JP2013024306A - Travelling transmission device of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travelling transmission device of a working vehicle, which does not cause shift shock in a transmission operation by a shift indicator and enables a quick and smooth speed change in response to the transmission operation.SOLUTION: The travelling transmission device of a working vehicle includes a multiple stage transmission system and a transmission control section for performing transmission control of the transmission system in response to the operation of a sequential shift indicator, in which the transmission system includes a switching clutch type high and low speed transmission mechanism 11, a synchronizing switching type main transmission mechanism 12, and a switching clutch type forward/reverse switching mechanism 13. When the shift indicator is operated to a predetermined intermediate shift position by the transmission control section, it is determined whether switching is in the course of operation or switching operation is completed, and switching is sequentially performed to the shift stage of the intermediate shift position which is determined that switching is in the course of operation. Subsequent to the completion of the switching, switching is performed to the shift stage of the shift position which is determined that switching operation is completed.

Description

  The present invention relates to a travel transmission device for a work vehicle that performs multi-stage travel shift control.

  A multi-speed shift type traveling transmission device for a work vehicle disclosed in Patent Document 1 includes a high-speed transmission mechanism, a forward / reverse switching mechanism, and a main transmission mechanism for multi-speed shifting that form a shift transmission system that shifts engine power to traveling wheels. In addition, by providing a shift control unit and operating a sequential shift indicator such as a shift lever, the vehicle speed can be adjusted according to the work.

JP 2004-251351 A

However, the travel transmission device switches the transmission system to the gear position corresponding to the instruction position when the transmission operation by the transmission instruction tool is completed. Since the original traveling vehicle speed is maintained and the operation position is switched to the gear position at the end of the operation, there is a problem that a traveling shock due to a sudden shift is caused.
On the other hand, when the shift control is configured to sequentially switch the gear stage at a constant switching time for shock relaxation, it takes a long time to complete the shift when greatly changing the vehicle speed. There was a problem that a sense of incongruity was inevitable with respect to the speed change operation of the traveling machine body with respect to the operation of the speed change indicator.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a travel transmission device for a work vehicle that does not cause a shift shock when performing a shift operation with a shift instruction tool, and enables a speedy and comfortable shift corresponding to the shift operation. is there.

  The invention according to claim 1 is a transmission transmission system that receives engine output and performs multi-stage transmission to the traveling wheels (2, 3), and a transmission control unit that performs transmission control of the transmission transmission system according to an operation signal of the traveling operation tool. (C), and the shift transmission system includes a high and low speed transmission mechanism (11) that transmits high and low speeds to two speeds by a switching clutch, a main transmission mechanism (12) that transmits multiple speeds, and a switching clutch. A work vehicle comprising a forward / reverse switching mechanism (13) that performs switching transmission, and including a clutch pedal (21), a sequential shift instruction tool (22), and a forward / reverse switching tool (23) as the travel operation tool. In the travel transmission device, when the gear shift indicator (22) is operated to a predetermined intermediate gear shift position by the gear shift control unit (C), the operation classification between the middle of the operation of the gear shift indicator (22) and the end of the operation is set. According to the prescribed criteria Determination Te, and sequentially switches the shift speed of the intermediate gear position is determined as the middle operation, and switches to the speed of the determined shift position and the operation completion Following completion of the switching.

  The shift control unit switches a shift transmission system composed of a high / low speed shift mechanism, a main shift mechanism, and a forward / reverse switching mechanism to multiple shift stages for forward / reverse according to the shift position of the shift indicator. In the operation state of the pointing tool, the operation classification between the operation end and the operation end is discriminated, and the operation gear is sequentially switched to a gear position at a predetermined intermediate shift position during the operation, and then switched to the gear position based on the operation end determination.

According to a second aspect of the present invention, in the configuration of the first aspect, the operation classification is determined by an operation speed of the shift instruction tool (22).
The operation status is determined based on the operation speed of the shift instruction tool.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the high / low speed transmission mechanism (11) is configured in parallel in two systems to receive the engine output together, and the main transmission mechanism (12). Is configured in two systems and receives the output of the high and low speed transmission mechanism (11) for each system, all the gear stages are configured with different gear ratios, and gear stages with adjacent gear ratio orders are configured in other systems, The forward / reverse switching mechanism (13) is arranged in series in common on both output sides to form a transmission system, and a neutral shift position at the low speed end of the shift stage operation range of the shift indicator (22). (N) is provided, and the high and low speed transmission mechanism (11) and the forward / reverse switching mechanism (13) are both cut off from transmission by the neutral shift position (N), and both systems of the main transmission mechanism (12) are connected to each other. To control the transmission to the lower gear And butterflies.
The main transmission mechanism is configured such that transmission can be interrupted on the upstream and downstream sides of each of the two systems by a clutch of the transmission mechanism, and transmission and transmission on the upstream and downstream sides of the main transmission mechanism are respectively determined by the neutral position of the transmission provided on the transmission indicator. At the same time, it is controlled to the transmission state.

According to a fourth aspect of the present invention, in the configuration of the third aspect, the shift control unit (C) includes both the high / low speed shift mechanism (11) and the forward / reverse switching mechanism (13) based on the neutral instruction of the shift transmission system. The transmission control is neutral, and the transmission of both systems of the main transmission mechanism (12) is controlled to a predetermined shift stage.
Due to the double meshing of the main transmission mechanism and the transmission interruption on the upstream and downstream sides thereof, the transmission to the traveling wheels by the driving power is interrupted.

  According to the first aspect of the present invention, the shift control unit has a multi-stage shift transmission system including a high / low speed transmission mechanism, a main transmission mechanism, and a forward / reverse switching mechanism for forward / reverse movement according to the shift position of the shift indicator. Switch to the gear position. Also, determine the operation classification between the operation end and the operation end for the operation status of the shift indicator, and switch to the gear position at the predetermined intermediate shift position during the operation. Switch. Therefore, by selecting a part of the multiple shift speeds and setting the intermediate shift speed, even when the gear shift indicator is operated greatly, the shift speed switching is started as soon as the operation is started. Even when the pointing tool is operated rapidly, a smooth shift without shifting shock is possible through sequential switching up to the gear position at the end of the operation.

  According to the second aspect of the present invention, in addition to the effect of the first aspect, the operation status can be determined based on the operation speed of the speed change instruction tool. When the speed is changed and the operation is continued at a low speed, the speed is changed by one step, and the control operation is performed in accordance with the operation. Therefore, the operator can operate without a sense of incongruity.

  According to the invention of claim 3, in addition to the effect of claim 1 or claim 2, the main transmission mechanism is configured such that transmission can be cut off by the clutch of the transmission mechanism on the upstream and downstream sides of each of the two systems. Since the transmission upstream and downstream sides of the main transmission mechanism are respectively cut off and controlled to the transmission transmission state by the neutral position of the transmission provided on the transmission instruction tool, when the transmission operation by the transmission instruction tool is started, the transmission on the upstream / downstream side is controlled. Since the transmission can be performed together with the transmission operation of the clutch of the mechanism, the responsiveness of the transmission operation can be improved.

  According to the invention according to claim 4, in addition to the effect of claim 3, the double meshing of the main transmission mechanism and the transmission interruption on the upstream and downstream sides thereof interrupt the transmission to the traveling wheel by the follow-up power, thereby stabilizing the body. Can be secured.

Overall side view of tractor Transmission system development diagram of traveling transmission Transmission configuration list for each gear stage of the transmission system System block diagram of shift control Sketch of the lever guide for the main gearshift lever Transmission configuration list for shifting control during stop (a) and start operation (b) Timing chart when starting with forward / reverse lever operation Timing chart when starting with clutch pedal operation Transmission configuration list 1 for shifting control during traveling Transmission configuration list 2 for shifting control during traveling Timing chart of shifting operation example 1 during traveling Timing chart of shifting operation example 2 while traveling Timing chart of shifting operation example 3 while traveling Hydraulic control of clutch according to shift pattern (a) to (e)

Embodiments specifically configured based on the above technical idea will be described below with reference to the drawings.
FIG. 1 is an overall side view of a tractor shown as an example of a work vehicle to which the present invention is applied. This work vehicle 1 supports the machine body by front and rear traveling wheels 2 and 3 so as to be able to work on the field, and has a shift transmission system that receives the power of the engine 4 at the front of the machine body and performs transmission transmission to the traveling wheels 2 and 3. A transmission which is the traveling transmission device 5 is provided. The traveling transmission device 5 is also provided with a work machine transmission system that is transmitted to the work power supply unit 6, which is abbreviated as PTO, and is capable of driving a work machine W such as a rotary mounted on the rear hitch.

  As shown in the development diagram of the transmission system in FIG. 2, the traveling transmission device 5 includes two high- and low-speed transmission mechanisms 11 and 11 that transmit two high- and low-speed transmission elements by two clutches using respective clutches, and a multi-speed transmission. Two main transmission mechanisms 12 and 12 that transmit multi-stage transmission by power synchro shift, forward / reverse switching mechanism 13 that transmits forward and reverse transmission elements by respective clutches, and multi-speed transmission by gear shift And a sub-transmission mechanism 14 connected in series to provide a transmission gear transmission system for shifting the engine power so as to be capable of multi-stage shifting, and a PTO transmission gear transmission 15 is provided as a work machine transmission system, and the working clutch The work input shaft 15a, which is an input shaft, receives engine power together with the high and low speed transmission mechanisms 11, 11, and is transmitted to the work power supply unit 6 via the PTO shaft 15b.

  The high and low speed transmission mechanisms 11 and 11 are arranged in parallel in two systems to transmit high and low outputs from the engine output shaft 4a to the high and low speed shafts 11b and 11b via the common input shaft 11a, respectively, and the main transmission mechanisms 12 and 12 Are configured separately on the output side of the high and low speed transmission mechanisms 11 and 11, respectively, and transmit transmission power in common to the main transmission shaft 12b, and the four-speed sub-shift from the forward / reverse shaft 13b of the forward / reverse switching mechanism 13 arranged in series. It is transmitted to the front and rear wheels 2 and 3 via the mechanism 14.

  The main transmission mechanisms 12 and 12 are sandwiched between the clutch type high / low speed transmission mechanisms 11 and 11 and the forward / reverse switching mechanism 13 on both the upstream and downstream sides of the two systems. The clutch of the engine 4 can cut off the rotation transmission from both the engine 4 and the traveling wheels 2 and 3, and since it does not receive the rotation difference between the engine rotation and the vehicle speed, the gear change can be quickly performed by a small-capacity synchro mechanism. . Therefore, the traveling transmission device 5 can reduce the total length of the transmission by reducing the size of the main transmission mechanisms 12 and 12 while ensuring the shift changeability during traveling. It can contribute to the improvement of the turning ability.

  Since the forward / reverse switching mechanism 13 can be made compact by configuring the forward gear and the reverse gear to be switched by a clutch, the required forward / backward length dimension can be increased as compared with the case where a gear shift type forward / backward switching mechanism is provided before or after the clutch. It can be configured by shortening.

  The switching drive of the high and low speed transmission mechanisms 11, 11 operates the clutch by the switching valve, and the switching driving of the forward / reverse switching mechanism 13 is configured to be able to control the power transmission by the proportional pressure control valve, thereby performing the pressure control. In addition, stabilization corresponding to variations in the characteristics of the clutch, the valve, and the drive circuit of the control unit can be achieved. In other words, by controlling the clutch pressure on the side that is always connected while the clutch is being driven at the time of shifting, individual proportional valve control is not required, and variation in shifting characteristics between products is minimized and stable at low cost. The system can be configured.

  Further, the work input shaft 15a is provided with the PTO transmission transmission unit 15 for receiving power from the engine together with the high and low speed transmission mechanisms 11 and 11 to control the work machine power, so that the high and low speed transmission mechanisms 11 and 11 and the work input shaft 15a are provided. Since the engine power is always supplied, the traveling speed change transmission device 5 that supplies the engine power to the traveling system and the working system can be configured with a minimum transmission configuration.

  The two high and low gear stages of the high and low speed transmission mechanisms 11 and 11 are configured in common with each other, and all the two gear stages of the main transmission mechanisms 12 and 12 are configured with different gear ratios. Are arranged in separate systems. Specifically, with respect to the main transmission mechanisms 12 and 12 in the figure, the speed ratio rank is one of the two systems, and the first and third speed reduction gear trains according to the first and third speed ratios, and the other is the second and second speed reduction gear trains. All the 4th speed gears are configured to be switchable between the 2nd speed and 4th speed reduction gear trains according to the fourth gear ratio.

  The specific transmission configuration of the above-described transmission transmission system is as follows. One of the high and low speed transmission mechanisms 11 and 11 for switching between the low speed L and the high speed H is the same as that of the main transmission mechanism 12 and 12, as shown in the shift stage list in FIG. Four shift stages of 1L, 1H, 3L and 3H can be selected by switching between 1st and 3rd speeds, and 4L can be selected as 2L, 2H, 4L and 4H by switching between the 2nd and 4th speeds. Forward F and Reverse R With the combination of the forward / reverse switching mechanism 13 for switching the forward / reverse travel, it is possible to perform 8-speed multi-speed shifting for forward / reverse travel. Further, by switching the discontinuous shift stages for each system of the main transmission mechanisms 12 and 12, it is possible to drive both systems at the same time. Smooth transmission can be achieved by interrupting transmission.

  The travel transmission device 5 having the above-described configuration includes an operation tool for travel control including a shift and a control unit C for shift control, and configures the travel transmission device. As the operation tool, a clutch pedal 21 for stepping operation is sequentially provided. 4 is provided with a main transmission lever 22 which is a type of shift instruction tool, and a forward / reverse lever 23 for forward / reverse selection. As shown in the system block diagram of FIG. 4, operation sensors 21s for each operation tool and motion sensors 12s for each device. , And the rotation sensors 4r, 13r, etc., are input to the control unit C to constitute a shift control system capable of controlling the drive units 11d of the transmission devices.

  The clutch pedal 21 inputs a depression amount signal from the clutch pedal sensor 21 s to the control unit C, and controls transmission cut-off control of the high / low speed transmission mechanisms 11, 11 and the forward / reverse switching mechanism 13 neutrally according to the depression operation, Further, as shown in the sketch of the lever guide in FIG. 5, the main transmission lever 22 is provided with a gear position from positions 1 to 8, a neutral N position and an automatic transmission AT position for accelerator transmission, and at the neutral N position. The transmission of the high and low speed transmission mechanisms 11 and 11 and the forward / reverse switching mechanism 13 are both neutral, and both the main transmission mechanisms 12 and 12 are switched to one of the gear stages to perform transmission control, so that the engine side and the traveling wheel can be controlled. On either side, power transmission due to the clutch is prevented, and the main transmission mechanisms 12 and 12 that have already been shifted are used to Since the power transmission is started in response to returning operation of the pedal 21, without by synchro operation characteristics of the main transmission mechanism 12, 12 can be ensured response.

  The main transmission mechanisms 12 and 12 are configured to hold the shift in the non-transmission-side system in a completed state, and are held at different shift positions according to instructions from the main transmission lever 22. For example, when the instruction of the main transmission lever 22 is position 2, the high / low speed transmission mechanism 11 of the 1st to 3rd system is shifted to the high speed H side, and the 1st to 3rd main transmission mechanism 12 is controlled to the 1st speed. The transmission control of the forward / reverse switching mechanism 13 is controlled, and at this time, the other 2nd to 4th speed systems are maintained by shifting the high / low speed transmission mechanism 11 to the neutral and the main transmission mechanism 12 to the second speed. When shifting by lever operation, the main transmission mechanism 12 has already been shifted, so in many cases there is no need to switch in conjunction with the shifting operation. Time can be reduced to a minimum.

  The relationship between the shift instruction position of the main transmission lever 22 and the shift positions of the main transmission mechanisms 12 and 12 is controlled at least as follows. That is, when the indicated position of the main shift lever 22 is 1st to 3rd speed, the shift speeds of both systems are 1st speed and 2nd speed, and when the instruction is 6th to 8th speed, the gear speed is 3rd speed and 4th speed. In the case of 4th and 5th gears, shifting to any one of the shift speeds simplifies the algorithm of the shift control processing, and the shift operation of the synchro shift type shift unit linked to the shift operation can be reduced.

  The detailed control at the time of shifting is such that the clutch transmission is controlled so that power can be transmitted after the shifting of the main transmission mechanisms 12 and 12 is completed, and the high and low speed shifting mechanisms 11 and 11 reach the meet position of the clutch after shifting. By taking into account the piston movement time and controlling the clutch to be held in the transmission state at the position before the shift, the power interruption can be minimized.

  Further, the forward / reverse switching mechanism 13 is driven to the pressure reducing side almost simultaneously with the neutral operation of the high / low speed transmission mechanisms 11 and 11 before shifting, and the pressure reducing side is synchronized with the estimated meet timing of the clutch of the high and low speed shifting mechanisms 11 and 11 after shifting. By gradually driving to the side where the connection torque is gradually increased (step-up), there is less power interruption at the time of shifting, and control can be performed without double meshing, so that the feeling of shifting can be improved.

  When the shift instruction change width is a plurality of stages or more, the shift method is changed according to the change amount of the shift position by the main shift lever 22 so as to shift to the final shift target position through the shift to the intermediate shift stage. For example, when the vehicle speed difference such as 1st to 8th is large, if the gear is shifted all at once, the acceleration corresponding to the vehicle speed difference is generated and the shift shock becomes large. By changing the speed by inserting an intermediate speed position with a gear position in between, the speed change shock can be reduced by a speed change with a reduced vehicle speed difference.

  The shift position of the main shift lever 22 is detected by an analog amount such as a potentiometer, and the shift instruction position is determined within a range of a step width in which the detected step amount is substantially constant. It is possible to easily determine the shift instruction position. In addition, it can be determined whether the operation is continued or completed by setting the detected value as an analog amount, for example, whether it is the second speed position in the process of shifting from the first speed to the fourth speed, or from the first speed to the second speed. It is possible to determine whether the speed is the second speed upon completion of the operation.

  In this case, the shift control can be stabilized by a measure such as providing hysteresis in the shift instruction position range with respect to the operation direction. For example, it is possible to prevent chattering detection of detection at a switching position where the detection of the first speed and the second speed is repeatedly changed.

(Intermediate shift speed control)
Next, the shift control by the intermediate shift stage will be described.
According to the control processing of the shift control unit C, the operation classification between the operation in progress and the operation end of the shift instruction tool 22 is determined based on a predetermined reference, and if the determination is in the middle of the operation, a predetermined intermediate gear selected from all the gears Are sequentially switched to the intermediate speed stage that has passed, and then the speed is changed to the speed stage based on the determination of the end of the operation following the end of the intermediate speed stage.

  By configuring the speed change control in this way, the speed change transmission system including the high / low speed speed change mechanism 11, the main speed change mechanism 12, and the forward / reverse switching mechanism 13 is moved forward and backward by the speed change control unit C according to the operation of the speed change indicator 22. It is possible to switch to multiple gears, and the operation status of the gear change indicator is determined during operation and when the operation is completed. Switched. Therefore, by selecting a part of the multiple shift speeds and setting the intermediate shift speed, even when the gear shift indicator is operated greatly, the shift speed switching is started as soon as the operation is started. Even when the pointing tool is operated rapidly, a smooth shift can be performed without a shift shock by sequentially switching the intermediate shift stage until the shift stage at the end of the operation.

  The operation classification of the middle of the operation of the shift instruction tool 22 and the operation end of the operation can determine the operation status based on the operation speed of the shift instruction tool, and when the shift instruction tool is operated at once by this determination classification, In addition, if the operation is continued at a low speed, the gears are shifted one step at a time, and each is controlled according to the operation, so that the operator can operate without a sense of incongruity. .

(Lever neutral control)
When the gear change indicator 22 is operated to the neutral N position, the high and low speed transmission mechanisms 11 and 11 and the forward / reverse switching mechanism 13 are both clutched off to cut off transmission, and both the main transmission mechanisms 12 and 12 are connected. By performing transmission control to the respective low-speed gears, the transmission mechanism on both the upstream and downstream sides is not required without requiring the main transmission mechanisms 12 and 12 to be synchronized when the shift operation by the shift indicator 22 is started next time. Since the transmission of the clutches 11 and 13 can be performed together with the transmission operation of the clutches 13 and 13, the response of the transmission operation can be improved.

(Transmission neutral control)
The neutralization control of the transmission system excluding the neutral operation of the auxiliary transmission 14 controls the transmission of the high and low speed transmission mechanisms 11 and 11 and the forward / reverse switching mechanism 13 to be neutral and controls both the main transmission mechanisms 12 and 12 to a predetermined level. By performing transmission control to the shift stage, the double-geared main transmission mechanisms 12 and 12 are in the transmission cut-off state on both the upstream and downstream sides thereof, so that the transmission to the traveling wheels by the follow-up power is cut off and the body is stabilized. Can be secured.

(Example of shift control)
Next, a specific example of the shift control operation will be described.
First, as shown in the transmission configuration list of FIG. 6A, the transmission transmission control of the transmission transmission system when the vehicle is stopped is performed by turning off the two high-speed transmission mechanisms 11 and 11 and the forward / reverse switching mechanism 13. For the two systems of the main transmission mechanisms 12 and 12, transmission control is performed to a position corresponding to the position of the main transmission lever 22.

  For example, when the vehicle is stopped by operating the forward / reverse lever 23 to the neutral N position, if the main transmission lever 22 is in the first speed position, only the two main transmission mechanisms 12, 12 are started up for preparation. To control transmission to 1st speed on and 2nd speed on. When the clutch pedal 21 is operated to the depressed position and the vehicle is stopped, if only the main transmission lever 22 is in the first speed position, similarly, only the two main transmission mechanisms 12, 12 are started up for preparation. To control transmission to 1st speed on and 2nd speed on.

  Further, the transmission transmission control of the transmission transmission system at the time of the start operation corresponds to the operation of the high / low speed transmission mechanism 11 corresponding to the operation of the forward / reverse lever 23 or the clutch pedal 21 as shown in the transmission configuration list of FIG. While transmission control of the forward / reverse switching mechanism 13 is performed by a clutch, the transmission state of the two main transmission mechanisms 12 and 12 is maintained.

  As for the details of the shift control at the time of starting, as shown in the timing chart of FIG. 7, the case of starting by the forward / reverse lever 23 is returned and released, the main transmission lever 22 is set to the first speed position, and the forward / backward movement is performed. When the lever is stopped at the neutral position, if the forward / reverse lever 23 is operated to the forward position, the Hi-Lo clutch (1-3) is controlled from OFF to L (1), and at the same time, the forward / reverse switching mechanism. 13 clutches are connected from off to forward with a predetermined hydraulic curve, and during this time, the Hi-Lo clutch (2-4) is turned off, the main transmission (1-3) is turned on at the first speed, and the main transmission (2- 4) In preparation, maintain the transmission state with the second speed on. In this case, the clutch piston starts the connection operation after the respective movement times t1 and t2.

  As described above, when the vehicle is started by operating the forward / reverse lever 23 from the neutral position to the forward position, the main transmission mechanism 12 of the transmission system corresponding to the position of the main transmission lever 22 is left as it is, and the high / low speed transmission mechanism 11 and forward / reverse switching are performed. While the clutch on the corresponding side of the mechanism 13 is boosted to transmit power, the high / low speed transmission mechanism 11 of the standby system remains neutral and maintains the transmission state of the main transmission mechanism 12 for preparation.

  As shown in the timing chart of FIG. 8, when the clutch pedal 21 is started, the forward / reverse lever 23 is set to the neutral position, the main transmission lever 22 is set to the first speed position, and the clutch pedal 21 is depressed to stop the vehicle. When the clutch pedal 21 is returned, the Hi-Lo clutch (1-3) is controlled from OFF to L (1), and at the same time, the clutch of the forward / reverse switching mechanism 13 is changed from OFF to forward. The hydraulic curve is increased according to the pressure and connected. During this time, the Hi-Lo clutch (2-4) is turned off, the main transmission (1-3) is turned on at the first speed, and the main transmission (2-4) is prepared. Transmission control is performed with the second speed on. In this case, the clutch piston starts the connection operation after the respective movement times t1 and t2.

  As described above, when starting by returning the clutch pedal 21, the transmission side high / low speed transmission mechanism 11 and the forward / reverse switching mechanism 13 corresponding to the position of the main transmission lever 22 are boosted to start power transmission. On the other hand, the transmission state of the main transmission mechanism 12 is maintained for preparation while the high-low speed transmission mechanism 11 of the standby system remains neutral.

  Next, regarding the transmission transmission control during travel, the transmission configuration list 1 in FIG. 9 and the transmission configuration list 2 in FIG. 10 are respectively shown when the main transmission lever 22 is in the position of the fourth speed or less and in the position of the fifth speed or more. As shown in the drawing, when the speed change operation width is large as the main speed change lever 22 is operated, the two speed main transmission mechanisms 12 and 12 are moved to positions corresponding to the positions of the main speed change lever 22 through the intermediate speed stage in parentheses. Perform transmission control.

  This shift transmission control will be described in detail. As shown in the timing chart of the shifting operation example 1 during traveling in FIG. 11, the clutch pedal 21 is released, the forward / reverse lever 23 is moved forward, and the main shift lever 22 is moved forward at position 1. When operated to position 2 during traveling, the Hi-Lo clutch (1-3) is switched from L (1) on to H (3) on, and the forward / reverse clutch is moved forward and once at L (1) off timing. While the pressure is reduced to a low pressure that does not transmit power and the pressure is gradually increased, the Hi-Lo clutch (2-4) is turned off and the main transmission mechanism 12 (1-3) is used with the first speed on and the main speed change. (2-4) starts up to prepare for turning on the second gear. In this case, the lever operation time t3 includes an operation completion determination time t4 based on the moving speed, and the clutch of the high / low speed transmission mechanism 11 starts to be connected after the lever operation time t3 and the clutch piston moving time t1, and the fixed time t5 The forward / reverse clutch is turned off forward (approximately 10 milliseconds before) to prevent double biting.

  Thus, when the main speed change lever 22 is operated to position 2 during forward traveling at position 1, the transmission element of the high / low speed transmission mechanism 11 of the transmission side system is switched from low speed to high speed, The forward / reverse switching mechanism 13 is temporarily depressurized and connected in transmission by increasing a predetermined hydraulic curve.

  12, the clutch pedal 21 is released, the forward / reverse lever 23 is moved forward, and the main shift lever 22 is moved to position 5 while moving forward at position 1 as shown in the timing chart of shifting operation example 2 during traveling. In this case, the Hi-Lo clutch (1-3) is switched from L (1) on to off and L (1) is turned on again, and the Hi-Lo clutch (2-4) is switched from off to L (2) on. Turn off again, the main transmission clutch (1-3) is turned off from the use of the 1st speed and is used at the 3rd speed on, the main transmission clutch (2-4) is started up with the 2nd speed on and ready to start The clutch keeps moving forward and depressurizes and gradually increases each time the Hi-Lo clutch is switched. In this case, the lever operation time t3 is a time point determined by the shift operation to the position 3 or higher, the shift transmission control of the position 3 is started from that time point, and the switching of the main shift is performed for a predetermined neutral holding time. t6 is secured.

  As described above, when the main transmission lever 22 is operated to the position 5 while the vehicle is traveling forward at the position 1, the transmission control is performed with the intermediate speed control of the position 3 interposed therebetween, and the high / low speed transmission mechanism 11 Each time switching is performed, the forward / reverse switching mechanism 13 is temporarily depressurized to increase the pressure with a predetermined hydraulic curve.

  In addition, as shown in the timing chart of the shifting operation example 3 in FIG. 13, when the main transmission lever 22 is operated to the position 7 while traveling forward at the position 2, the position 4 is changed depending on the shift position and the vehicle rolling condition. For an example in which 5 is an intermediate shift stage, a shifting operation to position 4 or higher starts a shift operation to 4th speed without completing shifting, and a shift to 5th speed is performed by 7th speed finalizing operation. And the main shift (2-4) is switched in advance following the end of the shift.

Next, clutch hydraulic pressure control for transmission switching at the time of shifting will be described.
Regarding the hydraulic control of the clutch, as shown in FIG. 14, the shift example (a) from position 1 to 2 is a shift without power interruption and only the clutch switching of the high / low speed transmission mechanism 11, and double engagement. In addition, control is performed so as not to cover when the oil temperature is low. The shift pattern position shift corresponds to 1 → 2, 2 → 1, 3 → 4, 4 → 3, 5 → 6, 6 → 5, 7 → 8, and 8 → 7.

  Further, the example of shifting from position 1 to 5 (b) is a shifting (not used) in which the power is cut off when shifting at a stroke, and only the main transmission mechanism 12 is switched. Such shift of the shift pattern position corresponds to 1 → 5, 5 → 1, 2 → 6, 6 → 2, 3 → 7, 7 → 3, 4 → 8, and 8 → 4.

  Further, the shift example (c) from position 2 to 3 is a shift without power interruption, in the case of clutch switching of the high / low speed transmission mechanism 11 and system switching of the main transmission mechanisms 12 and 12, where the oil temperature is low. Is controlled so as not to wear. The shift of the shift pattern position is 1 → 4, 7, 8, 2 → 3,4, 7, 8, 3 → 1, 2, 5, 6, 4 → 1, 2, 5, 6, 5 → 3, 4, 7, 8, 6 → 3, 4, 7, 8, 7 → 1, 2, 5, 6, 8 → 1, 2, 5, 6

  In addition, the shift example (d) from position 1 to position 6 is a shift (not used) in which the power is cut off when the shift is performed at once, and is a case where the main transmission mechanism 12 and the high / low speed transmission mechanism 11 are switched. Such shifts and shifts in pattern position correspond to 1 → 6, 2 → 5, 3 → 8, 4 → 7, 6 → 1, 5 → 2, 8 → 3, 7 → 4. In this case, when shifting the same main transmission mechanism 12, a waiting time of about 100 milliseconds is secured after the neutral holding.

  An example of shifting from position 4 to position (e) is a shift without power interruption, and is a shift that requires switching of the synchro-type main transmission when shifting, and the clutch piston of the high / low speed transmission mechanism 11 When the initial time (meet time) is shorter than the main shift switching time, the passage of the time is set as the shift destination entering timing. In other words, the high / low switching shift is performed after a sufficient time has elapsed for the main shift switching.

(Operation check)
Next, the operation confirmation control of the transmission device will be described.
As a control for confirming the operation of the transmission device, when the sub-transmission mechanism 14 is in a neutral state, a transmission system comprising a high / low-speed transmission mechanism 11, a main transmission mechanism 12, and a forward / reverse switching mechanism 13 on the upstream side is used. By performing control so as to have a shift behavior linked to the shift operation, it is possible to check the behavior of each clutch-type or synchro-shift type shift mechanism in the travel stop state in a device operation check or the like during maintenance.

  In addition, an adjustment mode for measuring the piston of the clutch is provided for clutch adjustment, a rotation sensor is provided downstream from each clutch output shaft, and the piston stroke is measured by a change in rotation when each clutch is driven in the adjustment mode. With this configuration, it is possible to reduce the power interruption at the time of shifting, and to reliably detect the stroke up to the meet point by the rotation sensor.

In this case, the flow rate change error due to the pressure loss corresponding to the oil viscosity can be prevented by controlling the control that the oil temperature T of the hydraulic oil is equal to or higher than the specified temperature as the measurement condition of the piston stroke.
The rotation sensor detects the pressure of each clutch chamber by changing the driving order of each clutch by one sensor 13r provided downstream of the forward / reverse shaft 13b, which is the output shaft of the forward / reverse switching mechanism 13. A reliable meet point can be detected and a cost reduction can be achieved without the need for a sensor for individually detecting the.
In addition, the rotation sensor is installed in a portion where the rotation speed change due to the gear switching of the auxiliary transmission mechanism 14 does not occur, so that the auxiliary transmission mechanism 14 can be neutralized and adjustment work can be performed in a stopped state. It can be carried out even in a narrow place where it cannot be taken.

  Piston stroke is measured by driving the drive valve at an opening at which the maximum flow rate is reached, and measuring the time equivalent to the piston stroke of the clutch (the time during which the clutch piston moves from the initial position to the meet point using the specified drive method). Stable measurement is possible.

  Also, the time corresponding to the piston stroke is calculated from the engine speed being measured at the detection position (rotation sensor position) at the time of measurement of the corresponding clutch from the engine speed being measured. Is determined by the time until the point at which the value becomes equal to or greater than the specified ratio, and is used for each clutch control as the piston stroke reference time. As described above, when the measurement is performed in the check mode, the detection is performed by comparing the engine rotation speed being measured with the rotation speed calculated by the reduction ratio, so that correct detection can be performed even when the engine rotation is roughly adjusted.

  The measured piston stroke reference data of the high / low speed transmission mechanism 11 is calculated and used based on the shift destination piston stroke reference data as data for determining the timing of turning off the shift source clutch immediately before the shift destination clutch meets. By configuring the transmission source clutch to be turned off in a little less time with respect to the piston stroke reference data, it is possible to drive so as not to cause double engagement and improve the durability of the clutch.

  The measured piston stroke reference data of the forward / reverse switching mechanism 13 is used to quickly perform the time until the clutch meet of the forward clutch or the reverse clutch when the power transmission is started by the forward / reverse operation or the clutch piston operation, and the initial pressure at the clutch meet. Is used as the initial large current (large flow rate) drive time for the proportional control valve to control with the appropriate one according to the conditions such as the running shift position, and the valve and valve drive circuit against the piston stroke reference data during measurement It is used for the control data in a slightly short time considering the response delay. In this way, in order to stably output the initial pressure at the time of meeting, the clutch is used for control with a slightly shorter initial time so that the drive pressure does not increase due to the responsiveness of the valve. Control becomes possible.

  Further, since the main transmission mechanisms 12, 12 (main 1-3, main 2-6) are located between the clutches to be measured, at least the clutch of the forward / reverse switching mechanism 13 during the clutch piston stroke measurement in the adjustment mode. The control process is configured so that the shift state is maintained for a while after one measurement is completed during the measurement.

  For example, when the forward clutch measurement is completed and the reverse clutch measurement is performed, the clutch case is configured to be integrated forward and backward, so if the rotation stop after measurement is slow, the start of the next measurement is delayed and the piston stroke measurement is delayed. It will take a long time in total. In the present plan, for example, by turning off the clutch output after measuring the forward clutch, the brake can be braked by the main transmission switching mechanism 12 to stop the rotation of the clutch case early, and the total time of the adjustment mode can be shortened. it can.

  The measurement is performed multiple times for each clutch, and the reference data is determined from all the results. In addition, it is necessary to wait for the clutch piston to return to the initial position before driving, so it is the same. When measuring the clutch continuously several times, it takes a long time for the adjustment mode, so the order of measurement avoids continuous measurement of the same clutch, for example, alternately forward clutch and reverse clutch, etc. At least, the total time can be shortened by performing the sequential operation with different clutches interposed therebetween.

(Transmission start operation)
In the transmission start operation, when the main speed change lever 22 is operated when the clutch pedal 21 is depressed, it is possible to determine whether the operation of the main speed change lever 22 or the end of the operation can be determined as described above. In this case, only the main shift switching mechanism 12 is shifted when passing through the intermediate shift position, and only the main shift switching mechanism 12 is operated when the operation is completed. As described above, the main transmission mechanisms 12 and 12 are configured to move to the necessary positions in the same manner as when the main transmission lever 22 is operated, so that the operation of gradually returning the clutch pedal 21 is started immediately. Can respond.

  Even when the main speed change lever 22 is operated in the neutral position with other speed change operation tools, it is possible to determine whether or not the main speed change lever 22 is being operated or has ended, as in the case where the clutch pedal 21 is depressed. In the middle of the operation, only the main shift switching mechanism 12 is shifted when passing the intermediate shift position, and at the end of the operation, only the main transmission mechanism 12 is operated based on the end of the operation. It is possible to move with good responsiveness at the start of shifting operation such as.

DESCRIPTION OF SYMBOLS 1 Work vehicle 2 Traveling wheel 3 Traveling wheel 4 Engine 4a Engine output shaft 5 Traveling transmission (traveling transmission device)
6 Working power supply unit 11 High and low speed transmission mechanism (clutch)
11a Common input shaft 12 Main transmission mechanism 13 Forward / reverse switching mechanism (clutch)
14 Sub-transmission mechanism 15 PTO transmission transmission unit 15a Work input shaft 21 Clutch pedal 22 Main transmission lever (shifting indicator)
23 Forward / reverse lever N Neutral shift position W Working machine t1 Piston movement time t2 Piston movement time t3 Lever operation time t4 Operation completion judgment time t5 Fixed time t6 Neutral holding time

Claims (4)

A transmission transmission system that receives engine output and performs multi-stage transmission to the traveling wheels (2, 3), and a transmission control unit (C) that performs transmission control of the transmission transmission system according to an operation signal of the traveling operation tool, The transmission transmission system includes a high / low speed transmission mechanism (11) that transmits high and low speeds through a switching clutch, a main transmission mechanism (12) that transmits multiple speeds, and a forward / reverse switching mechanism (forward / reverse switching transmission using a switching clutch). 13), and as the travel operation tool, a travel transmission device for a work vehicle comprising a clutch pedal (21), a sequential shift instruction tool (22), and a forward / reverse switching tool (23).
When the shift control unit (C) is operated to a predetermined intermediate shift position by the shift control unit (C), the operation classification between the middle of the operation of the shift instruction tool (22) and the end of the operation is determined based on a predetermined reference. A traveling transmission device for a work vehicle, wherein the vehicle is sequentially switched to a gear position at an intermediate shift position determined to be in the middle of operation, and is switched to a gear position at a shift position determined to be completed after completion of the switching.   The traveling transmission device for a work vehicle according to claim 1, wherein the operation classification is determined by an operation speed of the shift instruction tool (22).   The high / low speed transmission mechanism (11) is configured in parallel in two systems to receive engine output, and the main transmission mechanism (12) is configured in two systems to output the output of the high / low speed transmission mechanism (11). In addition to receiving the gears separately, all the gears have different gear ratios, and gears having adjacent gear ratios are arranged in another system, and the forward / reverse switching mechanism (13) is shared in series on both output sides. And a neutral transmission position (N) is provided at the low speed end of the gear stage operating range of the transmission indicator (22), and the high and low speed transmission is performed by the neutral transmission position (N). The transmission of both the mechanism (11) and the forward / reverse switching mechanism (13) is cut off, and the transmission of both systems of the main transmission mechanism (12) is controlled to the respective low-speed gears. The work vehicle according to claim 2. Line transmission.   The shift control unit (C) neutrally controls both the high / low speed shift mechanism (11) and the forward / reverse switching mechanism (13) based on the neutral instruction of the shift transmission system, and controls both of the main transmission mechanism (12). 4. The traveling transmission device for a work vehicle according to claim 3, wherein transmission control of the system is performed to a predetermined gear position.

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