JP2008275043A - Crawler traveling vehicle traveling operation device - Google Patents

Abstract

An object of the present invention is to change a running speed at the time of start or stop by using a forward / reverse clutch that switches the rotation direction of the left and right drive shafts back and forth to switch the traveling direction to forward or reverse, or turns. It is an object to be able to perform smoothly without changing the rotation.
In a crawler traveling vehicle in which a drive system of a crawler traveling device is provided with a forward / reverse clutch D that is operated by hydraulic drive, a traveling sensor S that detects an operation amount of a traveling operation tool E is provided. The traveling operation device of the crawler traveling vehicle is characterized in that the traveling speed is controlled by setting the forward / reverse clutch D to the half clutch state by the output.
[Selection] Figure 14

Description

  The present invention relates to a traveling operation device for changing and controlling a traveling speed in a crawler traveling vehicle using a crawler traveling device such as a tractor or a combine.

  A work vehicle using a crawler traveling device has a turning clutch in which the rotation direction can be reversed near the left and right drive shafts of the crawler traveling device in order to enable a super-revolution to turn by changing the rotation direction of the left and right crawlers. D is provided.

For example, Japanese Patent Laid-Open No. 7-312964 discloses a configuration of a transmission case in which left and right turning clutches D are provided on the lower transmission side of a steering clutch and a steering brake, and Japanese Patent Laid-Open No. 2002-255057 discloses a turning clutch. The structure of a transmission case provided with a sudden turning clutch and a super turning clutch is shown. Although this work vehicle is a combine, a similar transmission case is used also in the tractor, and the turning clutch turns in response to the turning operation of the steering lever or the steering handle while appropriately changing the rotation of the drive shaft. .
Japanese Patent Laid-Open No. 7-312964 JP 2002-255057 A

  The work vehicle is configured to drive various working devices such as a threshing device and a rotary as the aircraft runs with a single engine. During the work, the working device is driven with a constant work rotation. In order to change the traveling speed, it is necessary to change the speed while cutting off the power transmission to the traveling device. In order to make the shifting of the traveling device smooth, a continuously variable transmission may be incorporated in the drive system of the traveling device, but the manufacturing cost becomes expensive.

  Therefore, the present invention uses a forward / reverse clutch that switches the rotation direction of the left and right drive shafts back and forth to switch the traveling direction to forward or reverse, or turns, and changes the traveling speed at the start or stop. It is an object to be able to perform smoothly without changing.

The problems of the present invention are solved by the following technical means.
The invention described in claim 1 is a crawler traveling vehicle provided with a forward / reverse clutch D that is operated by hydraulic drive in the drive system of the crawler traveling device 13, and is provided with a traveling sensor S that detects an operation amount of the traveling operation tool E, The traveling operation device of the crawler traveling vehicle is characterized in that the traveling speed is controlled by setting the forward / reverse clutch D to the half clutch state based on the output of the traveling sensor S.

  With this configuration, the amount of operation of the travel operation tool E is adjusted so that the forward / reverse clutch D provided in the power transmission portion to the crawler travel device 13 is in a half-clutch state, and the power transmission is adjusted without changing the engine rotation. You can change the running speed.

  According to the second aspect of the present invention, the travel operation tool E is the clutch operation tool 26 for operating the main clutch 52, and the clutch engagement state of the forward / reverse clutch D is set to the half clutch state by the clutch engagement operation of the clutch operation tool 26 A traveling operation device for a crawler traveling vehicle characterized by the fact

  In this configuration, when the clutch operating tool 26 is turned on at the start of traveling, the main clutch 52 is turned on after the half-clutch state of the forward / reverse clutch D in the drive system of the crawler traveling device 13 and the traveling is started slowly. To do.

  The invention according to claim 3 is a brake operation tool 25 in which the travel operation tool E decelerates the traveling speed, and the main clutch while the forward / reverse clutch D is brought into a half-clutch state as the brake operation tool 25 is braked. The traveling operation device of the crawler traveling vehicle is characterized in that the brake braking state is set by cutting off 52.

  With this configuration, when the brake operating tool 25 is braked, the forward / reverse clutch D of the drive system of the crawler travel device 13 passes the half-clutch state, and the main clutch 52 is disengaged to apply the brake, thereby reducing the engine rotation. Slowly stop driving without letting go.

  According to the first aspect of the present invention, the smooth start / stop operation for slowly changing the traveling speed of the crawler traveling device 13 while keeping the forward / reverse clutch D in the half-clutch state without affecting the rotation of the engine. It is possible to reduce the manufacturing cost.

According to the second aspect of the present invention, it is possible to perform a smooth start without a shock of power connection by simply turning on the clutch operating tool 26 without changing the engine rotation.
According to the first aspect of the present invention, when the brake operating tool 25 is braked, the power transmission from the drive system of the crawler traveling device 13 to the traveling device can be cut off and braking can be performed without affecting the rotation of the engine. Does not affect the processing power of the relationship.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall view of a crawler tractor T to which a transmission case of the present invention is applied.

  As shown in FIG. 1, the tractor T has an engine mounting frame 10 at the front of the vehicle body, an engine 11 attached to the frame 10, and an engine output shaft (not shown) protruding from the rear of the engine 11. In this configuration, the coaxial rotation is transmitted to the transmission in the casting trans-transmission case 12 arranged in the longitudinal direction of the vehicle body. Further, the rotational power appropriately decelerated by the transmission is transmitted to the left and right crawler type traveling devices 13 via bevel gears 56 and 85 described later, a sprocket shaft 86 in the left and right axle case, and the like.

  Above the trans-transmission case 12, a floor 14 is supported, and on this floor 14, a steering handle 15 serving as a steering operation section and a forward / reverse switching lever 24 for switching the traveling to the left and right of the steering handle 15 to forward and backward. And a finger lever 23 (see FIG. 2) for raising and lowering a ground work machine such as a rotary R or a front dozer (not shown) mounted on the front side of the machine body, and a cockpit 18 on the rear side of the steering handle 15 are provided. Sits down and performs maneuvering.

  Provided on the left side of the cockpit 18 are a main transmission lever 9 for shifting the traveling speed in four steps, a position lever 16 for adjusting the height of the work implement, and an auxiliary transmission lever 17 for shifting the traveling speed in two steps of high and low, A backup switch 19, a tilt adjustment dial 20 that adjusts the tilt of the rotary R, a manual adjustment lever 21, and a horizontal control changeover switch 22 are provided on the right side of the cockpit 18, and a brake corresponding to the brake operation tool of the present invention is provided on the floor 14 at the foot. The pedal 25 and the clutch pedal 26 corresponding to the clutch operating tool of the present invention are provided. The brake pedal 25 and the clutch pedal 26 are collectively referred to as a travel operation tool E.

  The front dozer may be moved up and down by the position lever 16 instead of the finger lever 23. At this time, the position lever 16 is preferably urged so as to return to the neutral position.

  Fenders 27 that cover the top of the crawler traveling device 13 are provided on the left and right sides of the floor 14. The left and right fenders 27 are configured to be attached with a detachable fuel tank 28. The upper shape of the fuel tank 28 is formed along the fender 27, and a handle 29 extending in the front-rear direction is provided on the upper surface. It has become. This handle 29 becomes a hand catcher for getting on and off as it is.

  On the upper surface of the transmission case 12, a lifting hydraulic cylinder 30 serving as a working machine lifting actuator is provided, and a lift arm 31 connected to a piston of the cylinder 30 is turned up and down to thereby operate the working machine via a link mechanism. It is the structure which raises / lowers.

  Also, a part of the link mechanism at the rear of the vehicle body is provided with a left and right horizontal cylinder 32 as a left and right rolling actuator of a work machine, and the operation amount is detected by a stroke sensor (not shown) provided in the cylinder 32. It has become.

  As shown in FIGS. 3 and 4, the front panel 33 provided at the lower front side of the steering handle 15 includes a fuel gauge 34, a battery charge warning light 35, an engine oil pressure warning light 36, a water temperature warning light 37, and a system abnormality warning light 38. , A spin turn indicator lamp 39, a mild turn indicator lamp 40, an hour meter 41 for indicating work time, a main shift position indicator lamp 42, and a horn switch 44, a blinker lever on the lower left side of the front panel 33. 43, a light switching lever 45, and a turning mode switching switch 46 are provided.

Next, the power transmission structure in the transmission case 12 of the tractor T will be described mainly with reference to FIGS.
As shown in FIG. 9, the transmission case 12 has a configuration in which five hollow cases of a front case 99, a first intermediate case 100, a second intermediate case 101, a third intermediate case 102, and a rear case 103 are connected.

  Rotational power input from the output shaft of the engine 11 to the input shaft 50 protruding from the front case 99 is first pivotally supported on the first intermediate case 100 of the transmission case 12 by a reduction gear set 51 provided on the input shaft 50. It is transmitted to the main clutch input shaft 54 and drives the main clutch 52. The power that is turned on and off by the main clutch 52 is appropriately decelerated by the main transmission A and the sub-transmission B provided in the third intermediate case 102 of the transmission case 12 and pivotally supported by the rear case 103. It is transmitted to an output shaft 55 having a bevel gear 56. A hydraulic pump 57 is mounted on the outer side of the front case 99 of the main clutch input shaft 54 and driven.

The main clutch 52 engages / disengages power to the main clutch output shaft 53 and is turned on / off by a clutch petal 26 on the floor 14.
The main transmission A includes a main drive shaft 58 provided on an extension line of the main clutch output shaft 53, and a first driven shaft 59 and a second driven shaft 60 that are vertically arranged around the main drive shaft 58. Has been.

  The rotational power of the main clutch output shaft 53 is transmitted to a reduction shaft 63 having a large diameter gear 62 that meshes with a gear 61 provided at the rear end of the main clutch output shaft 53, and meshes with the small diameter gear 64 of the reduction shaft 63. Is transmitted from the gear 65 to the main drive shaft 58.

  A gear 66 that is spline-engaged with the main drive shaft 58 and a gear 67 that is bearing on the second driven shaft 60 via a needle bearing are always meshed with each other, and is spline-engaged with the main drive shaft 58. A small-diameter gear 68 and a gear 69 that is supported by the first driven shaft 59 via a needle bearing are always meshed with each other. The gear 65 and the gear 66 are an integral gear.

  Further, a gear 70 that is spline-engaged with the main drive shaft 58 and a gear 71 that is supported by a first driven shaft 59 via a needle bearing are in constant mesh. Further, the gear 72 that is spline-engaged with the main drive shaft 58 and the gear 73 that is supported by the second driven shaft 60 via a needle bearing are always meshed with each other.

The first driven shaft 59 is provided with a cylinder case 74 in which a first-speed clutch C1 and a third-speed clutch C3 are housed so as not to be relatively rotatable.
The first intermediate shaft 101 side of the first driven shaft 59, the second driven shaft 60, and the main drive shaft 58 is pivotally supported by bearings 104, 105, 106, and the third intermediate case 102 side is connected to the first driven shaft 59. The second driven shaft 60 is spline-fitted to gears 75 and 81 pivotally supported by bearings 97 and 95, and the main drive shaft 58 is pivotally supported by a bearing 96. (See Figure 11)
The first driven shaft 59 is sub-assembled with the gears 69 and 71 and the cylinder case 74 in which the clutches C1 and C3 are incorporated, but is provided with retaining rings 107 and 109 for pressing the gear end face so that the cylinder case 74 is not detached. Similarly, the second driven shaft 60 is sub-assembled with the gears 67 and 73 and the cylinder case 80 in which the clutches C2 and C4 are incorporated, but is provided with retaining rings 110 and 108 for pressing the gear end faces so that they do not come off. Retaining rings 107, 108, 109, and 110 fitted at the end of the sub set have different end faces of the gears 67, 73, 69, and 71 from the cylinder cases 74 and 80. Also become.

  The hydraulic piping that operates the clutches C1 and C3 in the cylinder case 74 connects the oil passage 114 drilled in the third intermediate case 102 and the oil passage 111 drilled in the second intermediate case 101 together with the joining of the case. By providing the oil passage 111 on the intermediate case 101 side in the raised portion 112 and connecting to the oil passage 114 provided in the recessed portion 116 on the third intermediate case 102 side, the sealing material applied to the case end face prevents the oil passage. I am trying not to. Reference numeral 115 denotes an oil ring.

The oil path to the cylinder case 80 is the same.
A gear 75 spline-fitted to the lower end of the transmission of the first driven shaft 59 is engaged with a gear 76 fixed to a gear cylinder 77 loosely fitted to the main drive shaft 58 to rotate the first driven shaft 59 to the gear cylinder 77. It is transmitted.

  An output shaft 55 is provided on the axis of the first driven shaft 59, and a clutch gear 78 constituting the auxiliary transmission B is spline-fitted to the output shaft 55. The clutch gear 78 is a gear formed on the gear cylinder 77. When meshed with the gear 79, the rotation of the gear cylinder 77 is transmitted from the gear 79 to the output shaft 55 via the clutch gear 78, and when meshed with the gear 75 of the first driven shaft 59, the rotation of the first driven shaft 59 or the first described later. The rotation transmitted from the two driven shafts 60 to the gear 75 is transmitted to the output shaft 55.

  Accordingly, when the first-speed clutch C1 is turned on, the rotation of the main drive shaft 58 is decelerated from the gear 68 to the gear 69, and the rotation of the gear 69 becomes the rotation of the first driven shaft 59 via the cylinder case 74. The gear 75 is rotated. At this time, when the clutch gear 78 is engaged with the gear 75, the rotation of the first driven shaft 59 is directly transmitted to the output shaft 55, and when the clutch gear 78 is engaged with the gear 79 formed on the gear cylinder 77, the rotation of the gear 75 is performed. The gear 76 is decelerated and transmitted to the gear cylinder 77 via the gear 76, and is decelerated and transmitted from another gear 79 of the gear cylinder 77 to the output shaft 55.

  Further, when the third speed clutch C3 is turned on, the rotation of the main drive shaft 58 is transmitted at an increased speed from the gear 70 to the gear 71, and the rotation of the gear 71 is coupled with the rotation of the first driven shaft 59 via the cylinder case 74. The gear 75 is rotated. At this time, when the clutch gear 78 is engaged with the gear 75, the rotation of the first driven shaft 59 is directly transmitted to the output shaft 55, and when the clutch gear 78 is engaged with the gear 79 formed on the gear cylinder 77, the rotation of the gear 75 is performed. The gear cylinder 77 is decelerated and transmitted to the gear cylinder 77 via the gear 76, and the rotation is further decelerated and transmitted from another gear 79 of the gear cylinder 77 to the output shaft 55.

  A configuration similar to the gear transmission mechanism provided between the main drive shaft 58 and the first driven shaft 59 arranged in parallel is also provided between the main drive shaft 58 and the second driven shaft 60. Thus, a second-speed clutch C2 and a fourth-speed clutch C4 are configured.

  First, a gear 66 that is spline-engaged with the main drive shaft 58 is always meshed with a gear 67 that is supported by the second driven shaft 60 via a needle bearing, and the second driven shaft 60 is made relatively non-rotatable. A case 80 is attached. The cylinder case 80 includes a second-speed clutch C2 and a fourth-speed clutch C4.

  A gear 81 fixed to the rear end of the second driven shaft 60 is meshed with a gear 76 spline-fitted to a gear cylinder 77 loosely fitted to the main drive shaft 58 to transmit the rotation of the second driven shaft 60 to the gear cylinder 77. is doing.

  Therefore, when the second speed clutch C2 is turned on, the rotation of the main drive shaft 58 is transmitted at high speed from the gear 66 to the gear 67, and the rotation of the gear 67 becomes the rotation of the second driven shaft 60 via the cylinder case 80. The gear 81 is rotated, and the gear 75 is further rotated from the gear 81 through the gear 76. At this time, when the clutch gear 78 meshes with the gear 75, the rotation of the second driven shaft 60 is transmitted to the output shaft 55, and when the clutch gear 78 meshes with the gear 79 formed on the gear cylinder 77, the rotation of the gear 81 causes the gear 81 to rotate. The power is transmitted to the gear cylinder 77 via 76 and is decelerated from the gear 79 to the output shaft 55.

  Further, when the fourth-speed clutch C4 is turned on, the rotation of the main drive shaft 58 is increased in speed from the gear 72 to the gear 73, and the rotation of the gear 73 is coupled with the rotation of the second driven shaft 60 via the cylinder case 80. The gear 81 is rotated, and the gear 75 is further rotated from the gear 81 through the gear 76. At this time, when the clutch gear 78 meshes with the gear 75, the rotation of the second driven shaft 60 is transmitted to the output shaft 55, and when the clutch gear 78 meshes with the gear 79 formed on the gear cylinder 77, the rotation of the gear 81 causes the gear 81 to rotate. The power is transmitted to the gear cylinder 77 via 76 and is decelerated from the gear 79 to the output shaft 55.

  A support shaft 94 is pivotally attached to the left and right side walls of the rear case 103 that supports the left and right crawler travel devices 13, and a bevel gear 85 that meshes with the bevel gear 56 fixed to the output shaft 55 is spline-engaged with the support shaft 94. A brake disc 82 is provided at a position symmetrical to the bevel gear 85.

A reduction gear set 83 is provided at the end of the support shaft 94, and the rotation of the support shaft 94 is transmitted to the input shaft 84 in the axle case via the reduction gear set 83.
The main speed change lever 9 and the sub speed change lever 17 are appropriately operated to travel at a desired travel speed. The low speed of the sub speed change lever 17 is mainly used during operations such as rotary work, and the high speed of the sub speed change lever 17 is Use when traveling on the road.

The rotation of the main drive shaft 58 is transmitted to the PTO input shaft 91 connected to the shaft end, and is transmitted to the PTO output shaft 93 via the PTO transmission mechanism 92.
Then, the brake pedal 25 and the brake disc 82 are connected by a link mechanism (not shown), and the brake disc 82 is crimped by depressing the brake pedal 25, whereby the rotation of the support shaft 94, that is, the left and right crawler travel devices 13, It is comprised so that rotation of 13 may be braked.

  Inside the axle case, a turning device constituted by a forward / reverse clutch D and a two-stage planetary gear mechanism 87 is disposed. The swivel device is interposed between the input shaft 84, a sprocket shaft 86 that is coaxially attached to the input shaft 84 on the outer end side of the input shaft 84, and the input shaft 84 and the sprocket shaft 86. A two-stage planetary gear mechanism 87, and a wet multi-plate type forward rotation clutch 89 and a reverse rotation clutch 90 (forward / reverse clutch D) provided on a carrier 88 of the two-stage planetary gear mechanism 87, It is provided on the left and right sides of the axle case.

  When the forward rotation clutch 89 is engaged, it rotates forward, and when the reverse rotation clutch 90 is engaged, it rotates backward, but the forward rotation clutch 89 is engaged by spring pressure and the forward / reverse lever 24 is moved backward. Is operated so that the oil pressure is applied to the clutch plate and the reverse clutch 90 is switched on. When the spring pressure and the oil pressure are balanced and the forward clutch 89 and the reverse clutch 90 become neutral, the sprocket shaft 86. The power transmission to is lost, and the sprocket shaft 86 stops.

  The left and right forward clutch D reads the rotation of the steering handle 15 with a sensor and controls the hydraulic pressure with the controller 125 so that the inner sprocket shaft 86 stops and the outer sprocket shaft 86 rotates to rotate. become.

Further, the forward / reverse clutch D operates as follows by the operation of the clutch pedal (clutch operating tool) 26 and the brake pedal (brake operating tool) 25.
As shown in FIG. 12, a clutch sensor 133 (corresponding to the traveling sensor S of the present invention) including a potentiometer 119 for detecting the rotation angle of the arm 118 projecting from the boss is provided near the pivot shaft 117 of the clutch pedal 26. Yes. Similarly, although not shown, a brake sensor 131 (corresponding to the traveling sensor S of the present invention) including a potentiometer that detects a rotation angle is provided near the pivot shaft of the brake pedal 25.

  The clutch sensor 133 may be provided at a position for detecting the movement of the link connecting the clutch pedal 26 and the main clutch 52, and the brake sensor 131 also detects the movement of the link or brake cam connecting the brake pedal 25 and the brake disc 82. You may provide in the position to detect.

  FIG. 13 is a control block diagram of the controller 125. The depression angle of the brake pedal 25 from the brake sensor 131, the depression angle of the clutch pedal 26 from the clutch sensor 133, and the forward / reverse switching of the forward / reverse switching lever 24 from the forward / reverse switch 132. The position is input to the controller 125 by an on / off switching signal from the automatic control switch 134 and the traveling speed of the aircraft from the vehicle speed sensor 135. From the controller 125, an operation signal for turning on / off the main clutch 52, an operation signal for forward, neutral, reverse, and half-clutch are transmitted to the forward / reverse clutch D, and an automatic control state display signal is displayed to the monitor 137. The abnormality warning lamp 42 outputs the failure state of each sensor. The forward / reverse storage circuit 138 stores the shift position before the current shift position.

FIG. 14 is a control flowchart of the forward / reverse clutch D in the controller 125 according to the operation position of the travel operation tool E (brake operation tool 25).
In step S1, data such as the brake sensor 131 and the clutch sensor 133 are read. In step S2, it is determined whether the automatic control switch 134 is turned on. If YES, the automatic control state in step S3 is displayed on the monitor 137. If so, the process proceeds to the normal control in step S12.

  When the data such as the brake sensor 131 and the clutch sensor 133 output an abnormal value to the controller 125 when the data is read in step S1, the system abnormality warning lamp 38 is turned on and the traveling is immediately stopped.

  After step S3, it is determined in step S4 whether the current traveling speed is a low speed of 1.5 km / h or less. If YES, the process proceeds to step S5, and if NO, the process proceeds to normal control in step S12.

  In step S5, it is determined that the clutch pedal 26 is depressed. If the output of the clutch sensor 133 is zero, that is, if there is no depression, the process proceeds to step S6, and if there is, the process proceeds to normal control in step S12.

  In step S6, it is determined whether the brake pedal 25 is depressed. If the output of the brake sensor 131 is not zero, that is, if the brake pedal 25 is depressed, the process proceeds to step S7. Migrate to

  In step S7, the position of the forward / reverse switching lever 24 is determined. If the forward / reverse switch 132 is neutral, the process proceeds to step S8. If the forward / reverse switch is not neutral, the forward / reverse travel currently turned on in step S10. The clutch D is set to the half clutch state, and the process proceeds to step S13.

  In step S8, it is determined whether the shift position before neutralization is forward. If forward, forward rotation clutch 89 is set to a half clutch in step S9. If reverse, reverse rotation clutch 90 is set to half in step S11. The clutch is engaged and the process proceeds to step S13. By doing so, the clutch in the traveling direction is changed to a half-clutch, and it is not difficult.

In step S13, the main clutch 52 is disengaged. In step S14, the forward clutch 89 is turned on. In step S15, the brake disc 52 is braked and completely stopped.
As described above, when the traveling is stopped, the power transmission of the traveling system is braked by turning off the power while the forward / reverse clutch D is used as a half-clutch, so that the engine 11 is driven with almost no stop load. Does not fluctuate.

  FIG. 15 is a control flowchart for starting traveling. In step S20, the detection data of the clutch sensor 133 and the forward / reverse switch 132 are read. In step S21, the detected value of the clutch sensor 133 is not zero, and the clutch pedal 26 is depressed. In step S22, it is determined whether or not the forward / reverse switch 132 is moving forward or backward. If YES, the forward or reverse forward / reverse clutch D currently turned on is determined in step S23. In the half-clutch state, the main clutch 52 is engaged in step S24, and the driving force of the engine 11 is transmitted to the crawler traveling device 13 to start. If the determinations in step S21 and step S22 are NO, the travel is not started and the process ends without doing anything.

FIG. 16 is a flowchart of normal control.
In step S30, it is determined whether the brake pedal 25 is depressed. If the output of the brake sensor 131 is not zero, that is, if it is depressed, the main clutch 52 is disconnected in step S31, and the shift position of the forward / reverse lever 24 is neutral in step S32. Determine if there is any. If this neutral determination is YES, that is, neutral, the forward clutch is engaged in step S33 to activate the brake disc 82, and the brake brake disc 82 is braked and stopped in step S34. If it is other than neutral in step S32, the forward / reverse clutch D is engaged and the brake disc 82 acts, so the brake disc 82 is immediately braked and stopped in step S34.

17 to 20 show the structure of the seat interposed between the mating surfaces of the blocks constituting the hydraulic valve.
In FIG. 17, bolt holes 141, 142, 143, and 144 are provided at the four corners of the seat 140, and the bead (slightly raised portion is surrounded by the oil port 150 near the bolt holes 141, 142, 143, and 144). ) 14, 15, 146, 147, 148 are provided. With this configuration, it is possible to eliminate the distortion of the spool sliding portion that is likely to occur when the block is assembled.

18 is different from FIG. 16 in the positions and ranges of the beads 145, 146, 147, and 148.
19 is characterized by a bead 151 surrounding the bolt holes 141, 142, 143, and 144, a bead 148 surrounding the oil port 150, and a bead 149 provided near the outer periphery of the seat 140.

  In FIG. 20, the seat 140 is configured only by the beads 151 surrounding the bolt holes 141, 142, 143, and 144 and the beads 148 surrounding the oil port 150.

It is a side view of the tractor which shows the Example of this invention. It is a partial perspective view of a tractor. It is a partial enlarged plan view of a tractor. It is a partial enlarged plan view of a tractor. 1 is an overall perspective view of a tractor. It is a partial top view of a tractor. It is a partial perspective view of a tractor. It is a power transmission diagram of a tractor. It is a whole sectional side view of a mission case. It is a front sectional view of a mission case. It is a partially expanded side sectional view of a mission case. It is a flowchart figure of control. It is a flowchart figure of control. It is a block diagram of control. It is a flowchart figure of control. It is a flowchart figure of control. It is a partial enlarged plan view. It is a partial enlarged plan view. It is a partial enlarged plan view. It is a partial enlarged plan view.

Explanation of symbols

13 Crawler traveling device 52 Main clutch D Forward / reverse clutch E Traveling operation tool (clutch operation tool 26, brake operation tool 25)
S traveling sensor (brake sensor 131, clutch sensor 133)

Claims (3)

In a crawler traveling vehicle provided with a forward / reverse clutch (D) operated by hydraulic drive in a drive system of the crawler traveling device (13), a traveling sensor (S) for detecting an operation amount of the traveling operation tool (E) is provided, A traveling operation device for a crawler traveling vehicle characterized in that the traveling speed is controlled by setting the forward / reverse clutch (D) in a half-clutch state based on the output of the traveling sensor (S). The travel operation tool (E) is a clutch operation tool (26) for operating the main clutch (52), and the clutch operation tool (26) is engaged to engage the clutch, while the forward / reverse clutch (D) is in a half-clutch state. The traveling operation device for a crawler traveling vehicle according to claim 1, wherein the traveling operation device is configured as follows. The travel operation tool (E) is a brake operation tool (25) that decelerates the travel speed. As the brake operation tool (25) is braked, the main clutch (52 The crawler traveling vehicle traveling operation device according to claim 1, wherein the braking operation state is set to a brake braking state.

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