JP3382050B2 - Operation structure of friction type transmission clutch - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating structure of a friction type transmission clutch which is used for traveling and for transmitting to a working device.

[0002]

2. Description of the Related Art For example, in a transmission clutch for traveling, a transmission clutch and a clutch pedal (corresponding to an artificial operation tool) are linked to operate the transmission clutch to a transmission side and a transmission cutoff side. In this case, if the clutch pedal is operated and held between the transmission side and the transmission cutoff side, the transmission clutch becomes a half-clutch state, and the machine body travels slowly.

[0003]

In the half-clutch state of the transmission clutch as described above, since the transmission clutch transmits power while slipping, if the half-clutch state is mistakenly maintained continuously for a long time. , The transmission clutch may be seized. According to the present invention, in the operation structure of the friction type transmission clutch, it is possible to prevent a situation in which the half clutch state is mistakenly continuously maintained for a long time and the transmission clutch is seized. The purpose is to do.

[0004]

[1]

A friction type forward / reverse switching clutch and an artificially operated manipulator are provided, and a linkage mechanism that links the forward / reverse switching clutch and the artificial manipulator is provided to correspond to the operation position of the artificial manipulator. state, with a configuration such that the forward-reverse switching clutch is operated, the forward-reverse switching clutch
Discriminating means switch for detecting whether or not a half-clutch state
And the forward / reverse switching clutch in this half-clutch state
A pressure sensor for detecting an operating pressure, and the half-clutch state of the forward / reverse switching clutch is set according to the operating pressure detected by the pressure sensor on the basis of the detection by the determining means.
A check mechanism is provided for forcibly operating the forward-reverse switching clutch to the transmission interruption side when continuously maintained for a predetermined set time .

[2] In the structure of the above-mentioned [1], forward / backward switching is performed by the restraint means.
When the clutch is operated to the transmission disengagement side, the restraint means
An informing means is provided for informing that the forward / reverse switching clutch has been operated to the transmission interruption side.

[0006]

[Action]

[I] With the configuration described in [1] above, the transmission clutch is operated to the transmission side and the transmission cutoff side through the linkage mechanism by operating the manual operation tool, which is the normal state. Next, even if the operator operates the transmission clutch to the half-clutch state by the artificial operation tool and maintains the half-clutch state, the half-clutch state is continuously maintained for the set time if configured as in the above [1]. If maintained, the transmission clutch is automatically operated to the transmission interruption side by the restraining means. As a result, even if the operator accidentally maintains the manual operation tool at the position corresponding to the half-clutch state for a long time, seizure of the transmission clutch is prevented.

[II] When configured as in the above item [2],
As in the case of the configuration of the above [1], the "action" described in the above [I] is provided, and in addition to this, the following "action" is provided. As described in the previous section [I], when the operator holds the manual operation tool at the position corresponding to the half-clutch state, the operator automatically operates the transmission clutch to the transmission disengagement side. Since the transmission clutch is operated to the transmission cutoff side even though there is no feeling to operate the transmission clutch to the transmission cutoff side, the worker may misunderstand whether something is wrong. Therefore, if the notification means as in the above item [2] is provided, the transmission clutch is automatically moved to the transmission disengagement side by the check means in order to prevent the seizure caused by continuously maintaining the half-clutch state for a long time. Since the operator is informed of the operation, the operator does not have the above-mentioned misunderstanding.

[0008]

According to the first aspect of the present invention, in the operation structure of the friction type transmission clutch, even if the operator accidentally maintains the artificial operation tool at the position corresponding to the half-clutch state for a long time, The transmission clutch is automatically operated to the transmission cutoff side to prevent the seizure of the transmission clutch, and the durability of the transmission clutch can be improved.

According to the second aspect of the invention, as in the case of the first aspect, the above-mentioned "effect of the invention" is provided. According to the second aspect of the present invention, the operator is not informed that the transmission clutch has been automatically operated to the transmission interruption side by the restraining means, and the operator does not have a misunderstanding. It was possible to prevent erroneous operation.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (1) FIG. 1 shows the inside of a mission case 8 of a four-wheel drive agricultural tractor, in which power from an engine 1 is transmitted to a PTO via a transmission shaft 2 and a hydraulic multi-plate PTO clutch 3.
It is transmitted to the shaft 4. The power from the engine 1 is applied to the forward clutch 5 (corresponding to a transmission clutch) or the reverse clutch 6
(Corresponding to transmission clutch), cylindrical shaft 7, main transmission 10,
It is transmitted to the left and right rear wheels 14 via the first auxiliary transmission 11, the second auxiliary transmission 12, and the rear wheel differential device 13. The power branched from immediately before the rear wheel differential device 13 is transmitted to the transmission shaft 15,
Hydraulic clutch type front wheel transmission 16, front wheel transmission shaft 17
And transmitted to the left and right front wheels 19 via the front wheel differential device 18.

The forward clutch 5 and the reverse clutch 6 are hydraulic multi-plate type in which a friction plate (not shown) and a piston (not shown) are combined, and are operated toward the transmission side by supplying hydraulic oil to the spring ( It is urged to the transmission cutoff side by not shown). When the forward clutch 5 is operated to the transmission side, the power of the engine 1 directly flows from the forward clutch 5 to the cylindrical shaft 7 and the vehicle body moves forward. When the reverse clutch 6 is operated to the transmission side, the power of the engine 1 causes the reverse clutch 6 and the transmission shaft 2 to move.
It is transmitted to the cylindrical shaft 7 in the reverse direction via 0, and the machine body moves backward.

The main transmission 10 comprises four hydraulic multi-plate type first speed clutches 21, second speed clutches 22 and third speed clutches 23.
And a four-speed clutch 24 are arranged in parallel in a hydraulic clutch type so that four speeds can be obtained. By operating one of the first-fourth clutches 21-24 to the transmission side, The power from the cylindrical shaft 7 on the first side is subjected to a speed change operation in four stages and transmitted to the transmission shaft 25 on the lower side.

The first auxiliary transmission 11 is also of a hydraulic clutch type in which two hydraulic multi-plate type low speed clutches 26 and a high speed clutch 27 are arranged in parallel, and one of the low speed and high speed clutches 26, 27 is arranged. By operating to the transmission side, the power from the transmission shaft 25 on the main transmission device 10 side is shifted in two stages and transmitted to the second auxiliary transmission device 12 on the lower side. The second sub-transmission device 12 is of a synchromesh type in which the shift member 53 is slid and operated, and is capable of shifting in two stages, and is mechanically shifted by a shift lever 28 described later.

(2) Next, the forward and reverse clutches 5, 6,
The hydraulic circuit for the main transmission 10 and the like will be described. Figure 3
As shown in FIG. 5, an electromagnetic proportional valve 35 (corresponding to a linkage mechanism) for the forward and reverse clutches 5, 6 and a pilot operated switching valve 36a, 37a are provided in an oil passage 30 from the pump 29.
(Corresponding to a linkage mechanism), a pilot operated switching valve 31 for the first to fourth speed clutches 21 to 24 of the main transmission 10.
a, 32a, 33a, 34a, the solenoid proportional valve 3 for the low speed and high speed clutches 26, 27 of the first auxiliary transmission device 11.
8, 39 are connected in parallel.

An oil passage 40 branched from the oil passage 30 is provided with an oil pressure clutch 4 for a diff lock operation in the front wheel diff device 18.
1, a pilot operated switching valve 42a, a hydraulic clutch 43 for differential lock operation in the rear wheel differential device 13
To the pilot operated switching valve 44a, the standard clutch 45 and the speed increasing clutch 46 of the front wheel transmission 16 (see FIG. 1).
(See the reference), pilot operated switching valves 47a, 48
a is connected in parallel. Each switching valve 31a-34
a, 36a, 37a, 42a, 44a, 47a, 48a
Is urged by a spring toward the oil discharge side (transmission cutoff side), and is operated to the supply side (transmission side) by supplying pilot hydraulic oil as described later.

A pilot oil passage 50 is branched from the oil passage 30 via a pressure reducing valve 49, and the pilot oil passage 50 is connected to the switching valves 31a to 34a, 36a, 37a, 42a, 44a.
47a and 48a are connected to the operation parts, and the electromagnetic operation valves 31b, 32b, 33b, 34b and 36b are connected to the operation parts.
(Corresponding to linkage mechanism), 37b (corresponding to linkage mechanism), 42
b, 44b, 47b and 48b are connected. Each solenoid operated valve 31b-34b, 36b, 37b, 42b, 44
b, 47b, 48b are urged toward the oil discharge side (transmission cutoff side) by springs, and when these are electrically operated to the supply side, the pilot operating oil causes the switching valves 31a to 34a, 36b.
a, 37a, 42a, 44a, 47a, 48a are supplied to the operation parts, and these are operated on the supply side (transmission side).

(3) Next, the forward and reverse clutches 5,
6. The configuration of the operation unit of the main transmission 10 and the like will be described. As shown in FIGS. 2 and 3, at the base of the steering handle 58 for the front wheels 19, a forward / backward lever 59 for transmitting an electric forward signal and a backward signal is provided, and the forward / backward lever 59 is provided around the horizontal axis of the control portion of the aircraft. A gear shift lever 28 is supported so as to be swingable. Shift member 5 of second auxiliary transmission device 12 (see FIG. 1)
A shift fork 54 that slides 3 is mechanically interlocked with a shift lever 28 by a linkage mechanism 55, and the shift lever 28 is operated to three positions of a neutral stop position N, a low speed position L, and a high speed position H. The second auxiliary transmission device 12 is operated to change gears. A pair of limit switches 9 for detecting that the speed change lever 28 is operated to the low speed position L and the high speed position H is provided.

A lock pin 56 which is movable up and down is provided on a lateral side portion of the gear shift lever 28, and an operation button 57 for moving the lock pin 56 up and down is provided on an upper portion of the gear shift lever 28. The lock pin 56 is a spring (not shown)
Is urged to move to a fixed position above the paper surface (the operation button 57 is also urged to the protruding side on the left side of the paper surface), and the lock pin 56 is engaged with the fixed guide plate 60. Causes the gear shift lever 28 to move to the neutral stop position N,
It is held at each of the low speed position L and the high speed position H. When the operation button 57 is pushed in, the lock pin 56 is moved to the holding release position below the paper surface, and the gear shift lever 28 can be operated to the neutral stop position N, the low speed position L and the high speed position H.

A shift-up button 61 and a shift-down button 62 are vertically arranged on the left lateral side of the shift lever 28. When the shift-up button 61 and the shift-down button 62 are pushed once as will be described later, one shift operation is performed. Up signal and shift down signal are transmitted,
The shift operation of the main and first auxiliary transmissions 10 and 11 shown in FIG. 1 is performed.

As shown in FIG. 2, a 7-segment shift indicator 64 for displaying the shift positions (1st to 8th gears) of the main and first auxiliary transmissions 10 and 11, and the forward and reverse clutches by the forward / backward lever 59. A forward lamp 65 and a backward lamp 66, which indicate which one of 5 and 6 is operated on the transmission side,
A neutral stop lamp 67 indicating that the shift lever 28 is operated to the neutral stop position N is provided in the control section.
As shown in FIG. 3, a pressure sensor 74 is provided to detect whether or not the operating pressures of the forward and reverse clutches 5 and 6 have reached a predetermined pressure in a transmission state. The lamps 65 and 66 are turned on.

(4) Next, the shift operation by the forward / backward lever 59, the shift lever 28, the shift up button 61 and the shift down button 62 will be described. When the forward / backward lever 59 shown in FIG. 2 is operated to the forward drive position F, an operation current is supplied to the electromagnetic operation valve 36b shown in FIG.
6a is operated to the supply side, the forward clutch 5 is operated to the transmission side, and the forward lamp 65 is turned on. On the contrary, when the forward / reverse lever 59 is operated to the reverse position R, the operation current is supplied to the electromagnetic operation valve 37b shown in FIG. 3, the switching valve 37a is operated to the supply side, and the reverse clutch 6 is moved to the transmission side. When it is operated, the reverse lamp 66 is turned on, and the buzzer 71 (corresponding to notification means) shown in FIG. 2 is intermittently operated.

As shown in FIG. 1, the main transmission 10 is capable of shifting in four stages and the first sub-transmission 11 is capable of shifting in two stages. Gear shifting is possible. In this case, the first auxiliary transmission 1
In the state in which the first low speed clutch 26 is operated to the transmission side, the first to fourth speed clutches 21 to 24 of the main transmission device 10 correspond to the shift positions of the first to fourth speeds, and the first auxiliary transmission device. In the state where the high speed clutch 27 of No. 11 is operated to the transmission side, the first speed to fourth speed clutches 21 to 2 of the main transmission 10 are
4 corresponds to the shift positions of the 5th speed to the 8th speed.

As shown in FIG.
Each of the fourth speed clutches 21 to 24 and the low speed and high speed clutches 26 and 27 of the first auxiliary transmission 11 is provided with a pressure sensor 74 for detecting whether or not the operating pressures thereof have reached a predetermined pressure in a transmission state. The current shift positions (1st speed to 8th speed) of the main and first auxiliary transmissions 10 and 11 are detected by the detection of each pressure sensor 74, and the detected shift positions are displayed on the shift display portion 64. .

When the shift-up button 61 of the shift lever 28 is pushed once while the shift lever 28 shown in FIG. 2 is being operated to the low speed position L or the high speed position H,
The main and first auxiliary transmissions 10, 11 are shifted to a shift position one speed higher than the current shift position, the shift position after the shift is displayed on the shift display portion 64, and the buzzer 71 is operated only once. The operator is informed of the end of the gear shift operation by operating. On the contrary, when the shift down button 62 is pushed once, the main and first auxiliary transmissions 10 and 11 are shifted to a shift position one speed lower than the current shift position, and the shift position after the shift is changed. Displayed on the display unit 64, the buzzer 71 operates only once to notify the operator of the end of the gear shift operation.

Next, for example, the forward / reverse lever 59 is operated to the forward position F (the forward clutch 5 is operated to the transmission side and the reverse clutch 6 is operated to the transmission interruption side), and the speed change lever 28 is moved to the low speed position. In the state of operating to L (the state in which the speed change lever 28 is held at the low speed position L by the operation button 57 and the lock pin 56), the operation button 5
When 7 is pushed and the lock pin 56 is removed downward from the guide plate 60, the switching valve 36a is operated toward the oil drain side by the electromagnetic operation valve 36b shown in FIG.
Is automatically operated to the transmission blocking side.

As a result, the speed change lever 28 is operated from the low speed position L to the neutral stop position N or the high speed position H while the operation button 57 is being pressed, the operation button 57 is returned and the lock pin 56 is used to operate the speed change lever 28. Is held at the neutral stop position N or the high speed position H. In this case, when the operation button 57 is returned to the neutral stop position N, the switching valve 36a is operated to the supply side by the electromagnetic operation valve 36b,
The forward clutch 5 is immediately and automatically operated to the transmission cutoff side by the electromagnetic proportional valve 35. When the operation button 57 is returned to the high speed position H, the switching valve 36a is operated to the supply side by the electromagnetic operation valve 36b, and the forward clutch 5 is gradually and automatically operated to the transmission interruption side by the electromagnetic proportional valve 35. . When the forward / reverse lever 59 is operated to the reverse position R (the reverse clutch 6 is operated to the transmission side and the forward clutch 5 is operated to the transmission interruption side), the operation button 57 of the speed change lever 28 as described above. When is pressed and returned, the reverse clutch 6 is automatically operated to the transmission interruption side and the transmission side.

(5) Next, the operation of the forward and reverse clutches 5, 6 by the clutch pedal 52 and the operation to the transmission interruption side will be described with reference to FIGS. 5 and 6. As shown in FIGS. 2 and 3, a clutch pedal 52 (corresponding to an artificial operation tool) for operating the forward and reverse clutches 5 and 6 is provided, and a potentiometer 68 for detecting the operation position of the clutch pedal 52 (determination means). Equivalent) is provided.
An opening / closing valve 51 (biased toward the closing side by a spring (not shown)) capable of draining pilot working oil from the operating portions of the switching valves 36a and 37a is provided, and the clutch pedal 52 is stepped slightly before the limit. When operated, the clutch pedal 52 mechanically operates the opening / closing valve 51 to the open side, and the switching valve 36
a and 37a are operated to the oil drain side.

As a result, when the clutch pedal 52 is depressed in the range of the depressed position from the return position to the limit, the potentiometer 68 detects the operated position of the clutch pedal 52 (step S1), and FIG.
3, the solenoid proportional valve 35 shown in FIG. 3 is adjusted so that the operating pressure corresponds to the operating position of the clutch pedal 52.
Thus, the operating pressure P of the forward clutch 5 (or the reverse clutch 6) is set (step S2). Clutch pedal 52
Is operated to the intermediate position, the forward clutch 5 (or the reverse clutch 6) can be put in a half-clutch state. When the clutch pedal 52 is operated to the front of the limit step position, the on-off valve 51 is mechanically operated. Then, the switching valves 36a and 37a are switched to the oil drain side so that the operating pressure P of the forward clutch 5 (or the reverse clutch 6) becomes zero.

As shown in FIG. 1, a rotation speed sensor 72 for detecting the input rotation speed W1 (the rotation speed of the engine 1) to the forward and reverse clutches 5 and 6, and an output rotation from the forward and reverse clutches 5 and 6. A rotation speed sensor 73 for detecting the number W2 (the rotation speed of the cylindrical shaft 7) is provided. Next, when the forward clutch 5 (or the reverse clutch 6) is in the half-clutch state by stepping the clutch pedal 52 to the intermediate position (step S3), the pressure sensor 74 shown in FIG. 6) The operating pressure P and the rotation speed sensors 72 and 73 detect the input rotation speed W1 and the output rotation speed W2 (steps S4, S5, and S5).
S6). As a result, the unit absorbed energy EA and the unit absorption efficiency EAT are calculated by the following mathematical formulas (step S7).

[0030]

[Formula 1] F = P · AP−FS P: Operating pressure of forward clutch 5 (reverse clutch 6) AP: Area of piston of forward clutch 5 (reverse clutch 6) FS: Transmission of forward clutch 5 (reverse clutch 6) Energizing force of spring urging to the shut-off side TC = C1, C2, F, RM, Z C1: Mechanical efficiency C2: Dynamic friction coefficient of friction plate of forward clutch 5 (reverse clutch 6) RM: Forward clutch 5 (reverse clutch 6 effective diameter Z of the friction plate): forward clutch 5 (surface number _{^{E = ∫ T 0 TC · (}} W1-W2 of the friction plate of the reverse clutch 6)) dt W1: input rPM W2: output speed T: the clutch pedal Time after depressing 52 to an intermediate position EA = E / (AC · Z · 10 ⁴ ) AC: Area of friction plate of forward clutch 5 (reverse clutch 6) EAT = EA / T

As described above, the unit absorbed energy E
When A and the unit absorption efficiency EAT are calculated, the absorbed energy E1 becomes the unit absorption energy EA and the unit absorption efficiency E.
It is calculated as the product of AT (step S8), the calculated absorbed energy E1 is compared with the set value E2 (step S9), and if the absorbed energy E1 does not reach the set value E2, the process returns to step S1. The absorbed energy E1 is integrated and increases over time as long as the clutch pedal 52 is kept in the intermediate position. Therefore, if the clutch pedal 52 is kept in the intermediate position for a set time, the absorbed energy E1 Eventually reaches the set value E2.

Next, when the absorbed energy E1 reaches the set value E2 while continuing to hold the clutch pedal 52 at the intermediate position, it is determined that the forward clutch 5 (or the reverse clutch 6) is seized, and the electromagnetic operation shown in FIG. The forward clutch 5 (or the reverse clutch 6) is automatically operated by the valves 36b and 37b to the transmission interruption side and held (step S10).
(Corresponding to restraint means). In this case, the buzzer 71 is actuated in a simple manner (the operation interval is shorter than that in the state where the forward / reverse lever 59 is operated to the reverse position R) (step S11),
The worker recognizes that the forward clutch 5 (or the reverse clutch 6) has been automatically operated and held on the transmission cutoff side.

On the contrary, before the absorbed energy E1 reaches the set value E2, the clutch pedal 52 is returned to operate the forward clutch 5 (or the reverse clutch 6) to the transmission cutoff side, or the clutch pedal 52 is set to the stepped position. When the forward clutch 5 (or the reverse clutch 6) is operated to the transmission side by stepping up to (step S3), the accumulated energy E1 accumulated is cleared (step S20), and the process returns to step S1.

(6) Next, the return to the original state after the forward clutch 6 (or the reverse clutch 6) is automatically operated to the transmission interruption side as described in (5) above will be described. In the state where the forward clutch 5 (or the reverse clutch 6) is automatically operated and held on the transmission cutoff side,
As described in the previous section (4), the second lever is set by the speed change lever
In order to perform a shift operation of the auxiliary transmission device 12, the shift lever 2
8 operation button 57 is pressed (step S1
2) When the forward / reverse lever 59 is operated from the forward drive position F to the reverse drive position R (from the reverse drive position R to the forward drive position F) (step S13), the buzzer 71 stops (step S18),
The state in which the forward clutch 5 (or the reverse clutch 6) is held on the transmission interruption side is released (step S19).

Next, when the forward clutch 5 (or the reverse clutch 6) is automatically operated to the transmission interruption side and held, the clutch pedal 52 is depressed to the step position (step S14). When the shift lever 28 of the second auxiliary transmission device 12 shown in FIG. 2 is operated to the high speed position H or the neutral stop position N (step S15), the buzzer 71 is stopped similarly to the above (step S18), and the forward clutch The state in which 5 (or the reverse clutch 6) is held on the transmission cutoff side is released (step S19). Then, returning to step S1, the forward clutch 5 (or the reverse clutch 6) is held on the transmission cutoff side by steps S1 and S2 by stepping the clutch pedal 52 to the stepped position.

When the clutch pedal 52 is stepped to the stepped position while the forward clutch 5 (or the reverse clutch 6) is automatically operated and held at the transmission cutoff side (step S14), FIG. Second auxiliary transmission 1 shown
When the second speed change lever 28 is operated to the low speed position L (step S15), the low speed and high speed clutches 26 and 27 of the first auxiliary transmission device 11 shown in FIG. 1 are automatically operated to the transmission interruption side (step S15). S16), after the first speed and fourth speed clutches 21 and 24 of the main transmission 10 are operated to the transmission side (step S17), the buzzer 71 is stopped (step S18) as described above, and the forward clutch 5 (or The state in which the reverse clutch 6) is held on the transmission cutoff side is released (step S19).

As described above, the process returns to step S1 and the clutch pedal 52 is depressed to the stepped position, so that the forward clutch 5 (or the reverse clutch 6) is held on the transmission cutoff side in steps S1 and S2. Is
Due to the entrainment phenomenon in the forward clutch 5, the power of the engine 1 is transmitted to the lower side via the forward clutch 5 and the vehicle body tries to move forward. Set the second auxiliary transmission 12 to the low speed position L.
When the gear shift operation is performed, since the low rotation and high torque power is transmitted, the above-described phenomenon is particularly remarkable.

As a result, the first speed and the fourth speed of the main transmission 10 are set.
By operating the high speed clutches 21 and 24 to the transmission side, the main transmission 10 is set to the double transmission state in which the transmission ratios of the first speed and fourth speed clutches 21 and 24 are different, and the main transmission 10 stops the power to move the vehicle forward. Suppress. Then, the first auxiliary transmission 1
By operating the low speed and high speed clutches 26 and 27 of No. 1 to the transmission cutoff side, the clutch pedal 52 is stepped to the stepped position to move the forward clutch 5 (or the reverse clutch 6).
Shows the same state as is operated to the transmission cutoff side. In the above-mentioned state, the clutch pedal 52 is returned, the shift lever 28 is operated to the neutral stop position N or the high speed position H, and the forward / reverse lever 59 is moved from the forward drive position F to the reverse drive position R (from the reverse drive position R to the forward drive position F). ) Is released by operating.

[Other Embodiments] In step S10 shown in FIG. 5, when the forward clutch 5 (or the reverse clutch 6) is automatically operated to the transmission shut-off side, instead of the solenoid operated valves 36b and 37b shown in FIG. A dedicated on-off valve (not shown) may be provided, and the on-off valve may be configured to automatically operate the forward clutch 5 (or the reverse clutch 6) to the transmission cutoff side. When the dry transmission clutch (not shown) and the clutch pedal 52 are mechanically linked by a linking rod (corresponding to a linking mechanism) (not shown), an actuator (corresponding to a restraining means) (not shown) Thus, the present invention may be configured such that the clutch pedal 52 is forcibly returned.

Instead of the buzzer 71 shown in FIG. 2, a warning lamp (not shown) may be used as a notification means, and the warning lamp may be made to blink in step S11 shown in FIG. Both the buzzer 71 and a warning lamp (not shown) may be provided, and in step S11 shown in FIG. 5, the buzzer 17 may be operated briefly and at the same time, the warning lamp may blink.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a transmission system in a mission case.

FIG. 2 is a diagram showing a linked state of a shift lever and a second auxiliary transmission device, a shift display portion, and a linked state of each portion.

FIG. 3 is a hydraulic circuit diagram of a main transmission, a first sub transmission, and the like.

FIG. 4 is a diagram showing a relationship between an operating position of a clutch pedal and an operating pressure of a forward clutch (reverse clutch).

FIG. 5 is a diagram showing a first half of a control flow associated with a depression operation of a clutch pedal.

FIG. 6 is a diagram showing the latter half of the flow of control associated with the depression operation of the clutch pedal.

[Explanation of symbols]

5,6 Transmission clutch 35, 36a, 36b, 37a, 37b Linkage mechanism 52 Artificial manipulator 68 discrimination means 71 Notification means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuichi Kitao               64, Ishizukitamachi, Sakai City, Osaka Prefecture               Bota Sakai Factory                (56) Reference JP-A-4-231728 (JP, A)                 JP-A-61-157443 (JP, A)                 JP-A-57-163731 (JP, A)                 Japanese Patent Laid-Open No. 1-115747 (JP, A)

Claims (2)

(57) [Claims] 1. A friction type forward / reverse switching clutch (5),
(6) and an artificial operation tool (52) that is operated by hand, and a linkage mechanism (35), (which links the forward / reverse switching clutches (5), (6) and the artificial operation tool (52). 36
a), (36b), (37a), (37b),
In the state corresponding to the operation position of the artificial operation tool (52),
The forward-reverse switching clutch (5), as well as configured (6) is operated, the forward-reverse switching clutch (5), (6) determining means for detecting whether or not the half-clutch state (68 ) And this half
The forward / reverse switching clutch (5) in the clutch state,
Pressure sensor (74) for detecting the working pressure (P) of (6)
And the half-clutch state of the forward / reverse switching clutches (5) and (6) is based on the detection of the determination means (68).
Set according to the operating pressure (P) detected by the sensor (74)
Operation of the friction type transmission clutch provided with a restraining means for forcibly operating the forward / reverse switching clutches (5) and (6) to the transmission interruption side when continuously maintained for the set time. Construction. 2. The forward / reverse switching clutch by the restraint means
When the switches (5) and (6) are operated to the transmission cut-off side, the forward / reverse switching clutches (5) and (6) are operated by the check means.
A notification means (7
The operation structure of the friction type transmission clutch according to claim 1, further comprising 1).