JP2006240324A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a linkage constitution from a backward change pedal to a trunnion before an HST. <P>SOLUTION: This working vehicle is equipped with a static hydraulic continuously variable transmission receiving hydraulic oil from a hydraulic pump 23, driving a hydraulic motor 28, and driving a drive wheel by a driving force. A shifting pedal is constituted by a forward change pedal 3F and a backward change pedal 3R rotating around a lateral shaft 27. The vehicle is provided with a relay shaft 31 linking in a normal direction based on a forward treading operation of the forward change pedal 3F, and linking in a reverse direction based on a forward treading operation of the backward change pedal 3F. The normal and reverse rotations of the relay shaft 31 are adapted to link with a trunnion shaft 29 of the hydraulic pump 23. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a work vehicle including a hydrostatic continuously variable transmission.

Conventionally, in a work vehicle equipped with a hydrostatic continuously variable transmission, the bases (13a) and (14a) of the forward travel pedal (13) and the reverse travel pedal (14) are turned as in Japanese Patent Publication No. 08-5346. The forward travel pedal (13) is pivotally mounted, and one end of a rod (19) is locked to the upper portion of the base (13a), and the reverse travel pedal (14) is connected to the base (14a). One end of the rod (20) is locked to the lower part. The other ends of the rods (19) and (20) are connected to the arm (18) of the trunnion shaft (17) of the HST (16). In other words, a forward pedal and a reverse pedal are provided, and when the forward pedal is stepped on, the pedal shaft is rotated and the trunnion shaft is rotated via the link mechanism, so that the hydraulic motor is driven forward by interlocking with the swash plate of the hydraulic pump. Yes, when the reverse pedal is stepped on, the second pedal shaft coaxial with the pedal shaft is rotated, the trunnion shaft is reversely rotated through the link mechanism, and the hydraulic motor is driven to the reverse side. The pedal side and the reverse pedal side have independent interlocking configurations.
Japanese Patent Publication No. 08-5346

  However, in the above-described embodiment, the forward pedal side link mechanism and the reverse side link mechanism are provided, and when the distance between the speed change pedal and the trunnion shaft is long, the link mechanism is bulky and the trunnion shaft is improved in operability. There is a risk that it cannot be maintained.

In the present invention, in order to solve the above-described problems, a work vehicle is configured as follows.
In other words, according to the first aspect of the present invention, the operation is provided with the hydrostatic continuously variable transmission that receives the pressure oil from the hydraulic pump (23), drives the hydraulic motor (28), and drives the driving wheels by this driving force. In the vehicle, the shift operation pedal is composed of a forward shift pedal (3F) and a reverse shift pedal (3R) that rotate about the horizontal axis (27), and is based on an operation of depressing the forward shift pedal (3F) forward. A relay shaft (31) interlocking with the forward rotation direction and interlocking with the reverse rotation direction based on the forward depression operation of the reverse shift pedal (3R) is provided, and the forward / reverse rotation of the relay shaft (31) is controlled by a hydraulic pump (23 ) Of the trunnion shaft (29).

  With the above-described configuration, the relay shaft (31) is linked to forward / reverse rotation by stepping forward of the forward / reverse shift pedal (3F) (3R) to move the relay shaft (31) forward and backward. 3F, 3R), and the horizontal shaft (27) that supports the forward / reverse shift pedal (3F, 3R) so that it can be depressed is a single shaft, that is, the front / rear shift pedal (3F, 3R). ) Can be the same axis, simplifying the configuration.

  According to the second aspect of the present invention, the relay shaft (31) is connected to the relay shaft (31) that is linked to forward / reverse rotation by depressing the forward shift pedal (3F) and depressing the reverse shift pedal (3R). The detection device (34) for detecting reverse rotation is provided, and based on the detection result of the detection device (34), the forward / reverse rotation motor (35) is interlocked in a predetermined manner and the trunnion shaft (29) is interlocked. The work vehicle described was used.

  According to this, since the rotation of the relay shaft (31) is interlocked with both the forward shift pedal (3F) and the reverse shift pedal (3R), a detection device (for detecting the movement of the relay shaft (31) ( It is sufficient to provide a single 34).

  Furthermore, in the invention according to claim 3, the neutral position holding means is configured on the relay shaft (31) interlocked with the forward / reverse rotation by depressing operation of the forward shift pedal (3F) and depressing operation of the reverse shift pedal (3R). A work vehicle according to claim 1 or 2, wherein

  Since the rotation of the relay shaft (31) is linked to both the forward shift pedal (3F) and the reverse shift pedal (3R), the neutrality of the relay shaft (31) is maintained to maintain the conventional trunnion shaft. It can be replaced with a neutral holding configuration, and adjustment work including the shift pedal is easy.

  According to the first aspect of the present invention, the relay shaft (31) can be disposed in the vicinity of the forward / reverse transmission pedal (3F, 3R), and the forward / reverse transmission pedal (3F, 3R) can be depressed. The horizontal shaft (27) that is supported by the single shaft, that is, the shaft that supports the front and rear transmission pedals (3F, 3R) can be the same shaft, and the configuration is simplified. In addition, the link between the trunnion shaft and the relay shaft is effective with a single link mechanism.

  In the invention according to claim 2, since the rotation of the relay shaft (31) is linked to both the forward shift pedal (3F) and the reverse shift pedal (3R), the movement of the relay shaft (31). It is sufficient to provide a single detection device (34) for detecting (for example, a potentiometer), and the cost can be reduced.

  Further, according to the third aspect of the present invention, it is possible to replace the conventional trunnion shaft with neutrality by holding the neutral of the relay shaft (31), and the adjustment work including the shift pedal is easy.

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, an engine E, a clutch housing 6 and a transmission case 8 arranged at the rear of the vehicle body of a traveling vehicle are integrated with each other via a vehicle body frame 1, and a front axle housing 9 at the front can be steered by a steering handle 10. A front wheel 11 and a rear wheel 12, and a rear wheel 12 is mounted on the front end of the rear axle housing 13 on both the left and right sides of the engine E, and the front and rear wheels 11, 12 are driven to travel. Yes. A pilot seat is provided on the body frame 1 above the mission case 8.

The mower M provided in front of the mission case 8 includes a link mechanism 15 that rotates up and down by a lift arm, a mower lifting hydraulic cylinder S1, and the like.
A hydraulic continuously variable transmission (HST) 4 serving as a main transmission is provided in a mission case 8. As shown in FIG. 2, the power of the engine E is transmitted from the engine output shaft 5 through the main clutch 54 in the clutch housing 6 to the HST input shaft 19 and is neutralized by the HST speed change lever 36 or the forward / reverse pedals 3F and 3R. Switching between forward F and reverse R from position N and interlocking with these continuously variable transmissions is transmitted to the auxiliary transmission 21 and further to the differential gear mechanism of the rear wheels 12 and the output shaft to the front wheels 11 and the like. Be transmitted.

In the hydraulic continuously variable transmission (HST) 4, the inclination angle of the swash plate 22 of the variable displacement pump 23 shown in FIG. 2 is changed, and the rotation of the output shaft 53 by the HST hydraulic motor 28 is continuously variable.
The power transmission mechanism of the traveling vehicle of the embodiment shown in FIG. 2 includes an HST 4 including a high, middle, and low three-stage auxiliary transmission 21, a variable displacement pump 23, and an HST hydraulic motor 28. Further, before driving the HST input shaft 19 from the main clutch 54, the power extracted by branching the PTO input shaft 56 is extracted to the PTO shaft 55 via the PTO transmission 57.

  In the hydraulic continuously variable transmission (HST) 4, the variable displacement pump 23 and the HST hydraulic motor 28 are connected by a closed hydraulic circuit 50, and the inclination angle of the swash plate 22 of the variable displacement pump 23 is shifted forward and backward. The forward / reverse rotation position of the trunnion shaft 29 is adjusted according to the depression operation of the pedals 3F and 3R, the inclination angle is changed in conjunction with the swash plate 22, the input rotation of the HST input shaft 19 is continuously variable, In addition, it is configured to output from the HST input shaft 53 by switching between normal and reverse.

  The power from the HST output shaft 53 is extracted to the traveling shaft 58, and the power is extracted from the traveling shaft 58 to the differential device 59 for transmission to the rear wheel 12, the front wheel transmission shaft 60, and the differential device 61 for transmission to the front wheel 11. It is. Note that a four-wheel drive four-wheel clutch gear 62 for turning on and off the transmission of the front wheel transmission shaft 60 is provided between the PTO input shaft 56 and the front wheel drive shaft 60.

  FIG. 3 shows a hydraulic circuit diagram of the traveling vehicle of this embodiment. This hydraulic circuit includes a front-wheel-side hydraulic steering unit 30a that steers the front wheels 11 by operating the front-wheel steering hydraulic cylinder 42a by pressure oil from a pump P1, which is one of the hydraulic pumps 2, and a rear-wheel power steering cylinder. The hydraulic circuit for the rear wheel side hydraulic steering unit 30b that steers the rear wheel 12 by operating the motor 42b is branched in parallel by the diversion valve, and the pressure oil that passes through these units 30a and 30b is supplied to the HST hydraulic circuit 44. It is configured to be sent as charge oil. Further, a hydraulic circuit 46 for operating the PTO clutch switch 45 of the mower M is arranged in series on the upper side of the hydraulic steering units 30a, 30b and the HST hydraulic circuit 44.

Further, the mower M moves up and down by the expansion and contraction of the mower lifting hydraulic cylinder S1 by the pressure oil from the pump P2 which is one of the hydraulic pumps 2.
Next, based on FIGS. 4 to 6, a description will be given of a cooperative configuration between the forward / reverse shift pedals 3 </ b> F and 3 </ b> R and the trunnion shaft 29. The pedal arm 25F of the forward shift pedal 3F and the pedal arm 25R of the reverse shift pedal 3R are fixed to the cylindrical shaft 26 so as to be arranged side by side. In this example, the cylindrical shaft 26 is detachably fitted to a horizontal axis), and is configured to be rotatable around the horizontal axis 27 cores.

  A relay shaft 31 positioned in front of the horizontal shaft 27 and parallel to the horizontal shaft 27 is rotatably supported by a stay 32 extending from the frame 1 side and an appropriate support forming member of the vehicle body frame 1. The relay shaft 31 is provided with stays 32F and 32R fixed to the front and rear in a side view. Of the pedal arms 25F, 25R, the pedal arm 25F provided on the left side and the forward plate 31F are connected by a link 33F, while the pedal arm 25R provided on the right side and the rear plate 31R are connected by a link 33R. Yes.

  Accordingly, when the forward shift pedal 3F is depressed forward, the relay shaft 31 is rotated in the direction of the arrow (A) via the link 33F and the plate 31F, and when the reverse shift pedal 3R is depressed forward in the same direction, the link 33R and the plate The relay shaft 31 is rotated in the reverse arrow (A) direction via 31R.

  The rotation of the relay shaft 31 around the axis is replaced with an electrical displacement amount of a forward / reverse position sensor 34 as a detection device provided near the outside of the relay shaft 31, and by detecting the displacement amount of the position sensor 34. The forward / reverse rotation motor 35 provided at the end of the trunnion shaft 29 is controlled to rotate in a predetermined manner. The actuator 34a of the position sensor 34 is configured to be able to detect an electrical resistance value by engaging an operating pin 31a provided at the shaft end of the relay shaft 31 and rotating the actuator 34a about the support portion. .

  A neutral return mechanism is configured between the front and rear shift pedals 3F and 3R provided side by side. That is, the other end of the neutral return link 37 formed in an L shape and having one end rotatably fitted to the cylindrical shaft 26 is connected to the body frame 1 side by the spring 38. A roller 40 provided on the relay shaft 31 via a holding plate 39 is brought into sliding contact with the inner peripheral edge 37a of the neutral return link 37. The roller 40 is fitted with the neutral return link 37 by a biasing action of a spring 38. The output value of the position sensor 34 at the position reaching the joint recess is set to the neutral position.

  As described above, the forward shift pedal 3F and the reverse shift pedal 3R are provided so as to be rotatable around the axis of the horizontal axis 27, the relay shaft 31 is provided in the vicinity of the horizontal axis 27, and each of the forward and reverse shift pedals, the relay shaft, During this period, the relay shaft 31 is interlocked with the forward rotation direction by depressing the forward shift pedal 3F, and the relay shaft 31 is reversely rotated by the depressing operation of the reverse shift pedal 3R in the same direction as the forward shift pedal 3F. By providing an interlocking mechanism that interlocks with the front and rear shift pedals 3F and 3R, the horizontal shaft 27 that supports the forward and reverse shift pedals 3F and 3R is operated as a single axis, that is, the axis that supports the front and rear shift pedals 3F and 3R is the same axis. Can simplify the configuration.

  Further, since the relay shaft 31 is configured to forward and reverse, the relay shaft 31 can be neutrally held by the neutral return mechanism, and the position sensor 34 can be interlocked with the shaft end of the relay shaft 31. -These components can be compactly assembled in the vicinity of the reverse shift pedals 3F, 3R.

  4 to 6, the potentiometer 34 is provided at one end of the relay shaft 31. However, as shown in FIGS. 7 and 8, the relay shaft 31 is provided with a bracket 47, and the trunnion shaft 29 provided at the rear portion is connected to the trunnion shaft 29. The connection link 48 is provided between the two. In this configuration, the relay shaft 31 is rotated forward and backward based on the depressing operation of the forward / reverse speed change pedals 3F, 3R, whereby the trunnion shaft 29 is rotationally interlocked to the forward side or the reverse side via the connecting link 48. It is. In this case, the neutral holding mechanism is set on the trunnion shaft 29 side. That is, a trunnion arm 41 provided integrally with the trunnion shaft 29 is provided, the connecting link 48 is connected to the trunnion arm 41, and a roller 43 is provided at the upper end of the trunnion arm 41. The neutral holding plate 52 pivotally supported by the roller 43 is biased toward the roller 43 and positioned. As shown in FIG. 9, the neutral holding plate 52 has an inclination angle on the side 52b close to the rotation fulcrum 52a and a shape in the vicinity of the rotation of the trunnion shaft 29 that is larger than the curvature radius R2 on the opposite side. The curvature radius R1 is set to a large shape 52c (FIG. 9 (a)), or the shape 52c is formed into a straight line 52d (FIG. 9 (b)), and the tension of the spring for urging the neutral holding plate 52 is excessive. The trunnion shaft 29 can be reliably held in a neutral posture without increasing the size.

  If comprised as mentioned above, the horizontal axis | shaft 27 as a support shaft which supports the forward transmission pedal 3F and the reverse transmission pedal 3R similarly to the above can be made common, and a structure can be simplified. The neutral return mechanism in the configuration in the figure is configured on the side of the conventionally known trunnion shaft 29. Reference numeral 49 denotes an auto-cruise mechanism for maintaining the operation interlocking position of the trunnion shaft 29 at a predetermined position so as to maintain a constant vehicle speed without performing a shift pedal operation. The auto-cruise lever 51 is connected to the relay shaft 31. Between the trunnion shaft 29 and the trunnion shaft 29, and a connecting link 63 is formed between the trunnion shaft 29. A frictional positioning means having a multi-layer shoe member is formed on the base side of the auto cruise lever 51. The auto cruise lever 51 is provided in two positions so as to be reciprocally operated. When the auto cruise lever 51 is tilted, the frictional positioning means is operated to hold the operation position of the trunnion shaft 29, so that the vehicle body can travel at a constant speed. The auto cruise lever 51 is configured to be interlocked with a brake pedal (not shown) by a second connecting link 64 and to release the above-described constant speed traveling by a stepping operation.

  10 and 11 relate to the improvement of the auto cruise lever. A support shaft 65 for pivotally supporting the base portion 51a of the auto cruise lever 51 is supported by a fixed plate 66 that is erected from the vehicle body. The shoe member 67 and the washer 68 are superposed on the base portion 51a. A spring 71 is interposed between the washer 68 and the fixed nut 69 or the receiving portion 70 positioned on the fixed nut 69 from the back and mounted on the support shaft 65. Further, a wire 73 is connected to a cup-shaped connecting member 72 provided integrally with the washer 68, and the other end of the wire 73 is connected to a brake arm 76 that is linked to a rotating shaft 75 of the brake pedal 74. Reference numeral 77 denotes a wire that replaces the connecting link 64, and is linked to release the auto cruise lever 51 from the constant speed running state by operating the forward / reverse pedal.

  As described above, when the constant speed traveling means including the shoe member 67, the spring 71 and the like is configured at the base of the auto cruise lever 51, and the spring 71 is configured to be interlocked with the constant speed traveling releasing means such as a brake pedal, When the brake pedal 74 is depressed by operating the auto cruise lever 51 in the constant speed traveling state, the spring 71 is shortened via the wire 73, the connecting member 72, and the washer 68, and the shoe member by the spring 71 is shortened. The pressure contact state 67 is released, and the release from the constant speed traveling is performed. As described above, since the action of the pressure contact spring 71 of the shoe member 67 is directly released, the release from the constant speed traveling is easily and reliably performed.

  FIG. 12 relates to constant speed traveling control including an auto cruise switch 80. 4, 5, and 8, in the transmission including the position sensor 34 for detecting the rotational position of the relay shaft 31 and the forward / reverse motor 35 on the trunnion shaft 29 side, the auto cruise switch 80 is turned on. Basically, the forward / reverse motor 35 is controlled so as to maintain the vehicle speed at the time of the on operation, and the auto-cruise mechanism is configured. In such an auto-cruise mechanism, a vehicle speed sensor 81 is provided, and when the vehicle speed is “0” based on the vehicle speed detection result by the vehicle speed sensor 81, the previous memory position stored in advance in the storage device is set. In this state, the trunnion shaft 29 is fixed. When the vehicle speed is not “0”, the trunnion shaft 29 is fixed at the current vehicle speed. With this configuration, even if the vehicle speed is “0”, the operator automatically increases the vehicle speed to the previous set position, and the previous constant speed state does not reach the critical speed. Because it is normal, it can easily reach a predetermined speed safely.

It is a side view of a traveling vehicle. FIG. 2 is a transmission configuration diagram of the traveling vehicle of FIG. FIG. 2 is a hydraulic circuit diagram of the traveling vehicle of FIG. 1. It is a side view of a forward / reverse shift pedal pedal support. FIG. 5 is a plan view of FIG. 4. It is an outline side view. It is a side view of a forward / reverse shift pedal pedal support showing a different example. FIG. 8 is a plan view of the forward / reverse shift pedal support portion of FIG. 7. It is a front view of a neutral holding plate (a) (b). It is a side view of the principal part provided with the auto-cruise mechanism. It is a partially expanded side view of FIG. It is a flowchart figure.

Explanation of symbols

3F forward shift pedal 3R reverse shift pedal 4 hydrostatic continuously variable transmission 11 front wheel 12 rear wheel 22 swash plate 23 variable displacement pump 25 pedal arm 26 cylinder shaft 27 horizontal shaft 28 HST hydraulic motor 29 trunnion shaft 31 relay shaft 32F, 32R stay 33F, 33R link 34 position sensor (detection device)
35 Forward / reverse motor 37 Neutral holding link

Claims (3)

  In a work vehicle having a hydrostatic continuously variable transmission that receives pressure oil from a hydraulic pump (23) to drive a hydraulic motor (28) and drive driving wheels by this driving force, 27) The forward shift pedal (3F) and the reverse shift pedal (3R) that rotate about the reverse shift pedal (3R) are interlocked in the forward rotation direction based on the forward depressing operation of the forward shift pedal (3F) and the reverse shift pedal. (3R) is provided with a relay shaft (31) interlocking in the reverse rotation direction based on the forward depression operation, and the forward / reverse rotation of the relay shaft (31) is interlocked with the trunnion shaft (29) of the hydraulic pump (23). A work vehicle characterized in that it is configured accordingly.   A detecting device (34) for detecting forward / reverse rotation of the relay shaft (31) is connected to the relay shaft (31) interlocked with forward / reverse rotation by depressing operation of the forward shift pedal (3F) and depressing operation of the reverse shift pedal (3R). The work vehicle according to claim 1, wherein the work vehicle is provided with a structure in which the forward / reverse rotation motor (35) is interlocked in a predetermined manner and the trunnion shaft (29) is interlocked based on a detection result of the detection device (34).   3. The neutral position holding means is configured on the relay shaft (31) that is linked to forward and reverse rotation by depressing the forward shift pedal (3F) and depressing the reverse shift pedal (3R). The work vehicle described.

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