JP5665600B2 - Tractor - Google Patents

Description

  The present invention relates to a tractor including a continuously variable transmission and a speed change operation tool capable of performing a speed change operation on an output of the continuously variable transmission.

  2. Description of the Related Art Conventionally, a tractor that travels by transmitting engine power to wheels via a continuously variable transmission is known (see, for example, Patent Document 1). The tractor described in Patent Document 1 is provided with a forward shift pedal and a reverse shift pedal, and these forward shift pedal and reverse shift pedal are connected to an adjustment member that changes the output of HST via an HST operation link, A forward travel is performed by operating the forward shift pedal, and a reverse travel is performed by operating the reverse shift pedal.

JP 2007-55281 A

  Since the tractor shown in Patent Document 1 has two shift pedals, a forward shift pedal and a reverse shift pedal, it is necessary to change each pedal when moving forward or backward, and an operator unaccustomed to operating the tractor. In this case, the operation could not be performed like a passenger car, and the operation was confused.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a tractor with good operability.

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

According to the first aspect of the present invention, a shift pedal that can be shifted from the neutral position to the highest speed position, a forward / reverse switching lever that can be switched to the forward position, the reverse position, and the neutral position, and a reverse speed from the forward speed by operating the speed changing means. A tractor comprising: a continuously variable transmission capable of shifting to a speed; and a forward / reverse switching mechanism linked to the speed change pedal, the forward / reverse switching lever, and a speed changing means of the continuously variable transmission. The advance switching mechanism has a cylindrical main body and a rotary shaft protruding radially from the outer surface of the main body, and the rotary base of the shift pedal is fixed to the rotary shaft. Forward / reverse switching having a support, a cylindrical body that is rotatably supported along the inner surface of the main body of the rotary support, and an operation arm that protrudes outward from the rotary support from one end of the cylindrical body Body and first on the operating arm A link member linked to the speed changing means of the continuously variable transmission through a joint, a shaft fixed to the axial center of the cylindrical body, and a second universal joint connected to the shaft. And a forward / reverse switching arm connected to the forward / reverse switching lever via a connecting means, and a holding mechanism for holding the forward / reverse switching arm at the forward position, the reverse position, and the neutral position.

According to a second aspect of the present invention, the holding mechanism supports a pressing member attached to the forward / reverse switching arm and a support shaft of the forward / backward switching arm, and is a position facing the pressing member, the supporting shaft And a support member having an engagement portion arranged at a predetermined interval on a concentric circle centering on the center.

  According to the present invention, a shift operation and a forward / reverse switching operation can be performed with one pedal and one lever. Therefore, it can drive | operate like a passenger car and operability improves.

The side view which shows the whole structure of the tractor 1. FIG. The left front perspective view showing the forward / reverse switching mechanism 20. FIG. 6 is a left rear perspective view showing the forward / reverse switching mechanism 20. (A) The side view which shows the forward / reverse switching mechanism 20. (B) A bottom view showing the forward / reverse switching mechanism 20. (A) The front view which shows the forward / reverse switching mechanism 20. FIG. (B) A rear view showing the forward / reverse switching mechanism 20. FIG. 4 is a side view showing the operation of the forward / reverse switching mechanism 20. (A) The forward / reverse switching lever 11 is “neutral position”, and the shift pedal 10 is “neutral position”. (B) The forward / reverse switching lever 11 is in the “neutral position” and the shift pedal 10 is in the “highest speed position”. FIG. 4 is a side view showing the operation of the forward / reverse switching mechanism 20. (A) The forward / reverse switching lever 11 is “forward position”, and the shift pedal 10 is “neutral position”. (B) The forward / reverse switching lever 11 is “forward position”, and the shift pedal 10 is “highest speed position”. FIG. 4 is a side view showing the operation of the forward / reverse switching mechanism 20. (A) The forward / reverse switching lever 11 is “reverse position” and the shift pedal 10 is “neutral position”. (B) The forward / reverse switching lever 11 is “reverse position” and the shift pedal 10 is “highest speed position”. The perspective view which shows the other forward / reverse switching mechanism 120. FIG. Sectional drawing which shows the other forward / reverse switching mechanism 120. FIG. Sectional drawing which shows the structure of the belt-type continuously variable transmission 80. FIG.

  Below, the whole structure of the tractor 1 which is one Embodiment of the tractor which concerns on this invention is demonstrated using FIG. In the following description, the arrow F is defined as the forward direction, the arrow B as the backward direction, the arrow L as the left direction, the arrow R as the right direction, the arrow U as the upward direction, and the arrow D as the downward direction.

  As shown in FIG. 1, in the tractor 1, a pair of left and right body frames 2, 2 are arranged at a predetermined interval in the left-right direction with the longitudinal direction being the front-rear direction, and left and right through the front axle case at the front part. It is supported by a pair of front wheels 3 and 3, and is supported by a pair of left and right rear wheels 4 and 4 via a rear axle case at the rear part.

  An engine 5 is mounted on the front part of the body frame 2, 2, and a transmission case 7 for housing the continuously variable transmission is provided on the rear part, and rear axle cases are provided on both sides of the rear part of the transmission case 7. It is done. A driving operation unit 8 is disposed in the front and rear halfway and rear of the machine body frame 2. 2, and a steering handle 9, a shift pedal 10, a forward / reverse switching lever 11, and the like are provided in the driving operation unit 8. Specifically, the forward / reverse switching lever 11 is disposed so as to protrude from the left side of the handle column supporting the handle shaft of the steering handle 9 to the side. The speed change pedal 10 is disposed on the front and rear halfway of the body frames 2 and 2 and is disposed on the right side of the step.

  The steering handle 9 is configured so that the tractor 1 can be steered by changing the steering angle of the pair of left and right front wheels 3 and 3 according to the amount of rotation operation. The shift pedal 10 is configured to be able to be depressed from a “neutral position” to a “highest speed position”, and can adjust the traveling speed of the tractor 1 according to the operation amount. The forward / reverse switching lever 11 is configured to be pivotable in the front-rear direction, and is operated to the “forward position” when rotated forward from the “neutral position”, and “reverse” when rotated backward from the “neutral position”. It is operated to “position”. In this way, the traveling direction of the tractor 1 can be switched in accordance with the operation in the front-rear direction of the forward-reverse switching lever 11.

  A work machine mounting device 12 is provided at the rear of the mission case 7. The work machine mounting device 12 mainly includes a top link 12a, lower links 12b and 12b, lift rods 12c and 12c, and lift arms 12d and 12d. The lift rods 12c and 12c have lower links 12b and 12c at one end. The other end is connected to lift arms 12d and 12d protruding rearward from the hydraulic case. A working machine such as a rotary tiller (not shown) is connected to the rear ends of the top link 12a and the lower links 12b and 12b.

  Then, after the power of the engine 5 is shifted by the continuously variable transmission in the transmission case 7, it is transmitted to the pair of left and right front wheels 3, 3 and the pair of left and right rear wheels 4, 4 and is driven to rotate. Is done. Further, after the power of the engine 5 is shifted by the PTO transmission, it can be transmitted to the work machine.

  Hereinafter, the continuously variable transmission accommodated in the mission case 7 will be described with reference to FIG.

  The continuously variable transmission according to this embodiment includes a belt type continuously variable transmission 80. The belt type continuously variable transmission 80 includes a transmission input shaft 81, an input pulley 82, a hydraulic cylinder 83, a hydraulic servo mechanism 84, a transmission shaft 85, an output pulley 86, an output member 87, a cam mechanism 88, a biasing member 89, and a belt 90. And a planetary gear mechanism 91 and the like.

  The power of the engine 5 can be transmitted to the transmission input shaft 81. An input pulley 82 is provided in the middle of the transmission input shaft 81. The input pulley 82 includes a fixed sheave 82a that is fixed to the speed change input shaft 81 so as not to be relatively rotatable and slidable, and a movable sheave 82b that is supported to be slidable relative to the speed change input shaft 81.

  The hydraulic cylinder 83 slides the movable sheave 82b of the input pulley 82 in the front-rear direction, and changes the distance between the movable sheave 82b and the fixed sheave 82a. The hydraulic cylinder 83 is provided at the front portion of the movable sheave 82b.

  The hydraulic servo mechanism 84 controls the operation of the hydraulic cylinder 83. The hydraulic servo mechanism 84 includes the front case 14, the servo spool 6, a feedback spool 84a, and the like.

  An oil passage through which hydraulic oil flows is appropriately formed in the front case 14. The servo spool 6 is slidably provided in the front case 14. The servo spool 6 is a speed changing means, and is interlocked and connected to the speed change pedal 10 via a forward / reverse switching mechanism 20 described later, so that the hydraulic oil is slid in the front / rear direction by the speed change pedal 10. The operation of the hydraulic cylinder 83 can be controlled by switching the oil passage through which the hydraulic oil is supplied and the hydraulic oil is supplied to the hydraulic cylinder 83 or discharged from the hydraulic cylinder 83. A feedback spool 84a is slidably provided in the servo spool 6. The rear end of the feedback spool 84 a is in contact with the hydraulic cylinder 83, and the hydraulic fluid supplied to the hydraulic cylinder 83 can be controlled by switching the oil path according to the operating position of the hydraulic cylinder 83.

  The transmission shaft 85 is disposed in parallel with the transmission input shaft 81. An output pulley 86 is provided in the vicinity of the front end portion of the transmission shaft 85. The output pulley 86 includes a fixed sheave 86a that is fixed to the transmission shaft 85 so as not to rotate relative to the transmission shaft, and a movable sheave 86b supported relative to the transmission shaft 85 so as not to rotate relative to the transmission shaft 85.

  The output member 87 is disposed in a state of being inserted by the transmission shaft 85 behind the output pulley 86. A cam mechanism 88 including a pair of front and rear cam members facing each other is provided between the output pulley 86 and the output member 87. The cam member of the cam mechanism 88 is fixed to the movable sheave 86b and the output member 87 of the output pulley 86, respectively. A biasing member 89 is disposed between the movable sheave 86 b and the output member 87, and the movable sheave 86 b is biased forward by the biasing force of the biasing member 89.

  A belt 90 is wound between the input pulley 82 and the output pulley 86. Power is transmitted between the input pulley 82 and the output pulley 86 via the belt 90.

  A planetary gear mechanism 91 is provided behind the output member 87. The planetary gear mechanism 91 is connected to the output member 87, the transmission input gear 81a, and the output shaft 92. Then, the power from the output member 87 and the power from the speed change input gear 81 a are once combined and then output to the output shaft 92.

  In the belt type continuously variable transmission 80 configured as described above, the power of the transmission input shaft 81 is transmitted to the output pulley 86 via the input pulley 82 and the belt 90. The power transmitted to the output pulley 86 is transmitted to the planetary gear mechanism 91 via the cam mechanism 88 and the output member 87. The power of the transmission input shaft 81 is also transmitted to the planetary gear mechanism 91 from the transmission input gear 81a. The two powers transmitted to the planetary gear mechanism 91 are combined in the planetary gear mechanism 91 and then transmitted to the output shaft 92. The power transmitted to the output shaft 92 is transmitted to the rear wheels 4 and 4 via the rear axle case. The power transmitted to the output shaft 92 is transmitted from the front wheel drive transmission shaft 93 to the front wheels 4 and 4 through the front axle case.

  Further, the width of the input pulley 82 (the distance between the fixed sheave 82a and the movable sheave 82b) is controlled by sliding the servo spool 6 of the hydraulic servo mechanism 84 in the front-rear direction and controlling the operation of the hydraulic cylinder 83. Can be changed. As a result, the gear ratio when power is transmitted from the input pulley 82 to the output pulley 86 can be arbitrarily changed, and as a result, the power transmitted to the output shaft 92 and the front wheel drive transmission shaft 93 can be arbitrarily changed (speed change). )can do. In this way, the tractor 1 can be steplessly shifted from the forward speed to the reverse speed.

  The continuously variable transmission of the present embodiment is a belt-type continuously variable transmission 80, which is configured by an HST (hydraulic continuously variable transmission) or HMT (hydraulic mechanical continuously variable transmission). It is also possible to change the tractor 1 from a forward speed to a reverse speed by changing the angle of the movable swash plate of the hydraulic pump or hydraulic motor constituting the HST or HMT. In this case, a member such as a speed change arm that is interlocked and connected to the movable swash plate and can change the angle of the movable swash plate by operating becomes a speed changing means of the continuously variable transmission.

  Hereinafter, the forward / reverse switching mechanism 20 which is a main part of the present invention will be described.

  As shown in FIGS. 1 and 2, the forward / reverse switching mechanism 20 is provided between a connecting mechanism that interlocks and connects the shift pedal 10 and a servo spool 6 that serves as a speed changing unit of the continuously variable transmission. . In the present embodiment, the forward / reverse switching mechanism 20 is attached to the inner side surface of the right body frame 2 on the right side of the front end portion of the mission case 7.

  Next, a specific configuration of the forward / reverse switching mechanism 20 will be described. As shown in FIGS. 2 and 3, the forward / reverse switching mechanism 20 includes a rotation support body 21, a forward / reverse switching body 22, a link member 23, a shaft body 24, a forward / backward switching arm 25, and a holding mechanism. 70, and is attached to the inner side surface of the right body frame 2 via the attachment plate 26. That is, the mounting plate 26 is configured to be detachable from the body frame 2 so that the forward / reverse switching mechanism 20 can be easily assembled to the body frame 2 as a unit.

  As shown in FIGS. 3 and 5A, the rotation support body 21 includes a main body 21a, a rotation shaft 21b, and an extending arm 21c. The main body 21 a is configured in a cylindrical shape and is disposed on the left side of the mounting plate 26. The rotating shaft 21b protrudes to the right in the radial direction from the outer surface of the main body 21a, and is rotatable to the right and left horizontal frames via a support boss 43 fixed to the mounting plate 26 on the right body frame 2. Supported. The axis of the main body 21a is arranged in a substantially front-rear direction, and the axis of the rotating shaft 21b is arranged in the orthogonal direction with respect to the axis of the main body 21a. The rotation base 10a of the shift pedal 10 is fixed to one end (right end) of the rotation shaft 21b (see FIG. 1). The extension arm 21c extends vertically above the outer surface of the main body 21a in the radial direction and perpendicular to the rotation shaft 21b. A through hole is formed in the extending arm 21c, and a connecting shaft 27 is inserted into the through hole, and the rear end of the damper 28 is attached. The front end of the damper 28 is in front of the mounting plate 26 and is mounted on the body frame. 2 is pivotably latched on a latch stay 44 attached to 2.

  As shown in FIGS. 3 and 4A, a columnar member 29 protrudes from the rear upper part of the mounting plate 26, and the urging member 30 is connected to the columnar member 29 and the connecting shaft 27. Both ends are respectively latched, and the rotation support body 21 is urged clockwise in FIG. 4A with respect to the mounting plate 26 (that is, the machine body frame 2). A rear plate 31 extends to the upper left at the rear portion of the mounting plate 26, and a bolt 32 is screwed to the rear plate 31 at a position facing the outer peripheral surface of the connecting shaft 27. The tip of the bolt 32 is in contact with the outer peripheral surface of the connecting shaft 27 when the shift pedal 10 is not depressed (in a neutral state). That is, the bolt 32 serves as a stopper.

  In this way, even if the speed change pedal 10 is suddenly depressed, the rotation support body 21 is prevented from suddenly starting without the servo spool 6 being operated suddenly because the rotation speed is restricted by the damper 28. Even if the foot is suddenly released from the position where the speed change pedal 10 is stepped on, the rotation support 21 tries to rotate in the opposite direction by the urging force of the urging member 30, but is rotated by the damper 28. The speed is regulated (buffered) to prevent sudden deceleration. In addition, the neutral position of the rotation support body 21 can be changed by adjusting the position of the bolt 32 with respect to the rear plate 31.

  As shown in FIGS. 3 and 5A, the forward / reverse switching body 22 includes a cylindrical body 22a and an operation arm 22b. The cylindrical body 22a is inserted into a shaft hole portion of the main body 21a of the rotation support body 21 via a bearing 42, and is supported rotatably along the inner surface of the main body 21a. Further, the operation arm 22b is projected from one end of the cylindrical body 22a to the outside of the rotation support body 21. A surface perpendicular to the axial center of the cylindrical body 22a is formed at the tip of the operation arm 22b, and a substantially equilateral triangular triangular plate 33 is attached to this surface by two bolts at two vertices. Further, as shown in FIGS. 4 (b) and 5 (b), the apex farthest from the axial center of the cylindrical body 22a, which is the remaining apex of the triangular flat plate 33, is provided via a bearing (not shown). The first shaft member 34 is inserted. That is, the first shaft member 34 is rotatably supported with respect to the forward / reverse switching body 22 including the triangular flat plate 33.

As shown in FIGS. 3 and 4B, the link member 23 is a substantially crank-shaped columnar member, and is disposed behind the triangular flat plate 33 provided on the operation arm 22b. An output side joint 50b constituting the first universal joint 50 is fixed to one end (front end) of the link member 23, and the input side joint 50a corresponding to the output side joint 50b is connected to the rear end of the first shaft member 34. Fixed. That is, the link member 23 is connected to the first shaft member 34 via the first universal joint 50. The rotation fulcrum of the first universal joint 50 is disposed on the extension of the axis of the rotation shaft 21b.

  As shown in FIGS. 2 and 3, the other end (rear end) of the link member 23 is connected to the servo spool 6 of the continuously variable transmission. Specifically, a rod end 35 is fixed to the other end of the link member 23 and a second shaft member 36 is inserted therein. When the forward / reverse switching mechanism 20 is in the neutral position, the connecting portion between the rod end 35 and the second shaft member 36 is disposed on the shaft center extension of the shaft body 24 and the support shaft 39 described later. The second shaft member 36 is connected to a servo spool 6 that is a speed changing means of the continuously variable transmission. In the present embodiment, a servo valve for shifting the continuously variable transmission housed in the mission case 7 is provided at the front portion of the mission case 7, and the servo spool 6 projects forward from the front end of the mission case 7. The An engaging groove 6a is formed in a ring shape on the outer periphery of the front end of the servo spool 6 configured in a rod shape, and the tip of the second shaft member 36 is inserted into and engaged with the engaging groove 6a.

  A midway portion of the second shaft member 36 is inserted into and supported by the engagement hole at the tip (lower part) of the speed change arm 13. The upper portion of the speed change arm 13 is rotatably supported by a support shaft 13 a provided on the front case 14 protruding from the mission case 7. The support shaft 13a is fitted with a base portion of a neutral urging spring 15 composed of a torsion spring, and two tip portions projecting from the neutral urging spring 15 are projected downward in parallel to form two tip portions. A restriction pin 13b protruding from the speed transmission arm 13 and a restriction pin 14a protruding from the front case 14 are inserted between the two parts, and the speed transmission arm 13 is biased neutrally. However, the configuration for biasing the speed change arm 13 to be neutral is not limited.

  As shown in FIGS. 3 and 4B, the shaft body 24 is fitted into the shaft hole portion of the cylindrical body 22a of the forward / reverse switching body 22, and is fixed to the axial center portion of the cylindrical body 22a. An output side joint 60b constituting the second universal joint 60 is fixed to one end (front end) of the shaft body 24, and an input side joint 60a corresponding to the output side joint 60b is disposed in front of the shaft body 24. The support shaft 39 is fixed to the rear end of the support shaft 39. The support shaft 39 is rotatably supported by a cylindrical member 40 that is fixedly inserted into a front plate 37 that is a support member extending leftward from the front portion of the mounting plate 26. That is, since the shaft body 24 is connected to the support shaft 39 via the second universal joint 60, even if the shaft body 24 and the support shaft 39 are not located on the same axis, the support shaft 39 is supported. As a result of the rotation, the shaft body 24 and, consequently, the forward / reverse switching body 22 rotate integrally. When the forward / reverse switching lever 11 is operated to the “neutral position”, the shaft body 24 and the support shaft 39 are coaxially positioned. The pivot point of the second universal joint 60 is disposed on the axial extension of the pivot shaft 21b.

  As shown in FIGS. 2, 3, and 5 (b), the forward / reverse switching arm 25 is an L-shaped flat plate material and is disposed in front of the front plate 37 in parallel with the front plate 37. The bent portion 25 a of the forward / reverse switching arm 25 is fixed at the front end of the support shaft 39, and a cylindrical member 40 is inserted into the front portion of the support shaft 39 so as to be rotatably supported by the front plate 37. One end 25b of the forward / reverse switching arm 25 is connected to the forward / backward switching lever 11 via the connecting means 41, and a pressing member for the holding mechanism 70 is provided at the other end 25c.

  The holding mechanism 70 holds the rotation position of the forward / reverse switching body 22 with respect to the rotation support body 21. Specifically, the forward / reverse switching arm 25 is restricted from rotating with respect to the front plate 37 to hold the forward / reverse switching body 22 at the “forward position”, “neutral position”, and “reverse position”. The holding mechanism 70 includes a pressing member attached to the forward / reverse switching arm 25 and an engaging portion (a recess or a hole) provided in the front plate 37 so as to engage with the pressing member.

  As shown in FIGS. 2 and 4B, the pressing member is provided at the other end 25 c of the forward / reverse switching arm 25. The pressing member includes a cylindrical body 71a inserted into the other end 25c of the forward / reverse switching arm 25, a spherical body 71b housed in the cylindrical body 71a, and an urging force (not shown) that abuts against the spherical body 71b and urges the spherical body 71b. It is comprised with the member and the split pin 71c which is inserted by the cylindrical body 71a and latches the said urging | biasing member.

  As shown in FIG. 2, FIG. 4B and FIG. 5B, the engaging portion is formed on the front plate 37 serving as the support member, and the front plate 37 is opposed to the spherical body 71b of the pressing member. The three concave portions 72a, 72b, 72c are provided at predetermined positions in a concentric manner with the shaft body 24 as the center. Of these three recesses 72 a, 72 b, 72 c, an advance position recess 72 a is disposed on the upper portion of the front plate 37, and a neutral position recess 72 b is disposed on the upper and lower middle portions of the front plate 37. The reverse position recess 72c is arranged, and the three recesses 72a, 72b, 72c are formed to have a diameter slightly smaller than the diameter of the spherical body 72 of the pressing member. The front plate 37 can be provided with more than three recesses. For example, a concentric circle centered on the shaft body 24 is provided between the neutral position recess and the advance position recess. Is also possible.

  FIG. 6A shows an aspect of the forward / reverse switching mechanism 20 when the forward / reverse switching lever 11 is operated to the “neutral position”. That is, in a state where the forward / reverse switching lever 11 is operated to the “neutral position”, the spherical body 71b of the pressing member engages with the neutral position recess 72b of the front plate 37, and the forward / reverse switching body 22 is moved to the “neutral position”. Will be held. At this time, the rotation fulcrum of the first universal joint 50 and the second universal joint 60 is substantially coaxial with the axis of the rotation shaft 21b.

In this state, as shown in FIG. 6B, when the shift pedal 10 is depressed, the rotation shaft 21b rotates according to the depression amount of the shift pedal 10, and the rotation support body 21 and the forward / reverse switching body are rotated. 22 and the first shaft member 34 rotate integrally around the rotation shaft 21b in the direction of the arrow α1. At this time, since the first universal joint 50 is only bent around a pivot point, the link member 23 does not move relative to the depressing of the speed pedal 10. Further, since the second universal joint 60 only bends around the rotation fulcrum, the support shaft 39 does not rotate.

  FIG. 7A shows an aspect of the forward / reverse switching mechanism 20 when the forward / reverse switching lever 11 is operated to the “forward position”. That is, when the forward / reverse switching lever 11 is operated from the “neutral position” to the “forward position”, as shown in FIG. 2, one end 25b of the forward / reverse switching arm 25 is pushed outward via the connecting means 41, As shown in FIG. 5B, the forward / reverse switching arm 25 rotates in the arrow β1 direction. As the forward / reverse switching arm 25 rotates, the support shaft 39 that supports the forward / reverse switching arm 25 rotates as shown in FIG. As the shaft body 24 rotates, the link member 23 rotates together with the forward / reverse switching body 22 around the shaft body 24. By this rotation of the forward / reverse switching arm 25, the sphere 72 of the pressing member provided at the other end 25c of the forward / reverse switching arm 25 is engaged with the forward position recess 72a from the neutral position recess 72b of the front plate 37, The forward / reverse switching body 22 is held at the “forward position”. At this time, the first universal joint 50 is located below the rotation shaft 21b in a side view.

  In this state, as shown in FIG. 7B, when the shift pedal 10 is depressed, the rotation shaft 21b is rotated according to the depression amount of the shift pedal 10, and the rotation support body 21 and the forward / reverse switching body are rotated. 22 and the first shaft member 34 rotate integrally around the rotation shaft 21b in the direction of the arrow α1. At this time, since the first universal joint 50 is located below in the side view with respect to the rotation shaft 21b, the link member 23 moves to the rear side. That is, the second shaft member 36 inserted into the rod end 35 of the link member 23 is rotated in the direction of the arrow γ1 around the support shaft 13a of the speed change arm 13, and at the same time, the servo spool 6 slides backward. Move (see FIG. 2). As the servo spool 6 slides backward, the continuously variable transmission is shifted forward, and the tractor 1 travels forward according to the amount of operation of the shift pedal 10.

  FIG. 8A shows an aspect of the forward / reverse switching mechanism 20 when the forward / reverse switching lever 11 is operated to the “reverse position”. That is, when the forward / reverse switching lever 11 is operated from the “forward position” to the “reverse position”, as shown in FIG. 2, one end 25b of the forward / reverse switching arm 25 is pulled through the connecting means 41, and FIG. As shown in b), the forward / reverse switching arm 25 rotates in the direction of arrow β2. As the forward / reverse switching arm 25 rotates, the support shaft 39 that supports the forward / reverse switching arm 25 rotates, and the shaft body 24 rotates via the second universal joint 60. As a result of this rotation, the link member 23 together with the forward / reverse switching body 22 rotates integrally around the shaft body 24. By this rotation of the forward / reverse switching arm 25, the spherical body 72 of the pressing member provided at the other end 25c of the forward / reverse switching arm 25 is engaged with the reverse position concave portion 72c from the forward position concave portion 72a of the front plate 37, The forward / reverse switching body 22 is held at the “forward position”. At this time, the first universal joint 50 is located above the rotation shaft 21b in a side view.

  From this state, as shown in FIG. 8B, when the shift pedal 10 is depressed, the rotation shaft 21b is rotated according to the depression amount of the shift pedal 10, and the rotation support body 21 and the forward / reverse switching body are rotated. 22 and the first shaft member 34 rotate integrally around the rotation shaft 21b in the direction of the arrow α1. At this time, since the first universal joint 50 is positioned below in the side view with respect to the rotation shaft 21b, the link member 23 moves to the front side. That is, the second shaft member 36 inserted into the rod end 35 of the link member 23 is rotated in the direction of the arrow γ2 around the support shaft 13a of the speed change arm 13, and at the same time, the servo spool 6 slides forward. Move (see FIG. 2). As the servo spool 6 slides forward, the continuously variable transmission is shifted to the reverse side, and the tractor 1 travels backward according to the amount of operation of the shift pedal 10.

  As described above, in the tractor 1 according to an embodiment of the present invention, the shift pedal 10 that can be shifted from the neutral position to the highest speed position, and the forward / reverse switching that can be switched to the forward position, the reverse position, and the neutral position. A belt-type continuously variable transmission 80 capable of shifting from a forward speed to a reverse speed by operating a lever 11 and a servo spool 6 serving as a speed changing means, the shift pedal 10, the forward / reverse switching lever 11, and the belt-type continuously variable. A forward / reverse switching mechanism 20 linked to the servo spool 6 of the transmission 80. The forward / backward switching mechanism 20 includes a cylindrical main body 21a and an outer surface of the main body 21a. A rotation support 21 having a rotation shaft 21b protruding in the radial direction, and a rotation base 21a of the shift pedal 10 being fixed to the rotation shaft 21b, and the rotation support A forward / reverse switching body 22 having a cylindrical body 22a rotatably supported along the inner surface of the main body 1 and an operation arm 22b projecting outward from the rotational support body 21 from one end of the cylindrical body 22a; A link member 23 linked to the operation arm 22b via the first universal joint 50 and the servo spool 6 of the continuously variable transmission, a shaft body 24 fixed to the axial center of the cylindrical body 22a, and the shaft A forward / reverse switching arm 25 connected to the body 24 via a second universal joint 60 and connected to the forward / reverse switching lever 11 via a connecting means 41, and the forward / reverse switching arm 25 are set to a forward position and a reverse position. And a holding mechanism 70 for holding in the neutral position. As a result, a shifting operation and a forward / reverse switching operation can be performed with one pedal and one lever. Therefore, it is not necessary to switch between the forward pedal and the reverse pedal for operation, and the vehicle can be operated like a passenger car, improving operability. Further, since the forward / reverse switching mechanism 20 is disposed outside the mission case 7, maintenance can be easily performed.

  The holding mechanism 70 supports a pressing member attached to the forward / reverse switching arm 25 and a support shaft 39 serving as a rotation shaft of the forward / backward switching arm 25, and is at a position facing the pressing member. And a front plate 37 serving as a support member having recesses 72a, 72b and 72c arranged at predetermined intervals on a concentric circle with the support shaft 39 as the center. Accordingly, the forward / reverse switching arm 25 can be held at the forward movement position, the reverse movement position, and the neutral position with a simple configuration.

  A forward / reverse switching mechanism 120 shown in FIGS. 9 and 10 can also be configured.

  That is, the forward / reverse switching mechanism 120 includes the rotation support body 121, the cam member 122, the forward / reverse switching arm 123, the forward first connecting member 124, the forward second connecting member 125, and the reverse first A connecting member 126, a reverse side second connecting member 127, a rotating plate 128, and an output member 129 are provided, and are attached to the outer side surface of the right body frame 2 via a mounting plate 150, and a forward / reverse switching mechanism 120 is configured as a unit that can be assembled to the body frame 2.

  The rotation support body 121 is a member formed by bending a plate material into a substantially U shape with a substantially rectangular shape in a side view and an upper side opened in a front view, and is disposed on the right side of the mounting plate 150. The rotating support 121 includes a lower plate 121a, and a left plate 121b and a right plate 121c that are erected from both left and right ends of the lower plate 121a. A rotation shaft 10b that rotates according to the operation of the shift pedal 10 is fixed to the lower plate 121a, and the rotation support 121 rotates in the direction of the arrow shown in FIG. Composed.

  As shown in FIG. 10, the cam member 122 has a substantially “8” shape when viewed from the front, and is composed of an upper cylindrical portion 122 a and a lower cylindrical portion 122 b that are arranged vertically, and a left plate 121 b of the rotating support 121. And the right plate 121c. A first shaft member 131 is inserted into and fixed to the upper cylindrical portion 122a and the upper portion of the rotating support 121, and a second shaft is fixed to the lower cylindrical portion 122b and the upper and lower middle portions of the rotating support 121. The member 132 is inserted and fixed. That is, the cam member 122 is configured to be rotatable integrally with the rotation support body 121 around the second shaft member 132. A recess 122c is formed below the lower cylindrical portion 122b.

  The forward / reverse switching arm 123 is a substantially L-shaped flat plate material in plan view, and is a bent portion that is a portion where one side and the other side forming the L shape intersect with each other, and extends to the right from the lower part of the mounting plate 150. The plate 133 is rotatably supported. One end 123 a of the forward / reverse switching arm 123 is linked and connected to the forward / reverse switching lever 11 via a connecting member 134. At the other end of the forward / reverse switching arm 123, a convex portion 123c that engages with the concave portion 122c of the cam member 122 protrudes upward.

  The forward-side first connecting member 124 is a substantially rhombic flat plate member when viewed from the side, and is disposed on the left side of the rotation support body 121. The forward-side first connection member 124 is rotatably supported by the second shaft member 132 via a bearing 135. A through hole 124a is formed in the upper and lower middle part of the advance-side first connecting member 124 so that the left end 131a of the first shaft member can be inserted.

  The forward-side second connecting member 125 is a flat plate member that is parallel to the body frame 2 and extends in the front-rear direction, and is disposed on the left side of the forward-side first connecting member 124. A third shaft member 136 is inserted into the front end of the advancing side second connecting member 125 and the upper part of the advancing side first connecting member 124, and each is rotatably connected.

  The reverse side first connecting member 126 is a flat plate member having a substantially trapezoidal shape when viewed from the side, and is disposed on the right side of the rotating support 121. The reverse side first connecting member 126 is rotatably supported by the second shaft member 132 via a bearing 137. A through hole 126a is formed in the upper portion of the reverse side first connecting member 126 so that the right end 131b of the first shaft member can be inserted.

  The reverse side second connecting member 127 is a columnar member that is curved in a substantially crank shape in a side view, and is disposed on the left side of the reverse side first connecting member 126. The fourth shaft member 138 is inserted into the rear end of the reverse side second connecting member 127 and the lower part of the reverse side first connecting member 126, and each of them is rotatably connected. The front end of the reverse side second connecting member 127 is disposed to the right of the front end of the forward side second connecting member 125.

  The rotating plate 128 is a flat plate member bent in a substantially “7” shape when viewed from the front, and is disposed on the right side of the front portion of the mounting plate 150. The rotation plate 128 is pivotally supported by the fifth shaft member 139 in the middle of the upper and lower parts, and is configured to be in the neutral position when the operation of the shift pedal 10 is stopped by the neutral biasing spring 140. . A damper 141 is attached to the lower end of the rotating plate 128 so that the rotating plate 128 does not easily rotate.

  The output member 129 is a flat plate member that extends in the front-rear direction in parallel with the body frame 2, and the rear end is disposed at the front end of the reverse side second connecting member 127 and the front end of the forward side second connecting member 125. Then, the upper part of the rotating plate 128 is covered, and these four members are inserted and connected to the sixth shaft member 142. The other end 129a of the output member 129 is connected to the speed transmission arm 13 via a connecting member (not shown).

  In such a forward / reverse switching mechanism 120, when the forward / reverse switching lever 11 is operated, one end 123a of the forward / reverse switching arm 123 is pulled through the connecting means 134, and the forward / reverse switching arm 123 rotates. The cam member 122 slides to the left or right side by the convex portion 123c formed at the other end. At this time, when operated to the “neutral position”, the first shaft member 131 configured integrally with the cam member 122 causes the through hole 124a of the forward-side first connecting member 124 and the reverse-side first connecting member 126 to move. It does not fit with any of the through holes 126a. When the shift pedal 10 is depressed from this state, the rotation shaft 10b rotates in accordance with the depression amount of the shift pedal 10, but the output member 129 maintains its front / rear vertical position. That is, the speed transmission arm 13 does not rotate, and the servo spool 6 does not slide in the front-rear direction.

  Further, when the forward / reverse switching lever 11 is operated to the “advance position”, the first shaft member 131 configured integrally with the cam member 122 is engaged with the through hole 124 a of the advance-side first connecting member 124. Thus, the rotation support body 21 and the forward-side first connection member 124 are connected. When the shift pedal 10 is depressed from this state, the rotation shaft 10b rotates according to the depression amount of the shift pedal 10, and the rotation support 121 rotates in the direction of the arrow shown in FIG. Then, due to the rotation of the rotation support member 121, the output member 129 moves rearward together with the advance side first connecting member 124 and the advance side second connecting member 125. That is, the speed transmission arm 13 rotates rearward, and the servo spool 6 slides rearward due to the rotation of the speed transmission arm 13, and the tractor 1 responds to the operation amount of the transmission pedal 10. And move forward.

  Further, when the forward / reverse switching lever 11 is operated to the “reverse position”, the first shaft member 131 configured integrally with the cam member 122 is engaged with the through hole 126a of the reverse side first connection member 126. Thus, the rotation support body 21 and the reverse side first connection member 126 are connected. When the shift pedal 10 is depressed from this state, the rotation shaft 10b rotates according to the depression amount of the shift pedal 10, and the rotation support 121 rotates in the direction of the arrow shown in FIG. Then, due to the rotation of the rotation support body 121, the output member 129 moves forward together with the reverse-side first connecting member 126 and the reverse-side second connecting member 127. That is, the speed transmission arm 13 rotates forward, and the rotation of the speed transmission arm 13 causes the servo spool 6 to slide forward, so that the tractor 1 corresponds to the operation amount of the transmission pedal 10. And go backwards.

1 Tractor 2 Airframe Frame 6 Servo Spool (Speed changing means)
DESCRIPTION OF SYMBOLS 7 Mission case 8 Driving | operation operation part 10 Shift pedal 10a Turning base 11 Forward / reverse switching lever 20 Forward / reverse switching mechanism 21 Turning support body 22 Forward / reverse switching body 23 Link member 24 Shaft body 25 Forward / backward switching arm 37 Front plate (support) Element)
41 connecting means 50 first universal joint 60 second universal joint 70 holding mechanism 80 belt type continuously variable transmission

Claims (2)

A shift pedal capable of shifting from the neutral position to the highest speed position;
A forward / reverse switching lever that can be switched to a forward position, a reverse position, and a neutral position;
A continuously variable transmission capable of shifting from a forward speed to a reverse speed by operating a speed changing means ;
A forward / reverse switching mechanism linked to the speed change means of the speed change pedal, the forward / reverse switching lever and the continuously variable transmission,
The forward / reverse switching mechanism is
A main body configured in a cylindrical shape and a rotary shaft that protrudes in a radial direction from the outer surface of the main body, and a rotary support body on which the rotary base of the shift pedal is fixed to the rotary shaft;
A forward / reverse switching body having a cylindrical body rotatably supported along the inner surface of the rotational support body and an operation arm projecting outward from the rotational support body from one end of the cylindrical body;
A link member linked to the speed change means of the continuously variable transmission via a first universal joint to the operation arm;
A shaft fixed to the axial center of the cylindrical body;
A forward / reverse switching arm coupled to the shaft body via a second universal joint and coupled to the forward / reverse switching lever via a coupling means;
A holding mechanism for holding the forward / reverse switching arm at a forward position, a reverse position and a neutral position;
A tractor comprising: The holding mechanism is
A pressing member attached to the forward / reverse switching arm;
A support member that supports the support shaft of the forward / reverse switching arm and has a concave portion that is disposed at a predetermined interval on a concentric circle centered on the support shaft at a position facing the pressing member. The tractor according to claim 1, wherein the tractor is configured.

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