The present invention relates to vehicles in which the transmission of drive power from the engine to drive wheels is interrupted by depressing a clutch pedal.
Since depressing a clutch pedal requires relatively strong force, a technique as disclosed in Patent Literature 1 has been proposed for a vehicle with a clutch pedal. In Patent Literature 1, a gas spring is provided between an arm portion with a clutch pedal attached to the lower end thereof and a frame to which the clutch is attached, the frame rotatably supporting the upper end of the arm portion. In this structure, the gas spring acts as repulsive force until the clutch pedal is depressed for a fixed amount. When the depression exceeds the fixed amount, the gas spring acts as assist force. Accordingly, unnecessary depression of the clutch pedal can be prevented by the repulsive force at an early stage of depression, while a clutch switching operation can be facilitated by the assist force at a later stage of depression.
Patent Literature 1: JP 2002-181075 A
In Patent Literature 1, one end of the gas spring is attached to the lower part of the arm portion. Therefore, the clutch pedal and the gas spring are positioned close to each other, causing a problem of damage of the gas spring with the foot of a driver that abuts against the gas spring by mistake when the driver puts the foot on and depresses the clutch pedal.
In this type of vehicle, a reverser lever for switching between forward and backward movements (forward and backward movement switching lever), as disclosed in JP 7-132752 A, is arranged around a circular steering wheel and rotated along the outer periphery of the steering wheel to an arc drawing manner in a forward or backward direction, to thereby operate a reverser clutch in a transmission case. An arcuate movement of such a reverser lever is transmitted via a link mechanism to operate a reverser clutch (forward and backward switching means) in the transmission case.
An example of a method for converting the arcuate rotational movement of the reverser lever into vertical movement is to provide a transmission arm projecting on a plane perpendicular to the center of rotation of a first rotation shaft, which is provided at the base end of the reverser lever, and also provide a lug projecting downward from one end of the transmission arm. A connecting rod whose center line runs in a direction perpendicular to the center line of the first rotation shaft is provided to be engaged with the lug of the transmission arm around the connecting rod. The lug is configured to rotate the connecting rod in response to the rotation of the transmission arm.
In addition, a second rotation shaft is provided in parallel with the center line of rotation of the connecting rod at the lower part thereof. The second rotation shaft is connected with an operation arm and acts as a center of rotation of the operation arm. The operation arm is connected to the upper end of the link mechanism. When the reverser lever is rotated arcuately along the outer periphery of the steering wheel, the movement is transmitted to the link mechanism as the vertical movement. Then, an operation shaft of the reverser clutch is rotated when the arm connected to the link mechanism rotates vertically. Such a structure, however, requires two rotation shafts of the first and second rotation shafts having different centers of rotation in different directions to transmit the movement of the reverser lever to operate the reverser clutch, which lead to a complicated structure.
An object of the present invention, therefore, is to provide a vehicle allowing safe operation of a clutch and capable of switching between forward and backward movements by a simple structure.
According to an embodiment of the present invention as recited in claim 1, a vehicle includes a clutch pedal which, when depressed, interrupts the transmission of drive power from the engine to the drive wheels. The clutch pedal is constituted by a pedal section and an arm portion having the pedal section attached to the lower part thereof. The arm portion can rotate about the upper part thereof and is connected to a clutch disk within a transmission through the link mechanism. An elastic member is provided between the arm portion and a machine body. When the clutch pedal is depressed, the elastic member acts in a pressing-back direction until the clutch pedal reaches a first predetermined position, the pressing-back direction being the direction in which the elastic member presses back the arm portion. When the clutch pedal is depressed beyond the first predetermined position, the elastic member acts in the direction in which the arm portion is pressed. When the clutch pedal is depressed up to a second predetermined position, the clutch disk is separated. In such a vehicle, one end of the elastic member is mounted to an intermediate position of the arm portion, and the other end of the elastic member is mounted to the machine body.
According to the embodiment of the present invention as recited in claim 2, a shielding is provided at the rear end of a bonnet for separating the bonnet from a driver seat in the vehicle as recited in claim 1. The other end of the elastic member is attached to the shielding.
According to the embodiment of the present invention as recited in claim 3, the shielding is provided with an attaching member in the vehicle as recited in claim 2. The attaching member includes a forward and backward movement switching lever that switches between forward and backward operations of the vehicle via link means. The forward and backward movement switching lever includes operation means for driving forward and backward switching means in a mission case. When the forward and backward switching lever is operated, the link means is enabled to rotate in a forward or backward direction of the vehicle about a support point of rotation.
According to the embodiment of the present invention as recited in claim 1, the vehicle includes the clutch pedal which, when depressed, interrupts the transmission of drive power from the engine to the drive wheels. The clutch pedal is constituted by the pedal section and the arm portion having the pedal section attached to the lower part thereof. The arm portion can rotate about the upper part thereof and is connected to the clutch disk within the transmission through the link mechanism. The elastic member is provided between the arm portion and the machine body. When the clutch pedal is depressed, the elastic member acts in a pressing-back direction until the clutch pedal reaches the first predetermined position, the pressing-back direction being the direction in which the elastic member presses back the arm portion. When the clutch pedal is depressed beyond the first predetermined position, the elastic member acts in the direction in which the arm portion is pressed in. When the clutch pedal is depressed up to a second predetermined position, the clutch disk is separated. In such a vehicle, one end of the elastic member is mounted to the intermediate position of the arm portion, and the other end of the elastic member is mounted to the machine body.
Accordingly, the risk of damaging the elastic member with the foot of a driver that abuts against the elastic member by mistake when the driver puts the foot on and depress the clutch pedal can be eliminated. The clutch disk can be separated easily because the elastic member assists depression when the clutch pedal is depressed beyond the first predetermined position. It is possible, therefore, to provide a vehicle with a clutch pedal having excellent operability and allowing safe operation of the clutch. Further, the erroneous operation of the clutch pedal can be prevented, as the counterforce acts in the pressing-back direction at least up to the first predetermined position when the driver depresses the clutch pedal by mistake.
According to the embodiment of the present invention as recited in claim 2, the shielding is provided at the rear end of the bonnet for separating the bonnet from a driver seat, with the other end of the elastic member attached to the shielding. The shielding decreases transmission of heat discharged from the engine, and such a shielding can also be used to mount the elastic member to provide a vehicle with a reduced number of parts.
According to the embodiment of the present invention as recited in claim 3, the attaching member is provided at the shielding, the attaching member including the forward and backward movement switching lever for switching between forward and backward operations of the vehicle via the link means. The forward and backward movement switching lever includes the operation means for driving forward and backward switching means in the mission case. When the forward and backward switching means is operated, the link means is enabled to rotate in a forward or backward direction of the vehicle about a support point of rotation.
Accordingly, the forward and backward switching lever can tilt in a generally linear direction in a forward or backward direction of the vehicle about the support point of rotation of the link means. It is possible, therefore, to provide a farm working vehicle capable of switching between the forward and backward movements by a simple structure. Since the forward and backward switching lever can include only one support point of rotation, the operation of the forward and backward switching lever can be simplified to improve operability.
An embodiment of the present invention will be described in detail below by referring to the accompanying drawings. In the description below, “front” refers to a direction of forward movement of a tractor (vehicle with a clutch pedal) 10, “rear” refers to a direction of backward movement of the tractor 10, and “right and left” refers to the right and left directions relative to the direction of the tractor 10 moving forward.
In the rear part of the bonnet 11, a dashboard 18 is provided via an air cut plate (shielding) which will be described in detail later. The dashboard 18 includes a panel that displays speed, a remaining fuel amount, etc. A steering column cover 20 is provided adjacent to and behind the dashboard 18. A steering wheel 21 is provided in a projecting manner at the upper end of the steering column cover 20. On the surface of the steering column cover 20, a reverser lever 22 is provided on the left side of the steering wheel 21, and an acceleration lever is provided on the right side of the steering wheel (operation unit) 21. Right and left brake pedals are provided in the lower right side of the steering column cover 20, and a clutch pedal 25 is provided in the lower left side of the steering column cover 20.
A driver seat (operation unit) 27 is provided behind the steering column cover 20 at a fixed distance therefrom. The driver seat 27 is arranged between the right and left fenders 17, 17. The driver seat 27 is mounted on a driving cab 28. A hydraulic lift lever 31 and a PTO lever 32 are provided on the right side of the top face of the driving cab 28. A sub shift lever 33 is provided on the left side of the top face of the driving cab 28. A main shift lever is provided on the right side of the front face of the driving cab 28, and a 4WD lever is provided on the left side of the front face of the driving cab 28.
A floor 34 is provided between the driving cab 28 and the bonnet 11. The floor 34 is provided for a driver to put the foot on when the driver steps on an off the tractor 10 or during driving the tractor 10. A transmission case TM that stores transmission is arranged below the floor 34. The transmission case TM is fixed in the rear part of the chassis 14. Power from the engine E is transmitted to the rear wheels 16 via the transmission.
A fuel tank 36 is arranged adjacent to and behind the driver seat 27. The fuel tank 36 is arranged between the right and left fenders 17, 17. A roll-over protective structures (ROPS) 37 is provided in a projecting manner at the rear end of the right and left fenders 17, 17. The ROPS 37 is fixed with an axle case AC of the rear wheels 16. The axle case AC is fixed with the transmission case TM.
The first rotation shaft 50 includes an internal rod 50e, and a left end portion 50a, a center portion 50b, a right side portion 50c, and a right end portion 50d of a cylinder externally provided over the rod 50e. The right side portion 50c of the cylinder is fixedly attached to the rod 50e. The left end portion 50a and the right end portion 50d of the cylinder are rotatably supported by the rod 50e. The center portion 50b of the cylinder is fixedly attached to brackets 48a, 48b, which will be described later, to rotatably support the rod 50e. Accordingly, when the right side portion 50c of the cylinder rotates, the rod 50e alone rotates synchronously. A base end side of an arm portion 24Ab of the brake pedal 24A is fixedly attached to the right side portion 50c of the cylinder of the first rotation shaft 50. A base end side of an arm portion 24Bb of the brake pedal 24B is fixedly attached to the right end portion 50d of the first rotation shaft 50.
One end of a first link plate 51 is fixedly attached to the left end of the rod 50e. Thus, the first link plate 51 rotates synchronously with the right side portion 50c of the cylinder. Meanwhile, another link plate (which is not shown) is fixedly attached to the right end of the right end portion 50d of the cylinder by welding or the like. The link plate rotates synchronously with the right end portion 50d of the cylinder.
One end of a first link rod 52 is rotatably attached to the first link plate 51 via a pin 53. The first link rod 52 is formed by a metal rod having planar portions at both ends thereof at which the first link plate 51 is connected. The other end of the first link rod 52 is rotatably attached to one end of a second link plate 55 via a pin 54. The second link plate 55 is fixedly provided on the outer periphery of a second rotating portion 58.
The second rotating portion 58 is formed like a roller and includes an internal rod as a shaft. A cylindrical portion is fixedly provided on the outer periphery near the center of the shaft. The cylindrical portion is fixedly attached to the floor 34. One end of a second link rod 57 is rotatably attached to the other end of the second link plate 55 via a pin 56.
The other end of the second link rod 57 is rotatably connected to the tip end of an operation arm 59 via a pin 59b. The rear end of the operation arm 59 is rotatably attached to a braking mechanism B of the rear wheels 16 via a rotation shaft 59a. The operation arm 59 and the rotation shaft 59a are fixedly provided such that the rotation shaft 59a rotates along with the rotation of the operation arm 59. When the rotation shaft 59a rotates, the brake of the left rear wheels 16 works.
A link plate identical to the first link plate 51 that acts with the left brake pedal 24A is fixedly attached, by welding or the like, to the right end of the right end portion 50d of the cylinder connected to the right brake pedal 24B. Similarly to the above, the first link plate 51 that acts with the right brake pedal 24B has connected thereto the first link rod 52, the second link plate 55, the second rotating portion 58, the second link rod 57, and the operation arm 59. The operation arm 59 is rotatably attached to the braking mechanism B of the right rear wheel 16 via the rotation shaft 59a.
The clutch pedal 25 is constituted by a pedal section 25a and an arm portion 25b. The pedal section 25a is fixed on the upper side of the lower end portion of the arm portion 25b by a bolt or the like. The surface of the pedal section 25a is provided with slip prevention treatment (such as making unevenness or plastering rubber on the surface). The upper end of the arm portion 25b is fixedly attached to the left end portion 50a of the cylinder, and a first clutch link plate 70 is fixedly attached to the left end portion 50a of the cylinder. The clutch pedal 25 is connected with a clutch disk in the transmission TM via the link mechanism. The link mechanism includes a second clutch link plate 71, a clutch link rod 72, a clutch operation arm 73, a rotation shaft 74, etc.
The clutch link plate 70 is a rectangular metal plate, with one end thereof fixedly attached to the left end portion 50a of the cylinder of the first rotation shaft 50. The other end of the clutch link plate 70 is rotatably connected to the tip end of the second clutch link plate 71 via a pin 71a. The other end of the second clutch link plate 71 is fixedly attached to the tip end of the clutch link rod 72 by a bolt. The rear end of the clutch link rod 72 is rotatably connected to the tip end of the clutch operation arm 73 via a pin. The other end of the clutch operation arm 73 is fixedly attached to the rotation shaft 74. The rotation shaft 74 penetrates through the mission case TM and rotates along with the rotation of the clutch operation arm 73. The rotation of the rotation shaft 74 causes the main clutch, which is connected to the output shaft of the engine to be disconnected.
The brackets 48a, 48b are fixedly attached to the center portion 50b of the cylinder of the first rotation shaft 50. The first rotation shaft 50 is fixedly attached to the air cut plate (shielding plate) 49 via the brackets 48a, 48b. Since the first rotation shaft 50 is provided across the air cut plate 49 in a width direction thereof, the rigidity of the air cut plate 49 is strengthened by the first rotation shaft 50.
A stopper arm 60 is further provided fixedly at the left end portion 50a of the cylinder of the first rotation shaft 50. The stopper arm 60 is configured to restrict a rotation range of the clutch pedal 25. The tip end of the stopper arm 60 is arranged in a clutch stopper 61. The tip end of the stopper arm 60 is allowed to move vertically within a predetermined range in the clutch stopper 61 along with the movement of the clutch pedal 25. The clutch stopper 61 is fixed to the air cut plate 49 by welding.
Meanwhile, the upper end of a gas spring (elastic member) GS is attached at a position of the arm portion 25b slightly upper side from the center (intermediate position of the arm portion) of the clutch pedal 25. The lower end of the gas spring GS is attached to the bracket 49X fixedly attached to the air cut plate 49. The air cut plate 49 is fixed to the upper end of the transmission case (machine body) TM via the brackets 48a, 48b.
Specifically, as illustrated in
A bracket 49X is fixedly attached to the left lower portion of the air cut plate 49. The bracket 49X is formed by a metal plate that is folded in an L shape when seen from the side. A through hole 49XH is formed in the center portion of a vertical surface of the bracket 49X. The through hole 49XH is combined with a through hole formed at the lower end of the gas spring GS, and fixed to each other by a rivet pin or the like. The gas spring GS is rotatably attached to the bracket 49X.
Next, the procedures of operating the clutch pedal 25 will be described by referring to
First, when a driver puts the left foot on the pedal section 25a and starts depressing it, the arm portion 25b rotates clockwise about the left end portion 50a of the cylinder as a support point of rotation in
Following the idling period (position P1 in
Beyond the position P2 (period Z2 in
In
In the timing chart of
The position of the stay 25X of the clutch pedal 25 is not limited to the above case, and may be arranged at any intermediate position of the arm portion 25b.
The gas spring GS described above may be replaced by a coil spring (elastic member) attached between the stay 25X and the bracket 49X.
Also, in the above case, the lower end of the gas spring GS is attached to the bracket 49X of the air cut plate (shielding) 49, but it is not limited thereto, and may be attached to any member (such as the chassis 14, the transmission case TM, or the braking mechanism B) serving as a constituent member of the machine body of the tractor 10. The lower end of the gas spring GS may not be attached directly to the constituent member of the machine body, and may be attached via the stay or bracket.
Next, the link means of the reverser lever will be described.
As illustrated in
Next, the main portion of the present example will be described by referring to
The connecting member 96 is formed by bending a metal plate in a U shape and, to the inside the curved portion, the lower portion of the shaft portion 22b is fixedly attached. Through holes are formed on both ends of the connecting member 96 to be connected rotatably with the rotation member 95 by a bolt BT1. The rotation member 95 is made from a metal column with one end being notched on both sides to form a planar portion. A through hole is formed in the planar portion. The connecting member 96 is arranged such that the internal surface thereof abuts against the planar portion. The through hole of the connecting member 96 is aligned with the through hole of the planar portion of the rotation member 95, through which the bolt BT1 is inserted to rotatably connect the connecting member 96 with the rotation member 95. By providing the planar portion on the rotation member 95 and having the internal surface of the plate-like connecting member 96 abut against the planar portion, the connecting member 96 and the rotation member 95 can be securely combined and rotated when the reverser lever 22 is rotated, which will be described later.
The other end of the rotation member 95 is rotatably supported by a supporting member 94. The supporting member 94 is made from a metal plate by bending it into a gate-like shape. The supporting member 94 is machined to follow the shape of the side face of a cylindrical steering post 21P and then fixed to the side face of the steering post 21P by welding. The other end of the rotation member 95 is attached to the supporting member 94 via a sleeve member 95O. The sleeve member 95O is made from a metal cylinder which is fitted in the through hole formed in the supporting member 94 and fixed to the supporting member 94 by welding. The rotation member 95 can rotate relative to the sleeve member 95O. Meanwhile, a retainer ring 95R is attached at the end of the rotation member 95 to prevent it from being slipped from the sleeve member 95O.
A link member (link means) 97 is fitted at the center portion of the rotation member 95, i.e., between the supporting member 94 and the connecting member 96. Accordingly, the center line of the rotation member 95 becomes the support point of rotation of the link member 97. The link member 97 is formed by machining a metal plate to have a narrow tip end 97T. A through hole is formed in the tip end 97T to rotatably connect with the reverser lever link 83 by a pin PN1. The reverser lever link 83 is formed by an upper attaching portion 83U and a rod portion 83R. The attaching portion 83U is formed by bending a metal plate into a U shape and with the open part thereof fixed facing upward to the rod portion 83R by welding. A through hole is formed at the upper end of the attaching portion 83U. The tip end 97T of the link member 97 is pinched by the attaching portion 83U and both members are rotatably attached by the pin PN1. A retainer pin is attached on the tip end of the pin PN1.
A recess 22bu is formed at the lower end portion of the shaft portion 22b. Meanwhile, a through hole 970 is formed in the lower portion of the rear end portion 97E of the link member 97. A coil spring SP is hooked between the recess 22bu and the through hole 970. Since the connecting member 96 can rotate relative to the rotation member 95, the lower portion of the shaft portion 22b is energized toward the link member 97 side with the bolt BT1 serving as the support point. The lower end of the shaft portion 22b is inserted into the guide hole 93D, such that the lower portion of the shaft portion 22b can move within the range of the guide hole 93D.
A pair of attaching members 91, 91 is extendingly provided to the brackets 48a, 48b fixedly attached to the air cut plate 49. A column member 92 is attached by welding at the tip end of each attaching member 91. The column member 92 is formed as a column-shaped metal member having a through hole in the center.
As illustrated in
The post supporting member 93 is attached to the pair of attaching members 91, 91 at a predetermined angle (see
The rod portion 83R of the reverser lever link 83 is formed by bending a column at three locations. The lower end portion of the rod portion 83R is machined into a plate-like portion in which a through hole is formed. This through hole is aligned with the through hole formed in one end of the operation arm 84 and rotatably connected together by a pin PN2. Another through hole is formed in the other end of the operation arm 84 to which one end of the rotation shaft 85 is fixed. The other end of the rotation shaft 85 is arranged in the transmission case TM.
In the tractor 10 formed as above, a method of operating the reverser lever 22 will be described by referring to the drawings up to
If it is desired to advance the tractor 10, a driver first grasps the grip portion 22a with the left hand and pulls down the reverser lever 22 in a direction closer to the steering wheel 21 (the shaft portion 22b indicated by a two-dot chain line in
The reverser lever 22 is then pulled down in a forward direction (direction F in
In this state, if it is desired to stop the tractor 10 and turn off the engine, the reverser lever 22 is returned in a reverse direction (direction B in
If it is desired to reverse the tractor 10 from this state, the driver grasps the grip portion 22a of the reverser lever 22 with the left hand, and pulls down the reverser lever 22 in a direction closer to the steering wheel 21 (the shaft portion 22b indicated by the two-dot chain line in
The reverser lever 22 is then pulled down in a backward direction (direction B in
The shaft portion 22b of the reverser lever 22 may be formed as illustrated in
Specifically, the reverser lever is constituted by a grip portion (which is not shown and identical to the grip portion 22a) and a shaft portion 122b. The shaft portion 122b is made from a metal round rod having the upper and lower parts thereof opposite to each other bent at a generally right angle.
An end of the shaft portion 122b is rotatably supported by a supporting member 194. The supporting member 194 is made from a metal plate by bending it into a gate-like shape. The supporting member 194 is machined to follow the shape of the side face of the cylindrical steering post 21P and then fixed to the side face of the steering post 21P by welding. The end of the shaft portion 122b is attached to the supporting member 194 via a sleeve member 195O. The sleeve member 195O is made from a metal cylinder which is fitted in the through hole formed in the supporting member 194 and fixed to the supporting member 194 by welding. The end of the shaft portion 122b can rotate relative to the sleeve member 195O. Meanwhile, a retainer ring 195R is attached at the end of the shaft portion 122b to prevent it from being slipped from the sleeve member 195O.
The shaft portion 122b penetrates through and fixedly attached to the link member 97 by welding or the like, and can be combined and rotated with the shaft portion 122b. The support point of the link member 97 is the center line of the shaft portion 122b.
Two stoppers 194P project on the surface of the supporting member 194. The stoppers 194P are configured to restrict the movement of the link member 97 when the shaft portion 122b rotates. When the link member 97 rotates forward, i.e., when the reverser lever is pulled down in a forward direction, it abuts against the front stopper 194P. Meanwhile, when the link member 97 rotates backward, i.e., when the reverser is pulled down in a backward direction, it abuts the rear stopper 194P (see
The present invention is not limited to the above embodiments. Instead, it can be implemented in any form without departing from the scope of the present invention.
Application of the vehicles according to the embodiments of the present invention is not limited to tractors. Instead, the present invention is applicable to other farm work vehicles (such as a combine, a rice transplanter, or a lawn more), vehicles having a clutch, such as a car, a truck, and a construction work vehicle (such as a backhoe or a bulldozer), a folk lift, and so on.
Number | Date | Country | Kind |
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2012-134263 | Jun 2012 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2012/082252 | 12/12/2012 | WO | 00 |