the transmission 8 is the high speed stage H, the multipurpose work vehicle 1 can move forward at high speed.

  Next, the case where the gear position of the transmission 8 is the low speed stage L will be described. In this case, the first shifter 34 is switched to the low speed position L, and the second shifter 35 is switched to the neutral position N.

  In this case, since the second low speed gear 31 can rotate integrally with the transmission shaft 30, the power transmitted from the CVT 7 to the input shaft 20 is transmitted via the first low speed gear 21 and the second low speed gear 31. Is transmitted to the transmission shaft 30. Further, the power is transmitted to the output shaft 50 through the first reduction gear 36 and the second reduction gear 51, and is transmitted from the output shaft 50 to the front wheels 3 and the rear wheels 9. When the gear position of the transmission 8 is the low speed stage L, the multi-purpose work vehicle 1 can move forward at a low speed because the speed ratio (reduction ratio) in the transmission 8 is larger than when the gear stage is the high speed stage H. It becomes.

  Next, the case where the transmission 8 is in the reverse speed R will be described. In this case, the first shifter 34 is switched to the neutral position N, and the second shifter 35 is switched to the reverse position R.

  In this case, since the second reverse gear 33 can rotate integrally with the transmission shaft 30, the power transmitted from the CVT 7 to the input shaft 20 is transmitted to the first reverse gear 23, the third reverse gear 41, and the It is transmitted to the transmission shaft 30 via the second reverse gear 33. Further, the power is transmitted to the output shaft 50 through the first reduction gear 36 and the second reduction gear 51, and is transmitted from the output shaft 50 to the front wheels 3 and the rear wheels 9. When the speed of the transmission 8 is the reverse speed R, the power is transmitted through the third reverse gear 41 when power is transmitted from the input shaft 20 to the speed change shaft 30. The direction of power (direction of rotation) is reversed. Therefore, when the gear position of the transmission 8 is the reverse speed R, the multipurpose work vehicle 1 can reverse.

  Next, the manner in which the gear position of the transmission 8 configured as described above is switched will be described with reference to FIGS.

  When the operation rod 110 is rotated by a shift operation mechanism 200 described later, the cam shaft 70 is rotated via the sector gear 111 and the operation gear 76. When the cam shaft 70 rotates, the first shift fork 61 and the second shift fork 62 slide to the left and right while being guided by the first guide groove 71 and the second guide groove 72 formed in the cam shaft 70. When the first shift fork 61 and the second shift fork 62 slide to the left and right, the first shifter 34 and the second shifter 35 engaged with the first shift fork 61 and the second shift fork 62 slide to the left and right. . As a result, the gear position of the transmission 8 is switched to the neutral stage N, the high speed stage H, the low speed stage L, or the reverse stage R.

  Note that the transmission 8 according to the present embodiment is rotated to the reverse stage R when the camshaft 70 is most rotated counterclockwise in the left side view, and is rotated one stage clockwise from the rotational position of the reverse stage R. In the case of the neutral stage N, in the case of one stage clockwise rotation from the rotational position of the neutral stage N, in the case of one stage clockwise rotation from the rotational position of the high speed stage H (clockwise rotation). To the low speed stage L, respectively.

  Further, when the cam shaft 70 rotates most counterclockwise in the left side view, that is, when the transmission 8 is switched to the reverse gear R, the cam plate 77 that rotates integrally with the cam shaft 70 The roller 122 is pressed against the first recess 77a (see FIG. 6B). As a result, the rotational position of the cam plate 77 becomes difficult to move, and it is possible to obtain a clear operational feeling when the gear position is switched to the reverse gear R (force to keep the gear position at the reverse gear R). it can.

  Similarly, when the transmission 8 is switched to the neutral stage N, the second recess 77b of the cam plate 77 (see FIG. 6C), and when the transmission 8 is switched to the high speed stage H, the third of the cam plate 77 is switched. When switching to the recess 77c (see FIG. 6 (d)) and switching to the low speed stage L, the rollers 122 are pressed against the fourth recesses 77d of the cam plate 77 (see FIG. 6 (e)), respectively. A clear operational feeling when switching to can be obtained.

  Thus, the cam plate 77, the cam rod 120, etc. constitute a so-called detent mechanism.

  Next, a speed change operation mechanism 200 for the operator to switch the gear position of the transmission 8 will be described with reference to FIGS. 5, 7, and 8. The speed change operation mechanism 200 mainly includes an operation arm 210, a push-pull cable 220, a speed change lever 230, and a lever guide 240.

  The operation arm 210 shown in FIGS. 5 and 7 is for rotating the operation rod 110. The operation arm 210 is disposed on the left side of the transmission case 8a. One end of the operation arm 210 is connected to the left end portion of the operation rod 110 extending to the outside of the transmission case 8a so as to be relatively unrotatable. The other end of the operation arm 210 extends substantially downward.

  The push-pull cable 220 shown in FIGS. 7 and 8 is for rotating the operation arm 210. One end of the push-pull cable 220 extends to the left side of the transmission case 8 a and is connected to the other end of the operation arm 210. The other end of the push-pull cable 220 is extended to the riding section 5.

  The shift lever 230 shown in FIG. 8 is for pushing and pulling the push-pull cable 220. The transmission lever 230 includes a connecting portion 231 connected to the push-pull cable 220 and an operation portion 232 that is operated by a driver holding the hand.

  The connecting portion 231 is rotatably supported by a front / rear rotation shaft 231a whose longitudinal direction is directed to the left and right. The other end of the push-pull cable 220 is connected to the front end of the connecting portion 231.

  The operation unit 232 is coupled to the coupling unit 231 so as to be relatively rotatable by a left and right rotation shaft 232a whose longitudinal direction is substantially directed in the front-rear direction. The upper end of the operation unit 232 extends upward to the vicinity (right side) of the steering wheel 5a. The operation unit 232 is always urged rightward by the spring 232b.

  The lever guide 240 guides the speed change lever 230. The lever guide 240 is a substantially rectangular plate-shaped member. The lever guide 240 is formed with a guide groove 240 a for guiding the speed change lever 230. The guide groove 240a is formed in a shape that is generally long in the front-rear direction and bent appropriately to the left and right. The transmission lever 230 is inserted through the guide groove 240a.

  In the shift operation mechanism 200 configured as described above, when the shift lever 230 is rotated (operated) back and forth, the rotation is transmitted to the operation arm 210 via the push-pull cable 220, and the operation arm 210 is Rotate. When the operation arm 210 is rotated, the operation rod 110 connected to the operation arm 210 is rotated, so that the gear position of the transmission 8 can be switched.

  When the shift lever 230 is at the position (neutral position N) shown in FIG. 8 of the lever guide 240 (guide groove 240a), the shift stage of the transmission 8 is the neutral stage N. When the speed change lever 230 is rotated from the neutral position N to the front position (high speed position H) as it is, the gear position of the transmission 8 is switched to the high speed stage H. When the speed change lever 230 is turned leftward from the high speed position H to the further forward position (low speed position L), the gear position of the transmission 8 is switched to the low speed stage L. When the shift lever 230 is rotated leftward from the neutral position N to the rear position (reverse position R), the transmission stage of the transmission 8 is switched to the reverse stage R.

  Next, the gear position detecting mechanism 300 that detects the position of the gear position of the transmission 8 will be described with reference to FIG. 4 and FIGS. 9 to 13. The gear position detection mechanism 300 mainly includes a first sensor 80, a second sensor 90, a neutral sensor 100, a first detection row 73 of the camshaft 70, a second detection row 74 and a neutral detection recess 75, and an ECU 302 and a liquid crystal display portion. 301.

  The first sensor 80, the second sensor 90, and the neutral sensor 100 shown in FIGS. 4 and 9 are contact sensors that detect a recess formed in the outer peripheral surface of the cam shaft 70. The first sensor 80, the second sensor 90, and the neutral sensor 100 each have a detection end 81, a detection end 91, and a detection end 101 that can be expanded and contracted.

  The detection end 81, the detection end 91, and the detection end 101 are each urged so as to always expand. The detection end 81, the detection end 91, and the detection end 101 can be compressed by applying an external force. The first sensor 80, the second sensor 90, and the neutral sensor 100 emit detection signals only when the detection end 81, the detection end 91, and the detection end 101 are compressed. Therefore, by determining whether or not the first sensor 80, the second sensor 90, and the neutral sensor 100 are emitting detection signals, the detection end 81, the detection end 91, and the detection end 101 are each extended to the maximum extent. It is possible to detect whether it is in a state (so-called OFF state) or a compressed state (so-called ON state).

  The first sensor 80, the second sensor 90, and the neutral sensor 100 are fixed to the transmission case 8a so as to penetrate the transmission case 8a. The first sensor 80, the second sensor 90, and the neutral sensor 100 are arranged in order on the left and right sides so that the detection end 81, the detection end 91, and the detection end 101 face the cam shaft 70 in the transmission case 8a. Arranged.

  The first sensor 80 and the second sensor 90 are connected to an ECU 302 described later. The neutral sensor 100 is connected to an engine start circuit 6a for starting the engine 6.

  The first detection row 73 and the second detection row 74 of the cam shaft 70 shown in FIGS. 9 to 11 are formed by forming recesses on the outer peripheral surface of the cam shaft 70 at predetermined intervals in the circumferential direction.

  The first detection row 73 is formed at a position facing the first sensor 80 in the left-right direction of the cam shaft 70 (in the present embodiment, immediately to the left of the second guide groove 72). The first detection row 73 includes a first reverse recess 73a and a first low speed recess 73b. The first reverse recess 73a and the first low speed recess 73b are formed in a shape extending long in the left-right direction so as to be recessed in a part of the outer peripheral surface of the cam shaft 70. The first reverse recess 73a is formed at a position facing the first sensor 80 in a state in which the transmission speed of the transmission 8 is switched to the reverse speed R. The first low-speed recess 73 b is formed at a position facing the first sensor 80 in a state where the gear position of the transmission 8 is switched to the low-speed stage L.

  The second detection row 74 is formed at a position facing the second sensor 90 in the left-right direction of the cam shaft 70 (between the first guide groove 71 and the first detection row 73 in the present embodiment). The second detection row 74 includes a second high speed recess 74a and a second low speed recess 74b. The second high speed recess 74a and the second low speed recess 74b are formed in a shape extending long in the left-right direction so that a part of the outer peripheral surface of the cam shaft 70 is recessed. The second high speed recess 74 a is formed at a position facing the second sensor 90 in a state where the gear position of the transmission 8 is switched to the high speed stage H. The second low speed recess 74 b is formed at a position facing the second sensor 90 in a state where the transmission speed of the transmission 8 is switched to the low speed L.

  The neutral detection recessed part 75 is formed so that a part of outer peripheral surface of the cam shaft 70 may be recessed. The neutral detection recess 75 is formed at a position immediately to the left of the first guide groove 71 in the left-right direction of the camshaft 70 and facing the neutral sensor 100 in a state where the transmission speed of the transmission 8 is switched to the neutral speed N. The

  A liquid crystal display unit 301 shown in FIG. 9 is an embodiment of a notifying unit according to the present invention, and is for notifying a pilot of information related to the multipurpose work vehicle 1. The liquid crystal display unit 301 is formed in a substantially rectangular shape, and is disposed in the vicinity of the steering wheel 5a of the riding part 5 (see FIG. 1).

  The ECU 302 is a control device that manages information about the multipurpose work vehicle 1 and controls the operation of the connected equipment. The ECU 302 includes a storage unit, an arithmetic processing unit, and the like. The ECU 302 stores a program for controlling each device of the multipurpose work vehicle 1 and various data.

The ECU 302 is connected to the first sensor 80 and the second sensor 90 and can receive signals related to detection by the first sensor 80 and the second sensor 90.
The ECU 302 is connected to the liquid crystal display unit 301 and can display an arbitrary upper part on the liquid crystal display unit 301.
The ECU 302 is connected to the engine 6 (more specifically, a fuel injection device or the like of the engine 6), and can control the rotational speed of the engine 6.

  In the shift position detection mechanism 300 configured as described above, the first sensor 80 corresponds to the first detection row 73, and the second sensor 90 corresponds to the second detection row 74. Thus, the gear position detection mechanism 300 according to the present embodiment has two sets of detection rows and corresponding sensors.

  In such a configuration, the first sensor 80 can detect the first reverse recess 73 a and the first low speed recess 73 b of the first detection row 73. Specifically, when the gear position of the transmission 8 is switched to the reverse gear R or the low gear L, the first reverse recess 73a or the first low speed recess 73b faces the first sensor 80 (FIG. 12 (a) or (Refer FIG.13 (b)). In this state, the detection end 81 of the first sensor 80 does not interfere (contact) with the camshaft 70 and is extended to the maximum extent in the first reverse recess 73a or the first low speed recess 73b (OFF state). )

  On the other hand, the first sensor 80 detects the first reverse recess 73a and the first low speed recess 73b when the gear position of the transmission 8 is switched to other than the reverse gear R or the low gear L (that is, the neutral gear N or the high gear H). (Refer to FIG. 12B or FIG. 13A). In this state, the detection end portion 81 of the first sensor 80 comes into contact with the outer peripheral surface of the cam shaft 70 and is in a state where it is compressed by a predetermined amount (ON state).

  Therefore, when the first sensor 80 detects that the transmission is in the OFF state, the first reverse recess 73a is switched to the low speed stage L when the transmission stage of the transmission 8 is switched to the reverse stage R. The first low-speed recess 73b can be detected respectively.

  Similarly, when the second sensor 90 is switched to the high speed stage H, the second high speed recess 74a (see FIG. 13 (a)), and when the transmission stage of the transmission 8 is switched to the low speed stage L, the second sensor 90 is switched. The second low-speed recess 74b (see FIG. 13B) can be detected respectively.

  Similarly, the neutral sensor 100 can detect the neutral detection recess 75 when the transmission gear of the transmission 8 is switched to the neutral gear N (see FIG. 13B). Further, when the neutral sensor 100 does not detect the neutral detection recess 75, that is, when the gear position of the transmission 8 is other than the neutral gear N, the engine start circuit 6a is not activated by the signal from the neutral sensor 100. It is restrained by. As a result, no current is supplied to the starter motor for starting the engine 6, and the engine 6 cannot be started. In this way, the engine 6 can be started only when the gear position of the transmission 8 is the neutral stage N.

  Next, with reference to FIGS. 9 and 11, a description will be given of how the gear position of the transmission 8 is detected by the gear position detection mechanism 300 configured as described above.

As described above, signals related to detection by the first sensor 80 and the second sensor 90 are transmitted to the ECU 302. When the ECU 302 receives a detection signal from the first sensor 80 (second sensor 90), the detection end 81 (detection end 91) is in an ON state, that is, the first sensor 80 (second sensor 90). Determines that the concave portion of the camshaft 70 is not detected.
On the other hand, when the ECU 302 has not received the detection signal from the first sensor 80 (second sensor 90), the detection end 81 (detection end 91) is in an OFF state, that is, the first sensor 80 (first sensor 80). The second sensor 90) determines that the concave portion of the camshaft 70 is detected.

  In the table in FIG. 11, the case where the ECU 302 determines that the first sensor 80 and the second sensor 90 have detected the concave portion of the camshaft 70 is indicated by a circle.

As shown in FIG. 11, the ECU 302 determines that only the first sensor 80 has detected the recess when the gear position of the transmission 8 is the reverse gear R.
Further, the ECU 302 determines that neither the first sensor 80 nor the second sensor 90 has detected a recess when the gear stage of the transmission 8 is the neutral stage N.
Further, the ECU 302 determines that only the second sensor 90 has detected the recess when the gear position of the transmission 8 is the high speed stage H.
Further, the ECU 302 determines that both of the first sensor 80 and the second sensor 90 have detected the recess when the gear position of the transmission 8 is the low speed stage L.

  Thus, there are four patterns of combinations of detection results from the first sensor 80 and the second sensor 90 in accordance with the four gear positions of the transmission 8. Therefore, the ECU 302 stores the combinations of the detection results of the four patterns and the corresponding gear positions of the transmission 8 in advance, so that the transmission 8 is based on the detection signals from the first sensor 80 and the second sensor 90. Can be detected.

That is, the ECU 302 can detect that the gear position of the transmission 8 is the reverse gear R when only the first sensor 80 detects the recess.
Further, the ECU 302 can detect that the gear position of the transmission 8 is the neutral stage N when neither the first sensor 80 nor the second sensor 90 has detected a recess.
Further, the ECU 302 can detect that the gear position of the transmission 8 is the high speed gear H when only the second sensor 90 detects the recess.
Further, the ECU 302 can detect that the gear position of the transmission 8 is the low gear L when both the first sensor 80 and the second sensor 90 detect the recess.

  Further, as shown in FIG. 9, the ECU 302 causes the liquid crystal display unit 301 to display the detected gear position of the transmission 8. For example, the ECU 302 sets “N” when the transmission 8 is in the neutral stage N, “H” when the transmission is at the high speed H, “L” when the transmission is at the low speed L, and the reverse speed R. In some cases, “R” or the like is displayed. Thereby, the operator of the riding section 5 can be notified of the current gear position of the transmission 8, and the operability (ease of maneuverability) of the multipurpose work vehicle 1 can be improved.

  Further, when the detected gear position of the transmission 8 is the reverse speed R, the ECU 302 controls the operation of the engine 6 to reduce the rotational speed of the engine 6. As a result, the traveling speed when the multipurpose work vehicle 1 moves backward is reduced, and the operability when the multipurpose work vehicle 1 moves backward can be improved.

  In the present embodiment, the ECU 302 detects that the gear position of the transmission 8 is the neutral stage N when neither the first sensor 80 nor the second sensor 90 has detected a recess. Therefore, while the gear stage of the transmission 8 is being switched between the neutral stage N and the reverse stage R, while being switched between the neutral stage N and the high speed stage H, and between the high speed stage H and the low speed stage. Even during switching between the gears L, neither the first sensor 80 nor the second sensor 90 detects the recess, so that the gear is detected as the neutral gear N.

  As described above, when neither the first sensor 80 nor the second sensor 90 has detected the recess, the configuration is such that the neutral stage N is detected, so that the transmission stage of the transmission 8 is being switched. Can be detected as a neutral stage N. While the gears are being switched as described above, the gears of the transmission 8 are not switched to any of the reverse gear R, the high speed gear H, and the low speed gear L, and in effect the neutral gear N. Is the same state.

As described above, the gear position detection mechanism 300 according to the present embodiment is
A transmission that changes the gear position by switching the positions of the first shift fork 61 and the second shift fork 62 (shift fork) interlocked with the cam shaft 70 by rotating the cam shaft 70 (transmission operation shaft) about the axis. 8 (shift mechanism), a shift position detecting mechanism 300 for detecting the position of the shift stage,
A first detection row 73 and a second detection row 74 (detection row) in which concave portions (recess portions or convex portions) are formed at predetermined intervals in the circumferential direction on the outer peripheral surface of the cam shaft 70;
A first sensor 80 and a second sensor 90 (detection means) provided corresponding to the detection row and arranged to face the detection row and detecting whether or not the concave portion is at a position facing the detection row. When,
Comprising
The detection row and the detection means corresponding to the detection row have two sets (multiple sets),
The shift position is detected based on a combination of detection results from each of the plurality of detection means.

  With this configuration, a large number of shift speed positions (reverse speed R, neutral speed N, high speed speed H and low speed speed L) can be detected with a small number of detection means (first sensor 80 and second sensor 90). This can reduce the cost of parts. Further, since it is sufficient for the detection means to be able to detect only the presence or absence of the recess, the detection means is inexpensive (for example, a contact type that can detect only the ON state or the OFF state as in the present embodiment). Sensor), and the cost of parts can be further reduced. Further, since the detecting means need not be adjusted (or simple) when it is attached, the assembling cost can be reduced.

The camshaft 70 is
The transmission 8 is accommodated in a transmission case 8a (transmission case) in which the transmission 8 is accommodated.

  With this configuration, the camshaft 70 for detecting the position of the gear position can be protected. Further, when the detecting means is in direct contact with the camshaft 70, the contacting portion can be lubricated by the lubricating oil stored in the transmission case 8a, and the durability of the gear position detecting mechanism 300 is improved. Can do.

The camshaft 70 has a
A first guide groove 71 and a second guide groove 72 (guide groove) for guiding the shift fork to a predetermined position are formed;
The shift fork is
It is engaged with the guide groove.

  With this configuration, the concave portion is formed in the member (transmission operation shaft) that switches the position of the shift fork directly, and the concave portion is detected, so that play between the members gives the detection result. The influence can be suppressed small, and the error between the actual gear position and the detected gear position can be reduced.

In addition, the concave portion or the convex portion is
This is a concave portion in which a part of the outer peripheral surface of the cam shaft 70 is recessed.

  By comprising in this way, the process for forming an uneven | corrugated | grooved part (concave part) becomes easy.

Further, the transmission 8 has four speed stages,
Two sets of the detection row and the detection means are provided,
The four gear positions are detected based on a combination of detection results from the two detection means.

  With this configuration, it is possible to provide a gear position detection mechanism 300 that is optimal for detecting four gear positions.

Moreover, the multipurpose work vehicle 1 (work vehicle) according to the present embodiment is
A multi-purpose work vehicle 1 including a gear position detection mechanism 300,
The transmission 8 has, as the shift stages, a high speed stage H for moving the multipurpose work vehicle 1 at a high speed, a low speed stage L for moving the multipurpose work vehicle 1 at a low speed, a reverse speed R for moving the multipurpose work vehicle 1 backward, and the multipurpose work vehicle 1. The vehicle has a neutral stage N that does not run the vehicle.

  With this configuration, it is possible to detect the gear position of the multipurpose work vehicle 1.

Further, the gear position detection mechanism 300 is
It further includes a liquid crystal display 301 (notification means) for notifying the operator of the detected gear position.

  With this configuration, the detected gear position can be notified to the operator, and the operability of the multipurpose work vehicle 1 can be improved.

In the present embodiment, a so-called detent mechanism (see FIG. 6 and the like) is configured by the cam plate 77, the cam rod 120, and the like, but the configuration of the detent mechanism is not limited to this. For example, a configuration as shown in FIG. 14 may be used.
Specifically, in place of the cam plate 77, a substantially circular plate 78 in which a plurality of through holes 78a, 78a,. The through holes 78a, 78a,... Are formed at positions (intervals) corresponding to the gear position of the transmission 8. From the side of the plate 78, a sphere 79 having a diameter that is slightly larger than the diameter of the through hole 78a is pressed against the through hole 78a by the biasing force of the spring 79a. Thereby, a part of the sphere 79 is fitted in the through hole 78a, and a clear operational feeling can be obtained when switching to each gear stage.

  Further, in the present embodiment, as an embodiment of the speed change operation shaft (a member on which the detection row is formed) according to the present invention, the cam shaft 70 formed with the guide groove for guiding the shift fork is illustrated. The present invention is not limited to this. That is, it is also possible to adopt a configuration in which a detection row is formed on another shaft-like member that rotates in conjunction with the cam shaft 70 (for example, the operation rod 110 according to the present embodiment). The speed change operation shaft on which the detection row is formed may be provided outside the transmission case 8a.

  In the present embodiment, the camshaft 70 switches the positions of the two shift forks. However, the present invention is not limited to this, and the number of shift forks for switching the position may be one or three or more. good.

  Further, in the present embodiment, the detection row is configured by forming a recess, but the present invention is not limited to this. That is, it is possible to form a convex portion in place of the concave portion and detect the convex portion with the detecting means (first sensor 80 and second sensor 90).

  In the present embodiment, a sensor (a first sensor 80 and a second sensor 90) that can detect a concave portion by abutting the detection end portion directly on the camshaft 70 as a detection means and expanding and contracting the detection end portion. However, the present invention is not limited to this. That is, the detection means may be any means that can detect the presence or absence of irregularities on the cam shaft 70.

  In the present embodiment, the gear position detection mechanism 300 includes a detection row (first detection row 73 and second detection row 74) and detection means (first sensor 80 and second sensor) corresponding to the detection row. 90) and 2 sets. However, the present invention is not limited to this, and may include 3 sets or more. As a result, it is possible to detect more gears.

  In the present embodiment, the detection row is formed between the first guide groove 71 and the second guide groove 72 of the camshaft 70. However, the present invention is not limited to this, and any detection row may be used. It is possible to form in position. For example, the detection rows can be formed at one end of the camshaft 70 or at both ends. Similarly, the detection means can also be provided at an arbitrary position as long as it can detect the concave portion of the detection row.

  In the present embodiment, the ECU 302 detects the position of the gear position of the transmission 8 based on the combination pattern of the detection results obtained by the first sensor 80 and the second sensor 90 shown in FIG. The invention does not limit this pattern. That is, the pattern can be arbitrarily set as long as the position of each shift stage can be detected separately. In this case, an appropriate pattern is stored in advance in the ECU 302 based on the position of each recess in the cam shaft 70 set arbitrarily and the positions of the first sensor 80 and the second sensor 90.

  Further, in the present embodiment, the position of the gear position of the transmission 8 is notified to the operator using the liquid crystal display unit 301, but the present invention is not limited to this, and the notification is made by various methods. Is possible. For example, a configuration in which notification is given by voice, a lamp, or the like may be used.

  In the present embodiment, the ECU 302 determines (detects) the position of the gear position of the transmission 8 based on the detection signals from the detection means (the first sensor 80 and the second sensor 90). The invention is not limited to this. For example, without using the ECU 302, it is possible to determine the position of the gear position of the transmission 8 using an electric circuit and notify the determination result by the notification means (the liquid crystal display unit 301 or the like).

  In the present embodiment, the ECU 302 reduces the rotational speed of the engine 6 when the detected gear position of the transmission 8 is the reverse gear R. However, the present invention is not limited to this. That is, the ECU 302 can be configured to perform various controls so as to arbitrarily change the characteristics of the engine 6 in accordance with each detected gear position of the transmission 8.

  In addition, although the multipurpose work vehicle 1 according to the present embodiment includes the CVT 7 as the main transmission, the present invention is not limited to this. That is, a configuration including an HST (hydrostatic continuously variable transmission) instead of the CVT 7 or a configuration not including the main transmission (a configuration in which only the transmission 8 is shifted) may be employed. In addition, the power from the engine 6 is transmitted to the transmission 8 after being shifted by the CVT 7, but the present invention is not limited to this, and is configured to be transmitted to the CVT 7 after being shifted by the transmission 8. May be.

  Next, the gear position detection mechanism 300 according to the second embodiment will be described below.

  As shown in FIG. 15, in the shift position detection mechanism 300 according to the second embodiment, not only the detection signals from the first sensor 80 and the second sensor 90 but also the detection signal from the neutral sensor 100, The position of the gear position is detected. For this reason, in the gear position detection mechanism 300 according to the second embodiment, although not shown, the neutral sensor 100 is also connected to the ECU 302.

In such a configuration, the ECU 302 can detect that the shift speed of the transmission 8 is the reverse speed R when only the first sensor 80 detects the recess.
Further, when only the neutral sensor 100 detects the recess, the ECU 302 can detect that the gear position of the transmission 8 is the neutral stage N.
Further, the ECU 302 can detect that the gear position of the transmission 8 is the high speed gear H when only the second sensor 90 detects the recess.
Further, the ECU 302 can detect that the gear stage of the transmission 8 is the neutral stage N when both the first sensor 80 and the second sensor 90 detect the recess.

Further, in the gear position detection mechanism 300 according to the second embodiment, unlike the first embodiment, the neutral sensor 100 even if neither the first sensor 80 nor the second sensor 90 has detected a recess. ECU 302 does not detect that the shift stage is the neutral stage N unless the depression is detected.
Therefore, in the gear position detection mechanism 300 according to the second embodiment, the gear 8 of the transmission 8 is switched between the neutral gear N and the reverse gear R while the gear 8 is switched between the neutral gear N and the high gear H. , And during switching between the high speed stage H and the low speed stage L (that is, any of the first sensor 80, the second sensor 90, and the neutral sensor 100 detects the recess). In this state, it is possible to prevent the ECU 302 from detecting that the shift stage is the neutral stage N.

  Next, the gear position detection mechanism 300 according to the third embodiment will be described below.

  As shown in FIG. 16, in the gear position detection mechanism 300 according to the third embodiment, the cam shaft 70 includes a second high speed recess 74a and a second low speed recess 74b according to the first embodiment (see FIG. 11 and the like). Instead, a second high / low speed recess 74c is formed. The second high / low speed recess 74c is one large recess formed so as to connect the second high speed recess 74a and the second low speed recess 74b according to the first embodiment.

  With this configuration, in the gear position detection mechanism 300 according to the third embodiment, unlike the first embodiment, the gear position of the transmission 8 is switched between the high speed stage H and the low speed stage L. Even in the middle, the second sensor 90 remains in a state where the recess (second high / low speed recess 74c) is detected (that is, the ECU 302 remains in a state where the gear stage of the transmission 8 is detected as the high speed stage H). . Accordingly, it is possible to prevent the ECU 302 from detecting that the shift stage is the neutral stage N while the shift stage of the transmission 8 is being switched between the high speed stage H and the low speed stage L.

  Note that, as in the third embodiment, it is possible to accurately detect that the shift stage of the transmission 8 is the neutral stage N using the first sensor 80 and the second sensor 90 (the high speed stage H and the low speed stage). In the case of a configuration in which it is possible to prevent the shift speed from being detected as the neutral speed N while being switched between the first sensor 80 and the neutral sensor 100, By using the second sensor 90, the neutral sensor 100 can be abolished (reduced).

1 Multipurpose work vehicle (work vehicle)
8 Transmission (transmission mechanism)
8a Transmission case (shift case)
61 First shift fork (shift fork)
62 Second shift fork (shift fork)
70 Cam shaft (speed change operation shaft)
71 First guide groove (guide groove)
72 Second guide groove (guide groove)
73 First detection row (detection row)
73a First reverse recess (recess)
73b First low speed recess (recess)
74 Second detection row (detection row)
74a Second high speed recess (recess)
74b Second low speed recess (recess)
80 First sensor (detection means)
90 Second sensor (detection means)
300 gear position detection mechanism 301 liquid crystal display (notification means)

Claims (5)

A gear position detecting mechanism for detecting the position of the gear position, wherein the gear position is changed by changing the gear position by switching the position of the shift fork interlocked with the gear shift operation shaft by rotating the gear shaft. There,
A detection row in which concave portions or convex portions are formed at predetermined intervals in the circumferential direction on the outer peripheral surface of the speed change operation shaft;
Detecting means provided corresponding to the detection row, arranged to face the detection row, and detecting whether or not the concave portion or the convex portion is in a facing position;
Comprising
A plurality of sets of the detection row and the detection means corresponding to the detection row;
The gear position is detected based on a combination of detection results by each of a plurality of detection means,
Gear position detection mechanism. The speed change operation shaft is
The transmission mechanism is stored in a transmission case in which the transmission mechanism is stored.
The gear position detection mechanism according to claim 1. The speed change operation shaft includes
A guide groove for guiding the shift fork to a predetermined position is formed,
The shift fork is
It is engaged with the guide groove,
The gear position detection mechanism according to claim 1 or 2. The concave or convex portion is
It is a recess having a shape in which a part of the outer peripheral surface of the speed change operation shaft is recessed,
The gear position detection mechanism according to any one of claims 1 to 3. The speed change mechanism has four speed stages.
Two sets of the detection row and the detection means are provided,
Based on a combination of detection results by each of the two detection means, the four speed positions are detected.
The gear position detection mechanism according to any one of claims 1 to 4.

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