JP2909243B2 - Work vehicle braking operation structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake operation structure for a working vehicle equipped with a continuously variable transmission for traveling.

[0002]

2. Description of the Related Art An example of a work vehicle as described above is disclosed in Japanese Unexamined Patent Publication No.
-190553. The continuously variable transmission for traveling of the work vehicle (1 in FIG. 1 in the above-mentioned publication) is biased toward a neutral stop position (N in FIG. 1 in the above-mentioned publication), and performs a shift operation with a shift pedal. Is configured to do so. A lock mechanism (15 in FIG. 2 of the above-mentioned publication) capable of holding the continuously variable transmission at an arbitrary shift position is provided, and during work traveling at a constant speed, the continuously variable transmission is held at a desired shift position. It is configured so that work traveling can be performed. Further, a pair of side brakes capable of independently braking the left and right traveling wheels and a pair of brake pedals for operating the side brake (23a and 23b in FIG. 2 of the above-mentioned publication)
Is provided.

[0003] As described above, during work traveling while the continuously variable transmission is held at a desired shift position by the lock mechanism,
In the case where the vehicle turns with braking on one of the wheels, even if one brake pedal is depressed as shown in FIG. 2 of the above-mentioned publication, the linking member (26 in FIG. 2 of the above-mentioned publication) only tilts. The lock mechanism is not operated to the release side. Conversely, when both brake pedals are depressed at the same time, such as when the body is stopped, the linking member moves as a whole, and the lock mechanism is operated to the holding release side.

[0004]

As described above, the lock mechanism of the continuously variable transmission is held depending on the operation state of the pair of brake pedals (whether only one operation step or both operation steps are performed simultaneously). In the structure operated on the release side, in the structure described in the above-mentioned [Prior Art], the link member (26 in FIG. 2 in the above publication) for operating the lock mechanism on the release side and the brake pedal are connected to the elongated hole. (Fig. 2 of the above publication)
The lock mechanism is operated to the holding release side by utilizing the flexibility of the long hole by cooperating with each other through 26a, 26b, 26c).

[0005] In such a structure in which the long holes are used frequently, the sum of the mechanical errors generated in the long holes becomes relatively large, so that a malfunction may occur after long-term use. The present invention relates to a brake operation structure for a work vehicle, wherein a structure for operating a lock mechanism of a continuously variable transmission to a holding release side according to a depressed state of a pair of brake pedals is configured to operate reliably with few malfunctions. It is an object.

[0006]

SUMMARY OF THE INVENTION A feature of the present invention is that a continuously variable transmission for traveling biased to a neutral stop position side, and that the continuously variable transmission can be held and released at any shift position. The brake operation structure of a working vehicle provided with a lock mechanism and a pair of side brakes capable of independently braking each of the right and left traveling wheels is configured as follows. A pair of brake pedals for the side brake operation are arranged close to each other on the left and right, and a pair of link members are swingably attached to each of the pair of brake pedals to pivotally connect the distal ends of the pair of link members. At the same time, when the operating member is arranged in a range overlapping with the passing locus of the distal end portion of the pair of link members when the pair of brake pedals are simultaneously depressed, and only one of the pair of brake pedals is depressed, one of the By the depressing operation of the brake pedal, the link member of the other brake pedal that is not depressed is swung around a swing fulcrum with the other brake pedal that is not depressed, and the distal ends of the pair of link members are laterally moved from the operating member. When the user moves and the operating members are not pushed by the tip portions of the pair of link members and the pair of brake pedals are simultaneously depressed, The push of the link member operating member by the distal end of the operation, and coordinate the operation member and the locking mechanism as the locking mechanism is operated to the holding release side by the operation member.

[0007]

According to the first aspect of the present invention, in a state where the traveling continuously variable transmission is held at a desired shift position by the lock mechanism and the vehicle is traveling, for example, as shown in FIG. When the stepping operation is performed, the link member 23 and the pivot point P2 of the one brake pedal 20 that is depressed move, while the pivot point P3 of the link member 23 of the other brake pedal 21 that is not depressed moves. And the link member 23 of the other brake pedal 21 that is not depressed is swung laterally around the swing fulcrum P3. Thereby, the pair of link members 2
The distal ends of the pair of link members 23 do not push the operating member 38 because the distal ends of the pair 3 are separated from the operating member 38 in the lateral direction. Therefore, the lock mechanism is not operated to the holding release side, and maintains the holding state of the continuously variable transmission.

On the other hand, when the pair of brake pedals 20 and 21 are simultaneously depressed at the time of stopping or the like, as shown in FIG. 1, the pair of link members 23 and the pivot points P2 and P3 move as they are. And a pair of link members 23
1 also moves from the state of FIG.
Press 8 to operate. Thereby, the lock mechanism is operated to the holding release side.

As described above, according to the features of claim 1,
Instead of the structure in which the lock mechanism is operated to the holding release side by utilizing the long hole flexibility as described in [Prior Art], three points of the link member (for example, the pivot points P2 and P2 in FIG. 1) are used.
3, and a pivotal support structure of the pair of link members 23), and does not have a play or the like due to a long hole. Thus, according to the first aspect of the present invention, mechanical errors caused by backlash and the like become small, and thus, there is little possibility of malfunction occurring even after long-term use.

When one of the brake pedals is depressed, the link member of the other brake pedal that is not depressed is swung laterally around the swing fulcrum, and the distal ends of the pair of link members are moved laterally from the operating member. It is in a state of leaving. Therefore, even if a mechanical error occurs in the pair of link members, the point at which the distal ends of the pair of link members are laterally separated from the operation member as described above depresses one brake pedal. In doing so, there is no possibility that the operating member is erroneously pushed by the pair of link members.

[0011]

According to a first aspect of the present invention, there is provided a brake operation structure of a working vehicle having a structure for operating a lock mechanism of a continuously variable transmission to a holding release side depending on a state of a stepping operation of a pair of brake pedals. It can be configured so that mechanical errors that occur even after long-term use are small,
The operation can be reliably performed with less operation failure, and the reliability and durability of the working vehicle can be improved.

According to the first aspect of the present invention, even if a mechanical error occurs in the pair of link members, one of the brakes is provided by the point that the distal ends of the pair of link members are laterally separated from the operation member. Since there is no possibility that the operating member is erroneously pushed when the pedal is depressed, the reliability of the operation of the work vehicle can be improved in this aspect as well.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 9, an engine 3 is provided at a front portion of a body supported by front wheels 1 and rear wheels 2 (corresponding to traveling wheels), a control section 4 is provided at the center of the body, and a transmission case 5 is provided at a rear portion of the body. An agricultural tractor, which is an example of a work vehicle, is configured.

As shown in FIGS. 4 and 9, a transmission case 5 at the rear of the fuselage is provided with a hydrostatic type continuously variable transmission 6 (corresponding to a continuously variable transmission for traveling) for traveling. Next, the operation structure of the hydrostatic type continuously variable transmission 6 will be described. As shown in FIG. 8, the hydrostatic type continuously variable transmission 6
The operating shaft 7 protrudes laterally from the swash plate (not shown), the first operating plate 8 and the second operating plate 16 are fixed to the operating shaft 7, and the forward shift pedal 9 and the reverse shift pedal 10 Is fixed to the second operation plate 16.

As shown in FIG. 8, a V-shaped operation arm 12 is swingably movable around a horizontal axis P 1 of the transmission case 5.
Are supported, and the roller 1 at one end of the operation arm 12 is supported.
4 is applied to the lower surface of the first operation plate 8. Spring 1
5, the operation arm 12 is urged upward and the spring 1
The first operation plate 8 is urged to the neutral stop position by the urging force 5.

This agricultural tractor is provided with a speed change lever 13 in addition to the forward and reverse speed change pedals 9 and 10. Next, the linkage between the speed change lever 13 and the operating shaft 7 of the hydrostatic type continuously variable transmission 6 is provided. The structure will be described. As shown in FIGS. 4 and 5, a support shaft 27 having an oval cross section and a partially cutout outer surface is rotatably supported by a fixed support plate 26 at the rear of the fuselage. The lever 13 is fixed. A friction plate 29 is externally fitted to the support shaft 27, and a cylindrical member 31 presses the friction plate 29 rightward on the paper by a spring 30 to hold the support shaft 27 and the shift lever 13 by friction. As described above, the friction plate 29 and the spring 30
The friction member 32 and the cylindrical member 31 constitute a friction holding type lock mechanism 32.

As shown in FIG. 5 and FIG.
Are provided with four sets of projections 31a, and the support plate 26 is provided with four sets of apertures 26a. As a result, the protrusion 31a
The friction plate 29 is pressed by the
The cylindrical member 31 does not rotate due to the engagement between the cylindrical member 31 and the opening 26a.

An operation arm 33 is fitted on the opposite side of the support shaft 27 so as to be relatively rotatable. As shown in FIGS. 4, 5 and 8, a push-pull is provided between the operation arm 33 and the second operation plate 16. A wire 34 is provided. An engagement member 35 is swingably mounted around the axis P4 of the support shaft 27, and a helical spring 36 for urging the engagement member 35 counterclockwise in FIG. A link rod 37 is attached to the arm portion 35a of the engagement member 35. The link rod 37 extends to near the upper end of the shift lever 13, and is an operation member 39 that can swing around the axis P5 of the shift lever 13. , A linkage rod 37 is attached. As shown in FIGS. 5 and 6, the guide member 4 is provided near the upper end of the shift lever 13 along the operating direction of the shift lever 13.
0 is fixed, and the operating member 39 is applied to the guide member 40 by the urging force of the helical spring 36.

The state shown in FIG. 5 and FIG.
3 is being operated to the neutral position N, and the shift lever 13 can be operated only in the range from the neutral position N to the forward side F, and cannot be operated to the reverse side. A spring 18 for urging the support shaft 27 and the shift lever 13 toward the neutral position N is attached to the arm 17 fixed to the support shaft 27. In this case, since the engaging member 35 is separated from the operation arm 33, the hydrostatic type continuously variable transmission 6 can be freely shifted to the forward side and the reverse side by the forward and reverse shift pedals 9 and 10.

The shift lever 1 is shifted from the state shown in FIGS.
When the operation member 3 is moved to the forward side F, the operation member 39 is pushed rightward in FIG. 5 by the guiding action of the guide member 40, and the engagement member 35 enters the passage locus of the operation arm 33. Then, the operating arm 33 is pushed by the engaging member 35 to perform the swinging operation, and the hydrostatic type continuously variable transmission 6 is operated to the forward high speed side. In this case, even if the hand is released from the shift lever 13 at the desired shift position, the shift lever 13 is held at the shift position by the holding action of the lock mechanism 32, and the aircraft corresponds to the shift position of the shift lever 13. It moves forward at a constant speed. If the forward shift pedal 9 is depressed in this state, the engaging member 35 is separated from the operation arm 33, and the speed can be increased to the predetermined speed or more. For example, the operation arm 33 comes into contact with the engagement member 35 and returns to the above-mentioned constant speed.

With the above-described structure, in a state where the shift lever 13 is held at a desired shift position on the forward side F, the shift lever 13 is directly returned to the neutral position N or the reverse shift pedal 10 is depressed. When the shift lever 13 is returned to the neutral position N via the push-pull wire 34, the engaging member 35 is automatically separated from the operation arm 33 by the urging force of the helical spring 36, and the shift lever 13 and the hydrostatic type stepless. The link with the transmission 6 is automatically released.

Next, the side brake 19 for traveling and FIG.
The relationship with the lock mechanism 32 shown in FIG. FIG.
As shown in FIG. 1, a pair of side brakes 19 that can independently brake the left and right rear wheels 2 are provided. As shown in FIGS. 3 and 1, a pair of brake pedals 20 and 21 are supported side by side around a horizontal axis P <b> 6 of the control section 4 so as to be swingable, and a pair of side brakes 19 and a pair of brake pedals 20 are provided. , 21 are linked to each other by a link rod 22. A spring 28 for urging the pair of brake pedals 20, 21 toward the brake release side is attached.

As shown in FIGS. 1 and 3, the axes P2 and P3 (corresponding to the swing fulcrum) which are substantially perpendicular to the stepping operation direction (vertical direction in the drawing) of the pair of brake pedals 20 and 21.
A pair of link members 23 that can swing freely are attached to the lower surfaces of the pair of brake pedals 20 and 21, respectively. The tips of a pair of link members 23 are pivotally connected by pins 24, and rollers 25 are attached to the pins 24. Below the pair of brake pedals 20, 21,
The operating member 38 is supported so as to swing downward from the position shown in FIG. 3 around the horizontal axis P7, and is provided with a helical spring 41 for urging the operating member 38 upward. An operation member 38a having a mountain shape in a vertical front view is an operation member 38.
In a state where the pair of brake pedals 20 and 21 are not depressed as shown in FIG. 1, the rollers 25 of the pair of link members 23
8a is set at the upper end of the mountain shape.

As shown in FIGS. 4 and 5, the hydraulic oil from the charge pump 42 of the hydrostatic type continuously variable transmission 6 is supplied to the cylindrical member 31 of the lock mechanism 32 via the switching valve 43.
Is configured to be supplied to the oil chamber 31b. The switching valve 43 is urged by a spring 43a toward the first position 43A for draining the hydraulic oil from the oil chamber 31b. Normally, the shift lever 13 is held by the action of the spring 30 shown in FIG. ing. As shown in FIGS. 3 and 4, the operation member 38 and the switching valve 43 are linked and connected by a link mechanism 44.

With the above-described structure, in a state where the shift lever 13 is held at a desired shift position on the forward side F by the lock mechanism 32 and the vehicle is traveling, one brake pedal 20 is used, for example, when making a small turn. Is operated. When one of the brake pedals 20 is depressed in this manner, the link member 23 and the shaft center P2 of the depressed brake pedal 20 move downward as shown in FIG. The axis P3 of the link member 23 of the brake pedal 21 remains at that position, and the link member 23 of the other brake pedal 21, which is not depressed, swings laterally around the axis P3. Thereby, the roller 25 at the tip of the pair of link members 23 moves from the position shown in FIG. 1 along the right upper surface of the operation unit 38a diagonally downward and rightward on the paper, and the operation member 38 moves downward. Is not pressed. Therefore,
The lock mechanism 32 shown in FIG. 5 is not operated on the holding release side,
The holding state of the speed change lever 13 is maintained.

A pair of brake pedals 2 such as when stopped
It is assumed that both 0 and 21 are operated simultaneously. In this case, the pair of link members 23 and the shaft cores P2 and P3 move downward from the state shown in FIG. 1, and the roller 25 also moves downward from the state shown in FIG. Press to. Thereby, the switching valve 43 shown in FIG. 4 is operated to the second position 43B by the operation of the link mechanism 44, and the hydraulic oil from the charge pump 42 is
The cylinder member 31 is supplied to the oil chamber 31b of the cylindrical member 31 in FIG. 2, and the cylindrical member 31 is slid to the left in FIG. Thereafter, the shift lever 13 is returned to the neutral position N by the urging force of the spring 18, and the hydrostatic type continuously variable transmission 6 is returned to the neutral stop position by the urging force of the spring 15 shown in FIG.

As shown in FIG. 2, the operation section 38a has a relatively wide left and right width. This is because, for example, when the brake pedal 20 starts depressing the one brake pedal 20 and then slightly depresses the other brake pedal 21 at the time of stopping as described above, the roller 25
1 is slightly shifted right or left from the position shown in FIG.
Is to be pushed downward. In the above embodiment, a belt type continuously variable transmission may be provided in place of the hydrostatic type continuously variable transmission 6.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a front view of the vicinity of a pair of brake pedals and a link member.

FIG. 2 is a front view of the vicinity of the link member when the brake pedal on the left side of the drawing is depressed from the state shown in FIG. 1;

FIG. 3 is a side view showing the vicinity of a pair of brake pedals and a link member;

FIG. 4 is a schematic diagram showing a linked state of a hydrostatic type continuously variable transmission, forward and reverse shift pedals, a shift lever, a lock mechanism, and a pair of brake pedals.

FIG. 5 is a vertical rear view of the vicinity of a shift lever and a lock mechanism.

FIG. 6 is a plan view of the vicinity of a shift lever and a guide member.

7 is a longitudinal sectional side view of the vicinity of a cylindrical member and a friction plate of the lock mechanism in FIG. 5;

FIG. 8 is a side view of the vicinity of a forward / reverse speed change pedal.

FIG. 9 is an overall side view of the agricultural tractor.

[Explanation of symbols]

 2 Wheel 6 Continuously variable transmission 19 Side brake 20, 21 Brake pedal 23 Link member 32 Lock mechanism 38 Operating member P2, P3 Swing fulcrum

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60K 41/26 B60T 7/00 B60K 41/24

Claims (1)

(57) [Claims] 1. A continuously variable transmission device for traveling, which is biased to the neutral stop position side (6), the continuously variable transmission (6) of any
Holding and held in the shift position releasing operably locking mechanism (3
2) and a brake operation structure of a working vehicle including a pair of side brakes (19) capable of independently braking each of the right and left traveling wheels (2), wherein the operation of the side brake (19) is performed. a pair of brake pedals use (20), arranged close to the left and right (21), one
The pair of link members (23) are connected to the pair of brake pedals.
(20) and (21) are swingably attached to each other to pivotally connect the distal ends of the pair of link members (23) and to simultaneously operate the pair of brake pedals (20) and (21). The pair of link members when the stepping operation is performed (23)
The operating member (38) is arranged in a range overlapping with the passage locus of the tip of the brake pedal , and the pair of brake pedals (20) and (21)
When only one of the brake pedals is operated,
No stepping operation is performed by the stepping operations (20) and (21).
Of the other brake pedal (20), (21).
The brake member (23) is connected to the other brake that is not stepped on.
Pivot point (P2) with key pedals (20) and (21),
(P3) swinging around, and the pair of link members (23);
Is moved laterally from the operating member (38).
The distal ends of the pair of link members (23)
If the pair of brake pedals (20) and (21) are simultaneously depressed without operating the operating member (38), the tip of the pair of link members (23) pushes the operating member (38). A brake operation structure for a working vehicle in which the operation member (38) and the lock mechanism (32) are linked so that the operation member (38) is operated and the lock mechanism (32) is operated to the holding release side by the operation member (38).