JPH0565759U - Work vehicle drive transmission structure - Google Patents

Abstract

(57) [Abstract] [Purpose] It is configured to transmit driving power from a continuously variable transmission to a pair of left and right traveling devices via a pair of left and right side clutches, and to supply and discharge hydraulic oil from a pump. Drive a work vehicle equipped with a hydraulic actuator that cuts off transmission of one of the selected side clutches, and a hydraulic side brake that brakes one travel device by supplying and discharging hydraulic oil from the pump. In the power transmission structure, a structure is simply configured to surely stop the machine body when the shift lever is operated to the neutral stop position. [Configuration] When the neutral sensor 44 detects that the shift lever 43 for the continuously variable transmission 1 has been operated to the neutral stop position N, the left and right traveling devices are braked,
It is provided with hydraulic operating means 5 and 6 for operating the side brake 28 with hydraulic oil from the pump 32.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a traveling power transmission structure for a work vehicle configured to transmit traveling power from an engine to a pair of left and right traveling devices from a continuously variable transmission through a pair of hydraulic left and right side clutches, or The present invention relates to a traveling power transmission structure of a work vehicle including a hydraulic side brake that brakes a traveling device on a transmission interruption side, in addition to the continuously variable transmission and the side clutch.

[0002]

[Prior Art]

 Examples of the continuously variable transmission used for traveling in the work vehicle as described above include a hydrostatic continuously variable transmission type, a belt type with a split pulley, and a taper cone type. Such a continuously variable transmission is capable of smoothly shifting gears from the neutral stop position where power is not transmitted to the highest speed position.By operating this continuously variable transmission to the neutral stop position, the aircraft is stopped. Can be made

[0003]

[Problems to be solved by the device]

 As described above, the aircraft can be stopped by operating the continuously variable transmission to the neutral stop position.However, the range of the neutral stop position where power is not transmitted is extremely high in this continuously variable transmission. Narrow. Therefore, even if the operator tries to stop the machine by operating the gear shifting operation tool for the continuously variable transmission (such as the gear shift lever or the speed change pedal) to the neutral stop position, the continuously variable transmission may be slightly moved from the neutral stop position. It may be in a detached state. As a result, power may flow from the continuously variable transmission and the aircraft may move. INDUSTRIAL APPLICABILITY The present invention makes effective use of the hydraulic circuit structure in a traveling transmission structure of a work vehicle equipped with a hydraulic side clutch, or a hydraulic side clutch and a side brake, and operates the gear shift operation device to a neutral stop position. The purpose is to make sure that the aircraft will stop if it does.

[0004]

[1]

 The power for traveling is configured to be transmitted from the continuously variable transmission to the pair of left and right traveling devices via the pair of left and right side clutches, and one of the selected ones is selected by the operation of supplying / discharging the hydraulic oil from the pump. In the travel transmission structure of a work vehicle equipped with a hydraulic actuator that shuts off the transmission of the side clutch and a hydraulic side brake that brakes one traveling device by supplying and discharging hydraulic oil from the pump, To configure. A neutral sensor that detects when the gearshift operating device that artificially shifts the continuously variable transmission is operated to the neutral stop position, and based on the detection of this neutral sensor, the left and right running devices are braked. , A hydraulic operating means for operating the side brake by hydraulic oil from the pump is provided.

[2] The power for traveling is configured to be transmitted from the continuously variable transmission to the pair of left and right traveling devices via the pair of left and right side clutches, and the operation oil is supplied and discharged from the pump. A traveling power transmission structure of a work vehicle including a hydraulic actuator for transmitting and shutting off one of the selected side clutches is configured as follows. The neutral sensor is equipped with a hydraulic brake that can brake the left and right traveling devices, and a neutral sensor that detects when the gear shifting operation device that artificially speeds the continuously variable transmission is operated to the neutral stop position. Based on the detection of, the hydraulic operating means for operating the brake with the hydraulic oil from the pump is provided.

[0006]

[Action]

 [I] With the configuration as described in [1] above, when the operator operates the speed change operation tool to the neutral stop position, the left and right traveling devices are braked by the side brakes, so that the continuously variable transmission device for traveling. Even if the vehicle is slightly out of the neutral stop position, the aircraft will stop reliably due to the braking action of the side brakes. In the work vehicle equipped with side clutches and side brakes as described in [1] above, these are used for turning. In other words, if the hydraulic actuator is used to cut off the transmission of the right side clutch, for example, the right traveling device will rotate freely and the resistance from the ground will cause the aircraft to slowly turn to the right. Then, when the side travel device is braked by the side brake, the aircraft turns to the right. Therefore, if the side brake for turning is used for stopping when the gear shift operation device is operated to the neutral stop position, it is not necessary to provide a dedicated brake for stopping, and the side brake can also be used for stopping. Since a pump that supplies hydraulic oil to the side brakes when turning is used as a hydraulic pressure source that operates the side brakes to the braking side when stopping, it is necessary to provide a dedicated hydraulic pressure source for stopping. Absent.

[II] According to the constitution described in [2], when the operator operates the speed change operation tool to the neutral stop position, braking is applied to the left and right traveling devices from the brake, so that there is no step for traveling. Even if the transmission is slightly out of the neutral stop position, the braking action of the brake ensures that the aircraft will stop properly. In a work vehicle equipped with a side clutch as described in [2] above, this is used for turning. In other words, when the hydraulic actuator operates, for example, the transmission of the right side clutch to shut off the transmission, the right traveling device turns into a free rotation state, and due to the resistance from the ground, the aircraft gently turns to the right. Therefore, since a pump that supplies hydraulic oil to the hydraulic actuator for the side clutch at the time of turning is used for stopping when the gear change operation tool is operated to the neutral stop position, it is not necessary to provide a hydraulic source dedicated to the brake. ..

[0008]

[Effect of the device]

 According to the present invention, when the gear shift operation device is operated to the neutral stop position, the aircraft surely stops. Therefore, the gear operation device is operated to the neutral stop position without unexpected movement of the aircraft. It is possible to improve the safety in the case. Further, since the side brake for turning and the pump thereof are also used for stopping when the speed change operation tool is operated to the neutral stop position, the parts can be made common and the structure can be simplified. According to the present invention, when the gear shift operation device is operated to the neutral stop position, the aircraft surely stops. Therefore, the gear operation device is operated to the neutral stop position without unexpected movement of the aircraft. It is possible to improve the safety in the case. Further, since the pump for the turning side clutch is also used as the hydraulic pressure source for the brake when the gear shift operation device is operated to the neutral stop position, the parts can be shared and the structure can be simplified. it can.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a structure inside a transmission case 8 of a traveling system in a combine, which is an example of a work vehicle, in which a power from an engine (not shown) is provided with a belt transmission mechanism (not shown) equipped with a tension clutch. Power is transmitted to the input pulley 2 of the hydrostatic continuously variable transmission 1 via the output shaft 3 of the continuously variable transmission 1 via the first transmission shaft 4 and a reaper (not shown). ) Is transmitted to.

The power from the first transmission shaft 4 is transmitted to the second transmission shaft 11 via the first gear 9 and the second gear 10. A shift gear 14 is slidably fitted to the second transmission shaft 11 by a spline structure, while a high speed gear 16 and a low speed gear 17 are fixed to a third transmission shaft 15 corresponding thereto. With the above structure, by sliding the shift gear 14 to engage with the high-speed gear 16 or the low-speed gear 17, the power can be shifted to two high and low stages. It is transmitted to the gear 19.

A right side gear 21R and a left side gear 21L are fitted to the support shaft 20 supporting the third gear 19 so as to be rotatable relative to each other, and an input gear 23 of the left and right axles 22 is connected to the left and right side gears 21R, 21L is always occluded. As a result, the right or left side gear 21R, 21L is slid on the third gear 19 so as to be occluded / separated, and power transmission and transmission interruption operations are performed on the left and right crawler type traveling devices 24. Side clutches 25R and 25L are formed between the third gear 19 and the left and right side gears 21R and 21L.

Next, a structure for braking the traveling device 24 on the transmission interruption side for turning will be described. As shown in FIG. 2, the right fourth gear 26R and the left fourth gear 26L are supported by the support shaft 20 so as to be relatively rotatable, and a pair of fifth gears 29 fixed to the fourth transmission shaft 27 are provided. Meshes with the right fourth gear 26R and the left fourth gear 26L. A multi-plate hydraulically operated side brake 28 is provided at one end of the fourth transmission shaft 27. As a result, the right side gear 21R or the left side gear 21L is separated from the third gear 19, is engaged with the right fourth gear 26R or the left fourth gear 26L, and the side brake 28 is turned on to operate one of the two. The traveling device 24 can be braked. And, this is a turning state.

Next, a structure will be described in which one traveling device 24 is normally driven at a lower speed than the other for turning. As shown in FIG. 2, the first sprocket 13 is fixed to the third transmission shaft 15, and the second sprocket 38 is externally fitted to the fourth transmission shaft 27 so as to be rotatable relative to each other. A power transmission chain 40 is wound around. The gently swiveling clutch 12 is provided between the second sprocket 38 and the fourth transmission shaft 27. As a result, when the right or left side gear 21R, 21L is engaged with the right or left fourth gear 26R, 26L, if the slow turning clutch 12 is engaged and operated, the forward rotation power from the third transmission shaft 15 is reduced to 1 /. It is decelerated to 2 and transmitted to one of the running devices 24. And, this is a gentle turning state.

Next, a hydraulic oil supply structure for the hydraulic cylinders 31R, 31L (corresponding to hydraulic actuators) for sliding the left and right side gears 21R, 21L, the side brake 28, and the slow swing clutch 12 will be described. As shown in FIG. 1, the hydraulic oil from the pump 32 is supplied to the hydraulic cylinders 31R, 31L for the left and right side gears 21R, 21L via the first switching valve 33, and at the same time, the hydraulic cylinders 31R, 31L. The oil passage 34 from the side surface is connected to the electromagnetic brake type second switching valve 35 for the side brake 28 and the slow swing clutch 12. Further, a variable relief valve 36 for the side brake 28 and the slow swing clutch 12 is connected to the oil passage 34.

Next, the operation of the first switching valve 33, the second switching valve 35, and the variable relief valve 36 will be described. As shown in FIG. 1, a switching lever 18 for the second switching valve 35 is provided in the longitudinal portion of the machine body. Based on the operating position of this switching lever 18, the controller 7 controls the second switching valve 35 to operate. A switching operation is performed between a gentle turning position 35a for supplying hydraulic oil to the slow turning clutch 12 and a neutral turning position 35b for supplying hydraulic oil to the side brake 28. Further, the operation lever 39 provided in the control section of the machine body, the first switching valve 33 and the variable relief valve 36 are mechanically linked via the first linkage mechanism 41 and the second linkage mechanism 42.

The state shown in FIG. 1 is a state in which the switching lever 18 is operated to the pivot position, and the second switching valve 35 is operated to the pivot position 35b. In this state, when the operating lever 39 is operated from the neutral position N to the first turning position R1 on the right or the first turning position L1 on the left, only the first switching valve 33 is operated and the hydraulic cylinder 31R or 31L is operated. , The right or left side gear 21R, 21L, which is in mesh with the third gear 19 via the right or left operation portion 46R, 46L, is separated from the third gear 19 to the right or left fourth gear 26R, 26L. Bite into.

In this case, since the variable relief valve 36 is in the fully open state and the side brake 28 is in the open state, the transmission to the right or left traveling device 24 is cut off (the side clutch 25R or 25L is not connected). (Transmission cutoff state) and the aircraft slowly turns to the right or left. The sequence valve 47 provided in the oil passage 34 supplies the pressure required for the right or left side gear 21R, 21L to completely mesh with the right or left fourth gear 26R, 26L. , 31L.

Next, when the operating lever 39 is operated from the right or left first turning position R1, L1 to the right or left second turning position R2, L2, the right or left side gears 21R, 21L move to the right. Alternatively, when the left fourth gears 26R and 26L are engaged with each other and the second switching valve 35 is operated to the turning position 35b, the variable relief valve 36 is gradually operated from the fully opened state to the closed side. As a result, the side brake 28 starts to act and the right or left traveling device 24 is gradually braked, and the aircraft makes a right turn or left turn. Then, the braking force of the side brake 28 becomes maximum at the second turning position R2, L2 to the right or left of the operating lever 39.

Next, when the switching lever 18 is operated to the gentle turning position, the second switching valve 35 is switched to the gentle turning position 35a. In this state, when the operating lever 39 is operated from the neutral position N to the first turning position R1, L1 on the right or left, the transmission cutoff state of the right or left side clutch 25R, 25L appears as in the above.

Next, when the operation lever 39 is operated from the right or left first turning position R1, L1 to the right or left second turning position R2, L2, the right or left side gear 21R, 21L is moved to the right. Alternatively, in the state where the left fourth gears 26R and 26L are engaged with each other and the second switching valve 35 is operated to the gentle turning position 35a, the variable relief valve 36 is gradually operated from the fully opened state to the closed side as described above. Go away. As a result, the slow turning clutch 12 starts to act, and the right or left traveling device 24 is gradually driven to rotate in the forward direction at a low speed, so that the aircraft slowly turns right or left. Then, at the right or left second turning position R2, L2 of the operation lever 39, the slow turning speed becomes maximum.

Next, the case where the continuously variable transmission 1 is operated to the neutral stop position will be described. As shown in FIG. 1, an electromagnetically operated valve 5 (corresponding to hydraulic pressure operation means) is provided between the pump 32 and the first switching valve 33. The electromagnetic operation valve 5 supplies the working oil from the pump 32 to the first switching valve 33, and the working oil from the pump 32 to the first switching valve 33 to supply the working oil to the first switching valve 33. It is a two-position switching type in which the oil discharge passage is shut off and the operating oil from the pump 32 is also supplied to the side brakes 28, and it is operated to the work position 5a side by a panel. Then, at the working position 5a, the gentle turning and the turning of turning by the operation lever 39 as described above can be performed. Further, an electromagnetic opening / closing valve 6 (corresponding to hydraulic operating means) is provided between the second switching valve 35 and the side brake 28, and is biased toward the communication side by a spring.

As shown in FIG. 1, the control section of the machine body is provided with a shift lever 43 (corresponding to a shift operation tool) for shifting the continuously variable transmission 1. Is operated from the neutral stop position N to the forward maximum speed position F and the reverse maximum speed position R to perform the shift operation of the continuously variable transmission 1. Further, a contact type neutral sensor 44 for detecting that the shift lever 43 has been operated to the neutral stop position N is provided. As shown in FIG. 3, the lever guide 45 of the shift lever 43 is not linear, but is bent at the neutral stop position N. Further, an adjusting bolt 48 capable of adjusting the left and right range of the neutral stop position N in FIG. 3 is provided on the back side of the lever guide 45.

With the above structure, when the operator operates the speed change lever 43 to the neutral stop position N and the detection signal from the neutral sensor 44 is input to the control device 7, the control device 7 causes the electromagnetically operated valve 5 to operate. Is operated to the stop position 5b, and the electromagnetic on-off valve 6 is operated to the closed position. As a result, the hydraulic oil is supplied to the first switching valve 33 in a state where the drain passage of the first switching valve 33 is blocked, so that the hydraulic oil is supplied to the left and right hydraulic cylinders 31R and 31L and the left and right side gears are supplied. 21R and 21L mesh with the right and left fourth gears 26R and 26L. Then, the hydraulic oil from the pump 32 is supplied to the side brake 28 from the electromagnetically operated valve 5 and the opening / closing valve 50 (a normally closed type that opens when the electromagnetically operated valve 5 side reaches the set pressure). Since the valve 6 is operated to the closed position, the side brake 28 is operated to the braking side, the left and right traveling devices 24 are braked, and the airframe is stopped.

[Other Embodiments] In the above-described embodiment, the switching lever 18 is configured to be able to select between the gentle turning state and the solid turning state. However, the switching lever 18 is used to select the gentle turning state and the super turning state. The present invention may be applied to this structure by being configured so as to be able to select a turning state (turning performed by driving one traveling device 24 in reverse). Next, the above structure will be described. As shown in FIG. 5, the gently swiveling clutch 12 for slowly swiveling is mounted in the mission case 8, and a hydraulic brake 49 is mounted at one end of the fourth transmission shaft 27.

Next, a structure for driving one traveling device 24 in the reverse direction will be described. As shown in FIG. 5, a sixth gear 37 that meshes with the high-speed gear 16 of the third transmission shaft 15 is externally fitted to the fourth transmission shaft 27 so as to be rotatable relative to the sixth gear 37 and the fourth transmission shaft. A hydraulic multi-plate reversing clutch 30 is provided between the reversing clutch 27 and 27. Accordingly, when the right side gear 21R or the left side gear 21L is engaged with the right fourth gear 26R or the left fourth gear 26L and the reverse clutch 30 is operated, the power from the high speed gear 16 is reversed. Moreover, it is decelerated to 1/2 and transmitted to one traveling device 24. And this is the super-confidential turning state.

A hydraulic circuit as shown in FIG. 4 is provided for the mission case 8 of FIG. 5, and when the switching lever 18 is operated to the gentle turning position and the super-position turning position, the control device 7 operates. The second switching valve 35 is operated to the gentle turning position 35a for supplying the working oil to the slowly turning clutch 12 and the supertrust turning position 35c for supplying the working oil to the reverse rotation clutch 30. As a result, when the operation lever 39 is operated from the neutral position N to the right or left first turning position R1, L1 in the state where the switching lever 18 is operated to the gentle turning position, the same operation as described above is performed to the right or left. The transmission cutoff state of the left side clutch 25R, 25L appears. Then, when the right or left second turning position R2, L2 is operated, one of the traveling devices 24 is driven to rotate in the forward direction at a low speed so that a gentle turning can be performed.

Next, when the switching lever 18 is operated to the super-oriented turning position, the second switching valve 35 is switched to the super-oriented turning position 35c. In this state, when the operating lever 39 is operated from the neutral position N 1 to the first turning position R1 or L1 on the right or left, the transmission cut-off state of the right or left side clutch 25R, 25L appears as described above.

Next, when the operating lever 39 is operated from the right or left first turning position R1, L1 to the right or left second turning position R2, L2, the right or left side gears 21R, 21L move to the right. Alternatively, in the state where the left fourth gears 26R and 26L are engaged with each other and the second switching valve 35 is operated to the super-spinning rotation position 35c, the variable relief valve 36 is gradually closed from the fully opened state as described above. Will be operated by. As a result, the reverse rotation clutch 30 starts to operate, and the right or left traveling device 24 is gradually driven in reverse rotation, and the aircraft makes a super turning turn to the right or left. Then, the reverse rotation speed becomes maximum at the right or left second turning position R2, L2 of the operation lever 39.

Next, a case where the continuously variable transmission 1 is operated to the neutral stop position will be described. As shown in FIG. 4, an electromagnetically operated valve 5 (corresponding to hydraulic operating means) is provided between the pump 32 and the first switching valve 33. The electromagnetic operation valve 5 supplies the working oil from the pump 32 to the first switching valve 33, and the working oil from the pump 32 to the first switching valve 33 to supply the working oil to the first switching valve 33. It is of a two-position switching type in which the oil discharge passage is shut off and the working oil from the pump 32 is also supplied to the second switching valve 35, namely, the stop position 5b, and the spring is operated to the working position 5a side.

A brake 49 is connected to an oil passage 51 branched from between the second switching valve 35 and the slow swing clutch 12. The oil passage 51 is provided with a supply position 52a for supplying the brake 49 with hydraulic oil to the slow swing clutch 12 to operate the brake 49, and a brake 49 for discharging hydraulic oil from the brake 49. A solenoid operated valve 52 (corresponding to hydraulic operating means) that can be switched between two positions, an oil drain position 52b for operating the brake release side, is provided. It is biased to the 52b side. An electromagnetic opening / closing valve 56 (corresponding to hydraulic operating means) is provided between the second switching valve 35 and the variable relief valve 36.

With the above-described structure, when the operator operates the speed change lever 43 to the neutral stop position N and the detection signal from the neutral sensor 44 is input to the control device 7, the control device 7 causes the solenoid operated valve 5 to operate. Is operated to the stop position 5b, and the second switching valve 35 is operated to the gentle turning position 35a regardless of the operating position of the switching lever 18. Then, the electromagnetic on-off valve 52 is operated to the supply position 52a, and the electromagnetic on-off valve 56 is operated to the closed position.

As a result, the working oil is supplied to the first switching valve 33 in a state where the oil discharge passage of the first switching valve 33 is blocked, so that the working oil is supplied to the left and right hydraulic cylinders 31R and 31L. The left and right side gears 21R and 21L mesh with the right and left fourth gears 26R and 26L. Then, the hydraulic oil from the pump 32 is supplied to the slow swing clutch 12 and the brake 49 via the electromagnetically operated valve 5, the check valve 53, the oil passage 34 and the second switching valve 35. As a result, the slow swing clutch 12 is operated to the transmission side and the brake 49 is operated to the braking side, the left and right traveling devices 24 are braked, and the machine body is stopped.

The neutral sensor 44 shown in FIGS. 1 and 4 may be replaced with a structure shown in FIG. In other words, in the hydrostatic stepless transmission 1, the gear 54 is fixed to the trunnion shaft 1a for shifting which is operatively connected to the shift lever 43, and the rotary potentiometer 55 (corresponding to the neutral sensor) This is a structure in which a gear 55a fixed to the detection shaft is engaged with the gear 54. As a result, when the output from the potentiometer 55 is within the set range, it is determined that the speed change lever 43 and the trunnion shaft 1a are in the neutral stop position N.

It should be noted that reference numerals are added to the claims of the utility model 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 hydraulic circuit diagram of a side clutch, a hydraulic cylinder, a side brake, etc.

FIG. 2 is a schematic vertical sectional front view showing a transmission structure in a mission case.

FIG. 3 is a plan view of a lever guide of a shift lever.

FIG. 4 is a hydraulic circuit diagram of a side clutch, a hydraulic cylinder, a side brake, and the like in the first alternative embodiment.

FIG. 5 is a schematic vertical sectional front view showing a transmission structure in a mission case in the first alternative embodiment.

FIG. 6 is a side view of the vicinity of a shift lever and a neutral sensor according to a second embodiment.

[Explanation of symbols]

 1 continuously variable transmission 5, 6, 52, 56 hydraulic operating means 24 traveling device 28 side brake 25R, 25L side clutch 31R, 31L hydraulic actuator 32 pump 43 shift operating tool 44, 55 neutral sensor 49 brake N neutral operating gear Stop position

Claims (2)

[Scope of utility model registration request] 1. A structure for transmitting traveling power from a continuously variable transmission (1) to a pair of left and right traveling devices (24) via a pair of left and right side clutches (25R), (25L). , One side clutch (25R) selected by the operation of supplying / discharging the hydraulic oil from the pump (32),
(25L) hydraulic actuator (3
1R), (31L), and traveling of a work vehicle provided with a hydraulic side brake (28) for braking one traveling device (24) by supplying / discharging operation oil from the pump (32). Neutral sensors (44), (55) having a power transmission structure for detecting that a speed change operation tool (43) for artificially speed-changing the continuously variable transmission (1) is operated to a neutral stop position (N). ), And based on the detection of the neutral sensors (44) and (55), the side brake (2) is operated by hydraulic oil from the pump (32) so that the left and right traveling devices (24) are braked.
8) A work vehicle traveling transmission structure including hydraulic operating means (5), (6) for actuating (8). 2. The traveling power is transmitted from the continuously variable transmission (1) to the pair of left and right traveling devices (24) via the pair of left and right side clutches (25R), (25L). , One side clutch (25R) selected by the operation of supplying / discharging the hydraulic oil from the pump (32),
(25L) is a hydraulic drive brake (49) capable of braking the left and right traveling devices (24), which is a traveling power transmission structure of a work vehicle including hydraulic actuators (31R) and (31L) for performing transmission interruption operation. And a neutral sensor (44), (5) for detecting that the gear shift operation tool (43) for artificially shifting the continuously variable transmission (1) is operated to the neutral stop position (N).
5) and hydraulic operating means (5), (52) for operating the brake (49) with hydraulic oil from the pump (32) based on the detection of the neutral sensors (44), (55). , (56), which is a work vehicle traveling transmission structure.