JP2528724Y2 - Work vehicle accelerator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a working vehicle such as a crane truck or an aerial work vehicle. More specifically, the present invention relates to a hydraulic pump driven by an engine and a discharge oil from the hydraulic pump. The present invention relates to an accelerator control device for a working vehicle, in which hydraulic actuators for various operations are actuated, and the speed of the operation can be controlled by controlling the engine speed.

(Prior art) A typical example of this type of work vehicle is a vehicle-mounted crane. Conventional vehicle-mounted cranes include an operation lever for operating various cranes (a valve operation lever for operating a hydraulic switching valve to a hydraulic actuator). Some of them have a so-called auto-accelerator function in which an accelerator operation can be performed in conjunction with the operation of (1). In a conventional working vehicle having such an auto accelerator function, when a valve operating lever is operated, as shown in FIG. 18, a corresponding switching valve is opened and, at the same time, an accelerator is blown and engine rotation is started. The numbers are getting higher. Further, the speed of the hydraulic actuator is determined by the opening degree of the switching valve and the engine speed. As the operating stroke of the valve operating lever increases, the opening degree of the switching valve increases and the engine speed also increases. The action increases the operating speed change rate of the hydraulic actuator. The operating stroke of the valve operating lever is a relatively small range up to the end of the stroke of the switching valve, and the engine speed can be increased from the idling state to a desired high speed within the small operating stroke. Is set to

However, with a conventional auto-accelerator type work vehicle, depending on the type of work, there is a case where it is not necessary to increase the engine speed so much or a case where it is desired to perform the work at a low speed. When the valve operating lever is operated, the engine speed becomes unnecessarily high as a result, and there arises a problem that the operating speed becomes unnecessarily high in addition to the loss of fuel efficiency and the generation of noise. In addition, the operable range of the valve operating lever is a relatively small range up to the end of the valve stroke, and the operation of the valve operating lever simultaneously increases the opening of the switching valve and the engine speed. Due to their synergistic effect, the rate of change in working speed increases, so even a small amount of lever operation causes the working speed to change significantly,
There is a problem that it is necessary to use a great deal of nerves to operate the valve operating lever, and it is difficult to adjust the working speed to a fine movement state.

Further, among known auto-accelerator-type working vehicles, for example, as shown in Japanese Utility Model Application Laid-Open No. 61-25389, the operating range of a valve operating lever is set to a first operating position at which a switching valve is fully opened (stroke end). Can be operated up to the overstroke range beyond the above, and even if the valve operating lever is operated, it does not interlock with the accelerator until the switching valve reaches the stroke end, but interlocks with the accelerator when the valve operating lever is operated to the overstroke range There are things that I try to do. However, in the accelerator control device of this known example (Japanese Utility Model Laid-Open No. 61-25389), as shown in FIG. 19, the opening operation timing of the switching valve and the engine rotation speed increasing timing are set so as not to overlap. Therefore, the rate of change in speed increase of the hydraulic actuator with respect to the amount of operation of the valve operation lever is moderate, but even when work can be performed with the engine speed low, the valve operation lever is inadvertently moved to the maximum stroke position. When operated, the engine starts to blow up to the maximum number of revolutions. In this case, it is necessary to operate the valve operating lever while using considerable nerves.

(Purpose of the Invention) In view of the above-mentioned problems of the conventional accelerator control device, the present invention is directed to an auto-accelerator type in which the accelerator operation device is interlocked with the operation of the valve operation lever. It is possible to arbitrarily adjust the accelerator blow-up timing and the maximum engine speed with respect to the operation amount of the engine as required, so that the engine does not exceed the desired engine speed even when the valve operating lever is operated to the maximum. It is an object of the present invention to provide an accelerator control device as described above.

(Means for Achieving the Object) The present invention provides an accelerator operating device for increasing / decreasing the number of revolutions of an engine, a hydraulic pump driven by the engine, and a hydraulic actuator operating by receiving oil discharged from the hydraulic pump. A switching valve for switching the supply of the discharge oil to the hydraulic actuator, a valve operating device for switching the switching valve, and an interlocking operation of the valve operating device and the accelerator operating device in a predetermined operation area of the valve operating device. A work vehicle provided with a mechanism, wherein the interlocking mechanism comprises a shaft which is turned by operation of a valve operating lever of a valve operating device, and a cylinder which is fitted outside the shaft so as to be rotatable and movable back and forth in the axial direction. And an accelerator operation link for varying the engine speed by rotating the cylinder portion, and the shaft is rotated. The engagement portion and the engagement receiving portion, which are engaged with each other when they are engaged to rotate the cylinder with the shaft, are disposed on the shaft side, and the engagement receiving portion is located on the cylinder portion side. The engagement portion when the shaft is rotated with respect to the cylinder portion in accordance with the amount of axial displacement of the cylinder portion relative to the shaft in one of the engagement portion and the engagement receiving portion. And an inclined engagement surface that can sequentially change the engagement position between the shaft and the engagement receiving portion in the circumferential direction of the shaft, and the cylindrical portion of the accelerator operation link is arranged in the axial direction with respect to the shaft. A reciprocating operation device for causing the reciprocating displacement to be performed.

(Action) According to the accelerator control device of the present invention, the advance / retreat operating device can move the accelerator operating link on the accelerator operating device side in the axial direction with respect to the axis rotated by the valve operating lever, When the accelerator operation link is displaced in the axial direction with respect to the shaft in such a manner, when the accelerator operation link is displaced in the axial direction with respect to the shaft, the tilting member provided on one of the engagement part on the shaft side and the engagement receiving part on the cylinder part side of the accelerator operation link. With the mating surfaces, the position at which the engagement portion engages with the engagement receiving portion can be changed in the circumferential direction of the shaft. When the engagement position between the engagement portion and the engagement receiving portion is changed in the circumferential direction of the shaft, the accelerator operation link starts rotating with respect to the shaft that is rotated when the valve operation lever is operated. The time to do it will change. This means that when the valve operating lever is operated, the switching valve is operated immediately, but the accelerator operating device can be operated with a delay, so that when the valve operating lever is operated to the final position. Even in this case, the upper limit of the engine speed can be limited to a desired engine speed. In other words, the advance / retreat operation device previously sets the axial advance / retreat position of the accelerator operation link to a desired position according to the work content.
The operation timing and the maximum operation amount of the accelerator operation device operated in conjunction with the operation of the valve operation lever can be adjusted to an appropriate state. The engagement position between the engagement portion and the engagement receiving portion in this interlocking mechanism is determined by the play (shaft) between the shaft and the cylindrical portion within a range in which the accelerator operation link can advance and retreat in the axial direction with respect to the shaft. From a state without circumferential play) (i.e., the accelerator operating device is operated simultaneously with the operation of the valve operating lever), a state in which the accelerator operating link does not rotate with the shaft even when the valve operating lever is fully operated (i.e., If the accelerator operation device is not operated over the entire operation range of the valve operation lever), the allowable adjustment range of the hydraulic actuator speed can be increased.

(Effects of the Invention) As described above, in the present invention, the operation timing and the operation amount of the accelerator operation device operated in conjunction with the operation of the valve operation lever can be arbitrarily adjusted in advance by the advance / retreat operation device. According to the work content, for example, when work at high speed is required, set in a state where there is no play in the axial direction between the engaging portion and the engagement receiving portion, and conversely, work at low speed In a good case, it can be set with a large play in the axial direction between the engagement portion and the engagement receiving portion,
The engine speed can be adjusted according to the work content. In particular, when working at low speeds, operating the forward / backward operation device to limit the maximum engine speed allows the engine speed to be higher than necessary even when the valve operating lever is operated up to the maximum stroke. There is an effect that it is no longer blown up. Further, when the work is performed in a state where the maximum engine speed is limited to a low engine speed according to the work content, the engine speed does not blow up more than necessary as described above, so the valve operation is performed. There is also an effect that it is not necessary to use much nerve for operating the lever.

(Embodiments) Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. FIGS. 1 to 11 show the first embodiment of the present invention and FIGS. 12 and 13 show the same. Second Embodiment FIGS. 14 to 17 show an accelerator control device for a working vehicle according to the third embodiment.

The accelerator control device of the first embodiment shown in FIGS. 1 to 11 is applied to a work vehicle equipped with an auto accelerator mechanism, such as a crane truck or an aerial work vehicle. That is, this type of work vehicle includes various types of hydraulic motors such as a hydraulic motor for rotating the swivel, a hydraulic cylinder for extending and retracting the telescopic boom, a hydraulic cylinder for raising and lowering the telescopic boom, and a hydraulic motor for driving the winch (especially in the case of a crane truck). Hydraulic actuator 13
Is used. And in the working vehicle of this embodiment,
As shown in FIGS. 1 and 2, an engine 1 and an accelerator operation device 2 for increasing / decreasing an engine speed are provided.
A hydraulic pump 12 driven by the engine 1,
In addition, switching valves 14, 14,
An interlocking mechanism (auto-accelerator mechanism) 5 is provided so that the accelerator operation device 2 can be operated in conjunction with the valve operation device 4 that controls the switching of.

The accelerator operating device 2 includes an accelerator operating link 21 pivotally supported by a shaft 49, and an accelerator control cable 18 connecting a lower end 21a of the accelerator operating link 21 and a lever 19a of an accelerator governor 19, The lever 19a of the accelerator governor 19 can be operated by tilting the accelerator operation link 21. The accelerator operation link 21 is connected to the valve operation lever 41 via the interlocking mechanism 5.
The interlocking mechanism 5 will be described later in detail.

In this embodiment, as shown in FIG.
Since a total of five (and five hydraulic actuators 13) are used, a total of five sets of valve operating devices 4 are used correspondingly. Each of the valve operating devices 4 has a pair of left and right valve operating levers 41, 41 whose base ends are pivotally supported by shafts 42, 42, respectively. Connecting rod 44 via link 43,43
And one link 43 is connected to the spool 14a of the switching valve 14. Each of the valve operation levers 41, 41 is disposed on each of the left and right sides of the base 11 of the vehicle.
Is operated (up and down operation) to switch the switching valve.
14 can be operated. A total of five valve operating levers 41, 41... On the same side on the left and right sides are pivotally mounted on common shafts 42, 42, respectively, in a state of being arranged in the vehicle front-rear direction in plan view (FIG. 1). And each of the shafts 42, 42
Are supports 15 that are fixed to the base 11 near each end
It is installed in support of.

The interlocking mechanism 5 is provided with a cam plate 31 provided at the base end of each of the left and right valve operation levers 41 (the right side in FIGS. 1 and 2), and swings by the respective cam plates 31. A swing member 32 to be operated, a shaft 49 serving as a swing center of the swing member 32, and a cylindrical portion provided on the accelerator operation link 21
22.

The swing member 32 is positioned at a position eccentric to the shaft 49 of the roller 33.
have.

The cam plate 31 is fixed to the base end of the valve operation lever 41, and can be swung right and left by an up-down tilt operation of the valve operation lever 41. Also, the cam plate 31
Are provided with two right and left cam surfaces 31a, 31a (see FIGS. 3 and 4) which are respectively raised and inclined outward.

As shown in FIG. 4, when the valve operating lever 41 is moved upward (state 41 ') or moved downward (state 41') from the neutral position, the cam plate 31 is moved to the position 31 '. Swing in the counterclockwise direction as indicated by
The cam plate 31 can be swung in the clockwise direction as indicated by 31 ". When the cam plate 31 is swung in either the left or right direction as indicated by reference numeral 41" or 41 ", the swing is made. Element
As shown in FIG. 4, reference numeral 33 'in FIG.
The shaft 49 is rotated in the counterclockwise direction about 49, so that the shaft 49 is also rotated by a predetermined angle. The swing angle of the swing member 32 is proportional to the amount of tilt operation of the valve operating lever 41, but in the illustrated example, the maximum swing angle α of the swing member 32 is shown.
Is about 40 °. Further, this swing member 32 is
As shown in the figure, the roller 33 is urged by a spring 34 to the side that comes into contact with the cam surface.

On the other hand, as shown in FIGS. 3, 5 and 7, the cylindrical portion 22 (provided on the accelerator operation link 21) has a hole at the upper and lower middle portion of the accelerator operation link 21. It is formed so as to penetrate 21 laterally. The accelerator operation link 21 is mounted in a state in which the tubular portion 22 is fitted outside the shaft 49 so as to be able to rotate and move forward and backward in the axial direction.

The shaft 49 of the swing member 32 and the cylinder 22 of the accelerator operation link 21 are engaged with each other when the shaft 49 rotates, and the cylinder 22 is pivoted.
An engagement portion 51 and an engagement receiving portion 52 acting to rotate with 49.
Are formed. In the first embodiment, an engagement portion 51 formed of an outward projection is formed on the shaft 49 side, while an engagement portion formed of a substantially U-shaped notch capable of engaging with the engagement portion 51 is formed on the cylindrical portion 22 side. A receiving portion 52 is formed. The engagement receiving portion 52 has an appropriate depth (for example, a depth of about 10 to 15 mm) in the axial direction of the cylindrical portion 22, and the engagement portion (projection) 51 on the shaft 49 side is (Notched) 52
Within the length range, the cylinder portion 22 can be relatively displaced in the axial direction within the length range (actually, the cylindrical portion 22 can be advanced and retracted in the axial direction with respect to the shaft 49).

Further, the engagement receiving portion 52 of the cylindrical portion 22 has, for example, an angle of about 30 ° at one side (the side on which the shaft 49 rotates when the valve operation lever 41 is operated). An inclined engagement surface 53 that is inclined only in a divergent shape is formed. This inclined engagement surface 53
When the shaft 49 rotates with respect to the cylindrical portion 22 in accordance with the amount of axial displacement of the cylindrical portion 22 with respect to the shaft 49, the engaging portion 51 on the shaft 49 engages with the cylindrical portion 22. The position of engagement with the receiving part 52 is
In the circumferential direction. For example, as shown in FIG. 5, when the position of the cylindrical portion 22 in the axial direction with respect to the shaft 49 is at a position where the entrance portion of the engagement receiving portion 52 corresponds to the engaging portion 51, the position shown in FIG. As described above, the engaging portion 51 on the shaft 49 can play within the range of the angle β (about 40 °) with the inclined engaging surface 53 of the engaging receiving portion 52 on the cylindrical portion 22 (in the non-engaged state). Conversely, as shown in FIG. 8, when the position of the cylindrical portion 22 in the axial direction with respect to the shaft 49 is such that the innermost portion of the engagement receiving portion 52 corresponds to the engagement portion 51, As shown in FIG. 9, the engaging portion 51 on the shaft 49 side is substantially engaged with the inclined engaging surface 53 of the engaging receiving portion 52 on the cylindrical portion 22 and both (the engaging portion and the inclined engaging surface) There is almost no play in between. Therefore, the fifth
As shown in FIG. 6 and FIG. 6, in the state where there is a play of the angle β between the engaging portion 51 and the inclined engaging surface 53, the valve operating lever 41 is operated to the maximum (reference numeral 41 ′ or 41 in FIG. 4). 8), the shaft 49 rotates only within the range of the play angle β, so that the cylindrical portion 22 does not rotate with the shaft 49. On the other hand, in FIGS. As shown, when there is no play angle between the engagement portion 51 and the inclined engagement surface 53, the cylinder portion 22 immediately rotates with the shaft 49 when the operation of the valve operation lever 41 is started.

The accelerator operation link 21 can be moved forward and backward with respect to the shaft 49 by the forward and backward operation device 6. In this embodiment, the advancing / retreating device 6 includes a slider 61 that slides in the axial direction around the outer periphery of the shaft 49 on the side opposite to the side on which the engagement receiving portion 52 is formed in the accelerator operation link cylinder 22, and the slider 61 is connected to the accelerator operation link. Pressing member to press to 21 side
64, a control lever 60 for pushing and pulling the pressing member 64, and a spring 67 for urging the accelerator operation link 21 toward the slider 61. Slider 61
Has inclined cam surfaces 62, 62 formed on the upper surface and the lower surface, respectively. On the other hand, the pressing member 64 has two plate members 65, 65 which can sandwich the slider 61 from above and below, and
The inclined surfaces 66, 66 which abut against the respective inclined cam surfaces 62, 62 of the slider 61 are formed in 65. Control lever 6
The base end portion of the control lever 60 is pivotally supported by a shaft 42 (same as the shaft of the valve operation lever 41), and the base end portion of the control lever 60 and the pressing member 64 are connected by a link 68. Note that, in this embodiment, the control lever 60 is
In the same manner as in the case of the above, there is a pair of right and left, each base end thereof is connected with a connecting rod 69 via a link 68,
The forward / backward operation device 6 can be operated from either the left or right side of the vehicle.

The advance / retreat operating device 6 is assembled as shown in FIGS. 5 to 7, and when the control lever 60 is located in the same figure (FIGS. 5 to 7), the pressing member 64 operates as a slider. Therefore, the accelerator operation link 21 is maintained at the retracted position by being biased by the spring 67. Then, from this state (the accelerator operation link retracted state shown in FIGS. 5 and 7), the control lever 60
When the tilting operation is performed in the counterclockwise direction in FIG. 6, the pressing member 64 moves forward and presses the slider 61 toward the accelerator operation link 21, and the accelerator operation link 21 is opposed to the spring 67 according to the control lever operation amount. In particular, when the control lever 60 is operated to the maximum operation position, the accelerator operation link 21 is advanced to the position shown in FIGS. In the most advanced state of the accelerator operation link 21 (the state shown in FIGS. 8 and 9), the innermost portion of the engagement receiving portion 52 is set at a position corresponding to the engagement portion 51. When the control lever 60 is returned from the position indicated by reference numeral 60 (the position shown by the solid line) shown in FIG. 9 to the position indicated by reference numeral 60 '(the position shown by the chain line), the pressing member 64 is retracted, and the accelerator operation link 21 and the slider 61 are moved.
Is pressed by a spring 67, and the accelerator operation link 21 is automatically pushed back to the retracted position shown in FIG.

In the figure, reference numeral 25 denotes a connecting rod 69 of the advance / retreat operating device 6.
The accelerator lever operation pin 25 is attached to the side of the accelerator operation link 21 when the control lever 60 is tilted in the clockwise direction from the state shown in FIG. It acts to rotate the accelerator operation link 21 in the counterclockwise direction in FIG. Therefore, although the accelerator control device of this embodiment is of the auto-accelerator type, the valve operating lever 41
It is possible to increase the engine speed by operating the control lever 60 without relating to the operation of.
Reference numeral 26 denotes a stopper for preventing the accelerator operation link 21 from being excessively rotated in the counter-blowing direction.

The accelerator control device of the first embodiment operates the control lever 60 of the forward / backward operation device 6 to an arbitrary position to immediately increase the engine speed in conjunction with the operation of the valve operation lever 41. It is possible to select between a case where the engine rotation speed is increased after the operation of the valve operation lever 41 and a case where the engine rotation speed is kept idling even when the valve operation lever 41 is operated over the entire stroke. .

First, when the engine speed is immediately increased in conjunction with the operation of the valve operating lever 41, the control lever 60 is raised from the position shown in FIGS. 5 and 6 in the rising direction as shown in FIGS. By operating in the left-hand direction (rotation in the left direction), the accelerator operation link 21 is advanced to a position where the innermost portion of the engagement receiving portion (notch) 52 corresponds to the engagement portion 51. In this case,
In FIGS. 10 and 11, the control lever 60
In the position Xo, when any one of the valve operating levers 41 is operated upward or downward from this state, the opening degree of the switching valve 14 corresponding to the valve operating lever 41 gradually increases and simultaneously the accelerator operation is performed. The operation of the link 21 is also started immediately. Accordingly, in this case, the engine rotation speed increases as shown by the rotation speed change line Na in FIG. 10 in accordance with the operation amount of the valve operation lever 41, and the valve operation at which the switching valve 14 has a stroke end is performed. In the maximum operating state of the lever 41, the engine speed is the maximum speed (sign
Of N ₄ to the height) becomes increased. Also, at this time, as the operation amount of the valve operation lever 41 increases, the opening degree of the switching valve 14 gradually increases, and at the same time, the engine speed also gradually increases. soars as indicated by the speed change line Pa, the switching valve 14 is to rise the hydraulic actuator speed at a maximum operating state of the valve operating lever 41 to the stroke end to the maximum speed (the height of the code P _4). In this case, it is suitable for the operation in which the hydraulic actuator 13 is operated at a high speed.

Next, when the control lever 60 is positioned at an appropriate position between the position shown by the solid line (the position of reference numeral 60) and the position shown by the dashed line (the position of reference numeral 60 ') in FIG. The play interval between the control lever 60 and the inclined engagement surface 53 is also reduced.
As you operate the valve operating lever 41 in, for example, at the position of the code X ₁ to X ₃₎ figure, gradually switching valve 14 is immediately gradually opened, the accelerator operating link 21 is engaged portion 51
Is not operated until it comes into contact with the inclined engaging surface 53, and after the engaging portion 51 comes into contact with the inclined engaging surface 53 (the valve operating lever 41 is, for example, denoted by reference numeral in FIGS. 10 and 11). V ₁ ~
When operated to the position of the V _3), further by operating the valve operating lever 41, the engine speed therefrom as shown by the change in line Nb~Nd the engine speed starts to increase, the maximum operation of the valve operating lever 41 In this state, the engine speed is limited to the heights of the symbols N ₃ , N ₂ , and N ₁ as shown in FIG.
In the figure, as shown by the speed change lines Pb to Pd, the hydraulic actuator speeds are respectively limited to the heights of P ₃ , P ₂ , and P ₁ in the maximum operation state of the valve operation lever 41. Become. In this case, it is suitable for the operation when the speed of the hydraulic actuator 13 may be medium.

Further, the control lever 60 is moved to the position shown in FIGS. 5 and 6, that is, the state in which the play interval between the engaging portion 51 and the inclined engaging surface 53 is maximized (when the control lever 60 is moved in FIGS. 10 and 11). code when X ₄ in in position) in operating the valve operating lever 41, the engine rotational speed even when operating the valve operating lever 41 to the maximum operating position V ₄ the height of the code No idling (Fig. 10 in ), And the speed of the hydraulic actuator 13 is also limited to the height indicated by Po in FIG.
In this case, it is suitable for work when the speed of the hydraulic actuator 13 may be low.

In this accelerator control device, the position of the control lever 60 is appropriately set according to the work content as described above, so that the maximum values of the engine speed and the hydraulic actuator speed can be limited, respectively. Even when the operation lever 41 is operated to the maximum operation state,
The engine speed does not become higher than necessary, and the maximum speed of the hydraulic actuator 13 can be limited to a speed according to the work content. In particular, when performing with the maximum value of the engine speed and the hydraulic actuator speed kept low,
Even if the valve operating lever 41 is suddenly operated greatly, the engine speed does not increase so much (or at all) and the hydraulic actuator speed does not increase suddenly.
The operation of the valve operation lever 41 does not require much nerve.

The second embodiment shown in FIGS. 12 and 13 shows a modification of the structure of the engagement portion and the engagement receiving portion. In the second embodiment, the structure is opposite to that of the first embodiment. The engaging portion 81 on the shaft 49 side is formed in a cutout shape with an inclined engaging surface 83, and the engaging receiving portion 82 on the accelerator operation link tube portion 22 is engaged with the inclined engaging surface 83 of the engaging portion 81. It is formed in a projection shape that fits. The accelerator control device according to the second embodiment can also obtain the same operation as that of the first embodiment.

The third embodiment shown in FIGS. 14 to 17 is a modification of the first embodiment, and the accelerator control operation of the third embodiment is performed when the valve operating lever 41 is operated. At first, the stroke of the switching valve 14 is ended, and thereafter, by further operating the valve operating lever 41, the accelerator operating device is operated. Specifically, one end 71a of a short-length connecting rod 71 is pivotally connected to one end 44a of the connecting rod 44 of the valve operating device 4, and the connecting rod 71
The two ends (71 b and 41 a) are connected via a spring 79 with a slight gap between the other end 71 b of the valve operating lever 41 and the base end 41 a of the valve operating lever 41. In the third embodiment, when the valve operating lever 41 is in the neutral position (position Vo in FIG. 17) shown in FIG. 14, the switching valve 14 is in the closed state, and the valve operating lever 41 is closed. Is operated from the position shown in FIG. 14 to the intermediate position shown in FIG.
The position of the code V ₅₎ of FIG. 17, switching valve 14 is stroke end is only operated length L connecting rod 44. At this time, the spring 79 is maintained in the expanded state without being compressed. In the range where the valve operation lever 41 is operated from the position shown in FIG. 14 to the position shown in FIG. 15, the cam surface 31a of the cam plate 31 is adjusted so that the swing member 32 is hardly rotated. Accordingly, the valve operating lever 41 is moved from the position shown in FIG.
In the range where the operation is performed up to the position shown in FIG. 15, the accelerator operating device 2 is operated regardless of the positional relationship between the engagement portion 51 and the engagement receiving portion 52 in the interlocking mechanism 5 of the first embodiment. Never. When the valve operating lever 41 is further operated from the position shown in FIG. 15, the connecting rod 44 and the connecting rod 71 are not further pulled, so that the cam 79 is further tilted while the spring 79 is compressed. And swinging the swing member 32 to rotate the shaft 49,
When the valve operating lever 41 is operated to the maximum operating position shown in FIG. 16, the shaft 49 is rotated from the original position in FIG. 14 by the angle θ.

The accelerator control device of the third embodiment also employs the interlocking mechanism 5 of the first or second embodiment, and operates the forward / backward operation device 6 to engage the engaging portion 51 with the engaging receiving portion. by previously adjusting the position of engagement and 52, the upper limit (FIG. 17 of the engine speed upper limit (first 17 Figure codes No~N ₄₎ and a hydraulic actuator velocity when the maximum operating the valve operating lever 41 Po ~ P ₄ ) can be limited respectively. In the accelerator control device according to the third embodiment, the valve operating lever
Although the operation stroke of the valve 41 is increased, the rate of change of the hydraulic actuator speed with respect to the operation amount of the valve operating lever 41 is reduced, and the speed adjustment of the hydraulic actuator is facilitated.

[Brief description of the drawings]

1 is a partial plan view of a working vehicle provided with an accelerator control device according to a first embodiment of the present invention, FIG. 2 is a front view of FIG. 1, and FIG. 3 is an exploded view of a portion A of FIG. FIG. 4 is a perspective view, and FIG.
FIG. 5 is a sectional view taken along line BB of FIG. 5, FIG.
FIG. 5 is a sectional view taken along line CC of FIG. 5, FIG. 7 is a sectional view taken along line DD of FIG. 6, FIG. 8 is a state change diagram of FIG. 5, and FIG. FIGS. 10, 10 and 11 are graphs showing the operation of the accelerator control device of the first embodiment, respectively. FIG. 12 is a partially exploded perspective view of the accelerator control device according to the second embodiment of the present invention, and FIG. 12 is a longitudinal sectional view of the accelerator control device shown in FIG. 12 in an assembled state, FIG. 14 is a partial sectional view of the accelerator control device according to the third embodiment of the present invention, and FIGS. FIG. 17 is a graph showing the operation of the accelerator control device of the third embodiment, and FIGS. 18 and 19 are graphs showing the operation of the conventional accelerator control device. DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Accelerator operation device 4 ... Valve operation device 5 ... Interlocking mechanism 6 ... Forward / backward operation device 12 ... Hydraulic pump 13 ... Hydraulic actuator 14 ... Switching valve 21 ... Accelerator operation link 22 ... … Cylinder part 32… Swing member 41… Valve operating lever 49… Shaft 51… Engagement part 52… Engagement receiving part 53… Tilted engagement surface 60… Control lever 81… Engagement part 82: Engagement receiving part 83: Inclined engagement surface

Claims (1)

(57) [Scope of request for utility model registration] An accelerator operating device (2) for increasing / decreasing the rotation speed of an engine (1), a hydraulic pump (12) driven by the engine (1), and oil discharged from the hydraulic pump (12). Hydraulic actuator (13) that operates upon receiving
A switching valve (14) for switching the supply of discharge oil to the hydraulic actuator (13), a valve operating device (4) for switching the switching valve (14), and a predetermined operating area of the valve operating device (4). An interlocking mechanism (5) for interlocking the valve operating device (4) with the accelerator operating device (2)
The interlocking mechanism (5) includes a shaft (49) that is rotated by operating a valve operating lever (41) of a valve operating device (4), and a shaft (49) provided outside the shaft (49). An accelerator operation link (21) having a cylindrical portion (22) fitted so as to be rotatable and capable of moving back and forth in the axial direction and varying the engine speed by rotating the cylindrical portion (22). And the shaft (49)
When they rotate, they engage with each other to move the cylinder (22) to the shaft (49).
The engaging portions (51, 81) of the engaging portions (51, 81) and the engaging receiving portions (52, 82) acting to rotate with the shaft (49)
Side, engagement receiving portions (52, 82) are provided on the cylindrical portion (22) side, respectively, and the engagement portions (51, 81) and the engagement receiving portions (52, 8) are further provided.
2) One of the two cylinders (2) with respect to the shaft (49)
The shaft (49) is connected to the cylinder (2) according to the amount of axial
2) Inclined position that allows the engagement position between the engagement portion (51, 81) and the engagement receiving portion (52, 82) when rotated relative to the shaft (49) to be sequentially changed in the circumferential direction. An engaging and disengaging device (6) which is provided with engaging surfaces (53, 83) and which displaces the cylindrical portion (22) of the accelerator operating link (21) in the axial direction with respect to the shaft (49). ), An accelerator control device for a work vehicle.