JPH01218922A - Work truck - Google Patents

Abstract

PURPOSE:To safely perform turning on the slope ground by controlling a front wheel transmission impossible to be switched to an acceleration driving condition when an inclination sensor detects a car body tilting by not less than a preset angle. CONSTITUTION:A control lever 51 provides a front wheel acceleration restraining means 62. When the control lever is placed in the first control position 4WDI, an adapting part 63 is adapted to an upper surface of a hook metal 65, and operation from the first control position 4WDI to the second control position 4WDII is restricted. A solenoid SL connects its plunger 66 to the hook metal 65, and pulling it to be returned by actuating this solenoid SL in the first driving condition, the control lever 51 is automatically operated from the first control position to the second control position, switching a mode to the standard 4WD mode. Electrification to the solenoid SL is performed only when a switch SW is turned on or only when an inclination sensor 68 detects a tilt of the preset angle or more, preventing the mode from being switched to the front wheel acceleration mode.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides an increased speed drive state in which the rotational speed of the front wheels is set higher than that of the rear wheels, and a state in which the rotational speeds of the front and rear wheels are set at approximately the same speed. The present invention relates to a work vehicle provided with a front wheel transmission capable of switching between a standard drive state and a standard drive state, and configured to switch the front wheel transmission to an increased speed drive state when the left and right steering angle of the front wheels exceeds the set angle.

[Conventional technology]

In this type of work vehicle, for example, if the machine makes a sharp turn on a slope, a strong centrifugal force acts on the machine and there is a risk of it falling over. Under such conditions, the front wheel transmission and steering system must be linked. It is necessary to prevent the switching mechanism from operating.

Therefore, with conventional work vehicles,
As disclosed in the above publication, a mode selection lever for operating the switching mechanism is provided, and by manually operating this lever, there is a mode in which the front wheel transmission can be switched to an accelerating drive state and a mode in which it is not possible. It was possible to select from.

[Problem to be solved by the invention]

In a work vehicle configured as described above, the mode selection lever is configured to self-hold in the operated position, so it is easy to forget to check which direction the lever is operated, and the front wheel transmission There was a risk that the aircraft would make a sharp turn on a slope while in a mode that allows switching to an increased speed state, and an improvement was desired.

The present invention has been devised in view of these circumstances, and improves operational efficiency by preventing the front wheel transmission mechanism from switching to the accelerating drive state when the aircraft makes a sudden turn on a slope or on the ground. The purpose is to avoid the dangers caused by mistakes.

[Means to solve the problem]

The characteristic configuration of the present invention is that a tilt sensor is provided for detecting the tilt of the aircraft body, and when the tilt sensor detects a tilt of the aircraft body that is equal to or greater than a set angle, the front wheel transmission is disabled to switch to the speed-up drive state of the front wheel transmission. A speed increase check means is provided, and its functions and effects are as follows.

[For production]

In other words, if the work vehicle is located on a slope and the machine body is tilted,
The inclination angle sensor detects the inclination, and if the inclination is equal to or greater than the set angle, the front wheel speed increase check means automatically disables the front wheel speed change mechanism from switching to the speed increase drive state.

〔Effect of the invention〕

Therefore, even if the front wheel transmission is selected in a mode that allows switching to an increased speed state when the aircraft makes a sharp turn on a slope, it will no longer switch to an increased speed drive state, making it possible to turn safely. Became.

〔Example〕

As shown in Figure 7, a pair of left and right front wheels (1
), and a pair of left and right non-steering type rear wheels (2) that are drivable, and various working devices such as a row tiller are connected to the rear of the vehicle so that they can be raised and lowered. An agricultural tractor, which is an example of a working vehicle, includes a lift arm (3) and a power take-off shaft (4) that transmits power to a connected working device.

To enable steering operation of the front wheel (1), as shown in FIGS. 5 and 6, the handle (5) is equipped with a rotating shaft (6), a gear transmission mechanism (7), and a rotating shaft (8). The steering gear mechanism (9) is interlocked via the steering gear mechanism (9), and the pitman arm (11) attached to the steering mechanism (9) so as to swing around the axis (Pl) is connected to the tie rod (12).
) through the pair of front wheels (1) each knuckle arm (
13), and by rotating the handle (5), this operating force is transmitted to the front wheels (5).
1) A pair of front wheels (1) and a handle (5) are interlocked so that each swings around an axis (P2).

A mission case (14) forming the rear part of the traveling aircraft
), a transmission (15) for the front wheel (1) is installed at the front end of the
This transmission (15) is constructed as shown in FIGS. 1 and 4.

That is, a standard speed transmission gear (18) with a clutch pawl (18a) interlocked with a front wheel output gear (16) of a driving transmission (not shown) via a gear (17).
and a rotating shaft (19) and a gear (20) to the gear (17).
) is attached to the output shaft (23) so as to be able to rotate relative to the speed increasing transmission gear (22) with a multi-disc friction clutch (21), and a sleeve (24) fitted externally with splines is attached to the output shaft (23). ) is attached with a transmission member (25) that can rotate and slide integrally and also serves as a transmission.

A shifter (26) for slidingly operating the transmission member (25) is slidably attached to the transmission case (14) via a support shaft (27), and the shifter (26) is slidably attached to the transmission case (14) via a support shaft (27).
26) to the first operating position (S), the transmission member (
25) is capable of engaging and disengaging from the clutch pawl (18a) and is integrally rotatably engaged with the standard speed transmission gear (18) via the latch pawl (25a), so that the average circumference of the pair of front wheels (1) is The standard four-wheel drive state is established in which transmission is made to the front wheel differential mechanism (28) so that the speed and the average circumferential speed of the pair of rear wheels (2) are the same or almost the same, and the shifter (26) is operated in the second operation. When operated to position (N), the transmission member (25) disengages from the standard speed transmission gear (18) and also engages the friction clutch (21).
), and the pair of rear wheels (2
) is driven and the pair of front wheels (1) are in an idle state, resulting in a two-wheel drive state in which transmission to the front wheels (1) is cut off, and the shifter (26) is moved to the third operating position (H). When operated, the speed change member (25) engages and operates the friction clutch (21) using the operation part (25b), and the speed increasing transmission gear (
22), and the pair of front wheels (1)
The vehicle is set to an increased speed drive state in which power is transmitted to the front wheel differential mechanism (28) so that the average circumferential speed of the rear wheels (2) is greater than the average circumferential speed of the pair of rear wheels (2). In other words, the shifter (26
) The sliding operation of the transmission member (25) in conjunction with the operation of the gear shift member (25) causes the two-wheel drive state to be switched to the three states described above.

A swinging arm (29) whose free end is engaged with the shifter (26) and a rotary cylinder shaft (30) penetrating the transmission case (14) can be interlocked with the shifter (26);
and the mission case (14) of the rotating sleeve (30).
As shown in FIG. ), and this spring (33) moves the shifter (26) to the first position.
It is biased to the operating position (S). The swing arm (29), the rotary cylinder shaft (30), the interlocking tool (31), and the rotary cylinder shaft (3o) are rotatably passed through the transmission case (14), and Interlocking tool (31) of the engaging part (34a) for the interlocking tool (31)
a rotating shaft (34) positioned relative to the mission case (14) by the impact against the mission case (14) and the impact of the plastic collar (35) against the mission case (14);
, swing arm (36), release wire (37), interlocking rond (38), spring (39), front wheel of the traveling aircraft is attached to the frame (40) so that it swings around the axis (P3). The front wheel (1) and the handle (5) are controlled by the swinging arm (41) and the cam mechanism (42), respectively.
the pitman arm (11) as an interlocking member;
An interlocking mechanism (43) with the shifter (26) is configured. As shown in FIG. 5, the cam mechanism (42) includes a cam plate (44) bolted to the pit muff 7-4 (11).
The cam groove (45) formed by the swing arm (
The roller (41) is fitted into the cam groove (45) while being attached to the shaft (46) so as to swing integrally therewith.
47), and as shown by the solid line in Fig. 5, the pitman arm (1
1), the inner portion (45a) of the cam groove (45) acts on the roller (47) and the spring (33)
) to position the swinging arm (41) in the first mounting position (R) and position the shifter (26) in the first operation position (S); Fifth
As shown by the imaginary line in the figure, the pitman arm (11) is located on the left or right side of the aircraft beyond the set swing range (L).
When the cam groove (45) swings tJJ, the outer part (45b) of the cam groove (45)
) or (45c) acts on the roller (47), and the swinging force of the pitman arm (11) causes the swinging arm (41) to
To install the second shifter (26), swing it to position (F).
) to the third operating position ()l). That is, when the steering angle of the front wheels (1) is less than the set value, the transmission (15) is in the standard four-wheel drive state, and the front wheels (1) are not steered beyond the set value. Then, the transmission device (15) is automatically switched to the speed-up drive state.

The interlocking tool (31) is configured to slide for spline engagement with the rotary cylinder shaft (30) located closer to the shifter (26), and with this sliding, the engagement tool Engages with the joint part (34a) so as to be integrally rotatable,
It is constructed so that it can be relatively rotated. and,
As shown in FIGS. 1 and 3, the support shaft (48) and the attachment to the mission case (14) are the first shaft center (P, ) and the second shaft center (P, ), and the interlocking tool operating member (50) is mounted so as to swing around each of the tools (49), and the interlocking tool operating member (50) is mounted to swing relative to the transmission case (14) around the first axis (P4) together with the tool (49). The operation lever (51) is slidably inserted into the cylindrical body 52) which is connected to ) are connected with pins so as to be relatively swingable, and the transmission (15) and the interlocking mechanism (43) are switched by rotating and sliding the interlocking tool (31) by manual operation of the operating lever (51). The operating mechanism is configured to perform the following operations. That is,
Is the guide (54) for the operating lever (51) formed so as to act on the protrusion (51a) of the operating lever (51)? As the operating lever (51) is raised and lowered along the vertical groove portion (55a) of g (55), the interlocking tool operating member (50) swings around the second axis (P,). The interlocking tool (31) is slidably operated with respect to the rotary cylinder shaft (30), and the horizontal groove portion (5
5b), the interlocking tool operating member (50) swings around the first axis (P4) to press and rotate the interlocking tool (31). , the interlocking tool (31) is allowed to be rotated by the spring (33). To elaborate further,
When the operating lever (51) is operated to the first operating position (4WD I), the interlocking tool (31) engages with the rotating shaft (34) as shown in FIG. 1, and the interlocking mechanism (43) becomes interlocked. , and the shifter (2) by the pitman arm (11)
Place the interlocking tool operating member (5) in a position that allows the switching operation of (6).
0) swings, and the transmission (15) moves to the pitman arm (
11), the front wheel speed-up four-wheel drive mode is established in which the front wheels can be switched between the standard four-wheel drive state and the speed-up drive state. Then, move the operating lever (51) to the second operating position (
When operated in 4WD II), the interlocking tool (31) separates from the rotating shaft (34), the interlocking mechanism (43) becomes uninterlocked, and the shifter (26) is moved by the spring (33).
As a result, the first operation position (S) is reached and the transmission (15) enters the standard four-wheel drive mode in which the transmission device (15) is maintained in the standard four-wheel drive state. Then, when the operating lever (51) is operated to the third operating position (2WD),
The interlocking tool (31) is detached from the rotating shaft (34), the interlocking mechanism (43) is in a non-interlocking state, and the shifter (26)
the interlocking tool (31) so that it is in the second operating position (N).
The interlocking tool operating member (50) swings to a position where it is pressed against the spring (33), and the spring plate (56) releasably holds the operating lever (51) at the third operating position (2WD). ), the interlocking tool operating member (50) swings into a locked state in which the interlocking tool (31) is received and supported so that the shifter (26) maintains the second operating position (N), and the transmission device ( 15) becomes the two-wheel drive mode in which the two-wheel drive state is maintained.

In addition, the operation cover (61) that houses the interlocking tool (31)
is equipped with a spring (69) that biases the interlocking device (31) in the direction of separating from the rotating shaft (34), so that the transmission (15) is maintained in the standard four-wheel drive state. The operating lever (51) is biased downward.

The operation lever (51) is provided with a front wheel speed increase check means (26).
is provided. To explain specifically, the operation lever (51
) is provided with an abutting portion (63) near the protrusion (51a) of the fender (6
4) is provided with a latch (65), and this latch (65) is biased to protrude toward the operating lever (51). Then, when the operation lever (51) is operated upward, the abutment part (63) is moved to the latch (6).
5) and push back the latch (65) so that operation to the first operation position (4WD I) is permitted, and operation to the first operation position (4WD I). Then, the contact part (63) comes into contact with the top surface of the latch (65), and the operation from the first operation position (4WD I'') to the second operation position (4W[I II) is restricted. A plunger (66) of a solenoid (SL) provided on the fender (64) side is connected to the latch (65), and in the first drive state, this solenoid (SL)
The latch (65) is pulled back by activating the
The operating lever (51) is automatically operated from the first operating position (4WD I) to the second operating position (4WD II') to switch to the standard four-wheel drive mode.

The solenoid (SL) is energized when the switch (SW) provided in the driving section (67) is turned on, or when the tilt sensor (68) provided at the rear of the driving section (67) is turned on.
This is done only when the system detects a tilt of the aircraft from front to back and from side to side that exceeds the set angle. In other words, the front wheel speed increase restraining means (62) is intended to prevent the front wheels from entering four-wheel drive mode when turning the aircraft on a slope, and to prevent sudden centrifugal force from acting on the aircraft. be.

The bolt (32) is fitted with a stopper (57) as shown in FIG. 4, which is engaged with the rotary cylinder shaft (30) so as to suppress sliding of the rotary cylinder shaft (30) with respect to the mision case (14). ) is fixed to the transmission case (14) in cooperation with the lock nut (58). The head of the pole l-(32) is provided with a stopper portion for the interlocking tool operating member (50), and a portion of this stopper moves the shifter (26) to the second operating position (
N) The interlocking device operating member (50) is operated to
to move the shifter (26) to the second operating position (N
) The bolt (32) is arranged so as to be positioned at the position.

Front wheel speed increase check means (62) explained in this example
is applied to an agricultural tractor configured as described above. Therefore, the solenoid (SL) is connected to the operating lever (51), and the operating lever (51) is energized.
1) may be forcibly pulled downward to the second operation position (4WD [+). In addition, the transmission device (15) includes a hydraulic front wheel speed increasing clutch and a standard drive clutch.
It is equipped with an electromagnetic valve that selectively operates these clutches, and is also equipped with a steering angle sensor that electrically detects the steering angle of the front wheels (1). In agricultural tractors that are configured to operate the electromagnetic pulp control device based on the detection signal from the steering angle sensor, when the control device receives the detection signal from the tilt sensor, the control device ignores the detection signal from the steering angle sensor. By doing so, the front wheel speed increase check means can be replaced with electrical processing.

Alternatively, the tilt sensor (68) may be configured to detect only the longitudinal or horizontal tilt of the aircraft body.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the working vehicle according to the present invention, FIG. 1 is a longitudinal sectional front view showing the operation structure of the front wheel speed increasing device and the front wheel speed increasing check means, and FIG. 2 is a cross section taken along the line ■-■ in FIG. 1. Figure 3 is the first
4 is a sectional view taken along the line rV-IV in FIG. FIG. (1)...Front wheel, (2)...Rear wheel, (
15)...Front wheel transmission, (62)...
・Front wheel speed increase check means, (68)...(circle tilt sensor)

Claims (1)

[Claims] A speed-up drive state in which the rotation speed of the front wheel (1) is set higher than the rotation speed of the rear wheel (2), and the front and rear wheels (1) and (2).
A front wheel transmission (15) is provided that can switch between a standard drive state in which the rotational speeds of the front wheels (15 and 15) are set at approximately the same speed.
The work vehicle is configured to switch the front wheel transmission (15) to an increased speed drive state when the left and right steering angle of the machine body ( ) exceeds a set angle, and the work vehicle includes a tilt sensor (
68), and when this tilt sensor (68) detects a tilt of the aircraft by a set angle or more, the front wheel transmission (15)
A work vehicle is provided with a front wheel speed increase check means (62) that makes it impossible to switch to a speed increase drive state.