JP7254679B2 - Shaft seal structure and work machine equipped with said seal structure - Google Patents

Description

The present invention relates to a shaft seal structure and a work machine such as a wheel loader having the seal structure.

Conventionally, a shaft seal structure disclosed in Patent Document 1 is known.
In the shaft seal structure disclosed in Patent Document 1, a groove is formed in the inner peripheral surface of a cylindrical member arranged on the outer peripheral side of the shaft, an O-ring is fitted in the groove as a sealing member, and the O-ring is attached to the shaft. is in contact with the outer peripheral surface of the

Japanese Patent Application Laid-Open No. 2002-206691

However, in the seal structure described above, it is necessary to machine a groove for fitting the O-ring in the inner peripheral surface of the cylindrical member. Also, the O-ring is not easy to assemble because it needs to be compressed and fitted into the groove.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a shaft seal structure capable of exhibiting excellent sealing performance and facilitating assembly of a seal member.

A shaft seal structure according to an aspect of the present invention includes a shaft, a cover having an opening through which the shaft is inserted, and a sealing material that seals between an outer peripheral surface of the shaft and an opening edge of the opening. , wherein the shaft is movable relative to the cover in the axial direction of the shaft, and the seal member includes an inner edge portion that is in close contact with the outer peripheral surface of the shaft due to elastic deformation, and the opening portion. an outer edge portion attached to the opening edge of the inner edge portion is formed in a curved surface shape bulging toward the outer peripheral surface, and the outer edge portion has a groove into which the opening edge is fitted. formed.

According to the above configuration, the sealing material has an inner edge that is in close contact with the outer peripheral surface of the shaft due to elastic deformation, and the inner edge is formed in a curved surface that protrudes toward the outer peripheral surface. Sealing performance can be demonstrated. In addition, the sealing material has an outer edge to be attached to the opening edge of the opening of the cover, and the outer edge is formed with a groove into which the opening edge is fitted, thus facilitating assembly of the sealing material. It can be carried out.

It is a side view of a working machine. It is a top view of a working machine. It is the perspective view which looked at the floor frame from the back upper part. It is the side view which looked at the steering column, the adjustment device, etc. from the right side. It is the figure which looked at the steering column, the adjusting device, the brake pedal, etc. from the rear side (driver's seat side). It is the figure which looked at the steering column, the adjustment device, the brake pedal, etc. from the front side (driver's seat and opposite side). FIG. 4 is a cross-sectional view of the support structure for the brake pedal; It is a figure which shows the state in which a rocking|swiveling member exists in a 1st position, and the state in which it exists in a 2nd position. It is a perspective view which shows the relationship between a brake arm and a cable. FIG. 4 is a configuration diagram showing an inching valve attachment portion and a travel system hydraulic circuit; FIG. 4 is a side view of the mounting portion of the inching valve; FIG. 4 is a perspective view of a mounting portion of the inching valve; FIG. 4 is a vertical cross-sectional view of the adjusting device and the cover; FIG. 3 is an exploded perspective view of part of the adjustment device; FIG. 4 is a vertical cross-sectional view of part of the adjustment device, showing a state in which the engaging member is engaged with the first engaging portion and the second engaging portion; FIG. 15B is a partially enlarged view of FIG. 15A; Fig. 10 is a side view of part of the adjustment device; FIG. 4 is a longitudinal sectional view of part of the adjustment device, showing a state in which the engaging member engages with the first engaging portion and disengages from the second engaging portion; FIG. 4 is a longitudinal cross-sectional view of a portion of the adjustment device, showing the engaging member engaged with the first engaging portion and another second engaging portion; FIG. 5 is a diagram showing the swinging of the swinging member accompanying the movement of the outer shaft; FIG. 17 is a side view of part of the adjustment device, showing the state in which the outer shaft has been rotated from the state shown in FIG. 16; It is the perspective view which looked at the cover and the adjustment device from the right front. FIG. 4 is a perspective view of the cover and adjustment device as seen from the right rear; Fig. 10 is a perspective view of the cover and adjustment device as seen from the left front; It is a perspective view of a sealing material.

An embodiment of the present invention will be described below with appropriate reference to the drawings.
FIG. 1 is a schematic side view showing the overall configuration of a working machine 1 according to this embodiment. FIG. 2 is a schematic plan view of the working machine 1. FIG. In this embodiment, a wheel loader is exemplified as the working machine 1 .
As shown in FIGS. 1 and 2, the wheel loader of this embodiment is an articulated work machine 1, and the body 2 of the work machine 1 is composed of a front body 2A and a rear body 2B. . The front body 2A is provided with a left front wheel 3L and a right front wheel 3R. The front wheel 3L is provided on the left side of the front body 2A, and the front wheel 3R is provided on the right side of the front body 2A. The rear body 2B is provided with a left rear wheel 4L and a right rear wheel 4R. The rear wheel 4L is provided on the left side of the rear body 2B, and the rear wheel 4R is provided on the right side of the rear body 2B. The front wheels 3L, 3R and the rear wheels 4L, 4R form part of a travel device 17 that supports the body 2 so that it can travel. The rear body 2B is equipped with a driver's seat (seat) 13 on which an operator (driver) sits. The driver's seat 13 is arranged between the rear wheels 4L and 4R, and is provided at the center of the body 2 in the body width direction K2.

In this embodiment, the front side of the operator seated in the driver's seat 13 (direction of arrow A1 in FIGS. 1 and 2) is forward, the rear side of the operator (direction of arrow A2 in FIGS. 1 and 2) is rearward, and the left side of the operator. (Front side in FIG. 1, direction of arrow B1 in FIG. 2) is defined as left side, and operator's right side (back side in FIG. 1, direction of arrow B2 in FIG. 2) is defined as right side.
Also, the horizontal direction perpendicular to the fuselage longitudinal direction K1 will be described as the fuselage width direction K2 (see FIG. 2). Also, the direction toward the right or left from the central portion in the width direction of the fuselage 2 will be described as the outward direction of the fuselage. That is, the outer side of the fuselage is a direction away from the center of the fuselage 2 in the fuselage width direction K2. The direction opposite to the outer side of the fuselage will be described as the inner side of the fuselage. In other words, the inward direction of the fuselage is a direction approaching the center of the fuselage 2 in the fuselage width direction K2.

As shown in FIG. 1, a body connecting member 5 is provided on the front end side of the rear body 2B so as to be rotatable within a predetermined range about an axis in the longitudinal direction K1 of the body. The side is connected so as to be swingable in the body width direction K2 around the vertical axis (the axis extending in the vertical direction).
A steering cylinder 6 composed of a hydraulic cylinder is provided across the body connecting member 5 and the front body 2A. By extending and contracting the steering cylinder 6, the front body 2A swings relative to the rear body 2B in the body width direction K2, so that the working machine 1 can turn left and right.

A cabin 14 as a driver's seat protection device surrounding a driver's seat 13 is provided in the rear fuselage 2B. A steering wheel (steering) 15 for operating a steering cylinder 6 forming a part of the travel device 17 and a control lever 16 for operating the working device 7 are provided in the cabin 14 . The steering wheel 15 is arranged in front of the driver's seat 13 , and the control lever 16 is arranged to the side (right side) of the driver's seat 13 .

As shown in FIG. 1, a prime mover 352 is mounted on the rear airframe 2B. Prime mover 352 is, for example, a diesel engine. A canopy may be used instead of the cabin 14 as the driver's seat protection device.
As shown in FIGS. 1 and 2, a working device 7 (front working device) is provided on the front body 2A. The working device 7 has a lift arm 8 supported by the front body 2A (body 2) so as to be vertically swingable. The lift arm 8 has a left first arm 8L and a right second arm 8R spaced apart in the body width direction K2. The base end side (rear end side) of the first arm 8L is rotatably supported on the upper part of the first support frame 10L erected on the left side of the front body 2A about an axis extending in the body width direction K2. ing. Therefore, the first arm 8L can swing up and down. The base end of the second arm 8R is rotatably supported on an upper portion of a second support frame 10R erected on the right side of the front body 2A about an axis extending in the body width direction K2. Therefore, the second arm 8R can also swing up and down. A work light 33L is provided on the upper left side of the first support frame 10L. A work light 33R is also provided on the upper right side of the second support frame 10R.

As shown in FIGS. 1 and 2, the first arm 8L and the second arm 8R are connected by a connecting pipe 26 provided in the middle of the lift arm 8 in the longitudinal direction.
As shown in FIG. 1, a lift cylinder 11L is provided across the longitudinal middle portion of the first arm 8L and the vertical middle portion of the first support frame 10L. A lift cylinder 11R is provided between the longitudinal middle portion of the second arm 8R and the vertical middle portion of the second support frame 10R. The lift cylinder 11L and the lift cylinder 11R are composed of double-acting hydraulic cylinders. By extending and contracting the lift cylinder 11L and the lift cylinder 11R, the lift arm 8 (the first arm 8L and the second arm 8R simultaneously) swings up and down.

As shown in FIGS. 1 and 2, the working device 7 has a working tool 9 detachably attached to the front portion of the lift arm 8 . The work tool 9 is equipped with a bucket as standard equipment, and instead of the bucket, a work tool (attachment) such as a pallet fork, a mania fork, or a work tool (hydraulic attachment) having a hydraulic actuator such as a sweeper, a mower, or a breaker can be used. can be installed. A lower back surface of the work tool 9 is connected to and pivotally supported on the tip side (front end side) of the lift arm 8 .

As shown in FIG. 1 , the work implement 1 has a work implement cylinder 12 that drives a work implement 9 . The work tool cylinder 12 is composed of a double-acting hydraulic cylinder. A bracket member 27 is fixed to the connecting pipe 26 , and the vertical middle portion of the swing link 28 is pivotally supported by the bracket member 27 . One end of the work implement cylinder 12 is connected to the upper portion of the swing link 28 . The other end of the work implement cylinder 12 is pivotally supported by a bracket member 30 provided on a connecting member 29 that connects the first support frame 10L and the second support frame 10R (see FIG. 2). A rear portion of an interlocking link 31 is pivotally supported on a lower portion of the rocking link 28 . The front portion of the interlocking link 31 is pivotally supported (engaged) with the upper back surface of the work implement 9 . By extending and contracting the work implement cylinder 12, the swing link 28 swings and the interlocking link 31 moves back and forth. As a result, the work implement 9 swings up and down around the connection point with the lift arm 8 .

The front wheel 3L is provided in front of the first support frame 10L and to the left of the first arm 8L. Further, the front wheel 3L is positioned behind the left portion of the work tool 9. As shown in FIG. The front wheel 3R is provided forward of the second support frame 10R and to the right of the second arm 8R. Further, the front wheel 3R is positioned behind the right portion of the work tool 9. As shown in FIG.
As shown in FIG. 1 , the rear portion of the fuselage 2 is provided with a bonnet 301 that covers the prime mover 352 from above and a weight 302 that is arranged below the bonnet 301 .

As shown in FIG. 1 , a steering column 87 that supports the steering wheel 15 is provided in the front part of the interior of the cabin 14 . The steering column 87 is positioned at the center of the interior of the cabin 14 in the machine width direction K2.
The steering column 87 has a column frame (frame member) 88 shown in FIG. As shown in FIG. 3 , the column frame 88 is erected on the front portion of the floor frame 72 forming the lower portion of the cabin 14 . The floor frame 72 has a left first side wall 73L and a right second side wall 73R. A bottom wall 74 is provided between the lower portions of the first side wall 73L and the second side wall 73R. The floor frame 72 has a floor portion (step) 75 provided on the front side of the bottom wall 74 . The bottom wall 74 is positioned below the floor 75 . Therefore, a space is provided between the front end side of the bottom wall 74 and the rear end side of the floor portion 75 . A rubber mat 332 is laid on the floor 75 (see FIGS. 4 to 6).

As shown in FIG. 3, the column frame 88 is provided at the center of the front portion of the floor frame 72 in the body width direction K2. The column frame 88 has a first side wall 88L and a second side wall 88R spaced apart in the body width direction K2. The first side wall 88L constitutes the left portion of the column frame 88 and stands on the floor portion 75. As shown in FIG. The second side wall 88</b>R constitutes the right portion of the column frame 88 and stands upright on the floor portion 75 .

As shown in FIG. 6 , the column frame 88 has a first connecting member 83 and a second connecting member 84 . The first connecting member 83 connects the upper portions of the rear portions of the first side wall 88L and the second side wall 88R. The second connecting member 84 connects the vertical middle portions of the first side wall 88L and the second side wall 88R. A steering valve 90 for controlling the steering cylinder 6 is arranged below the second connecting member 84 .

As shown in FIGS. 4 to 6, the steering column 87 has a column cover 89 that covers the column frame 88. As shown in FIGS. The column cover 89 covers the front and top of the column frame 88 .
As shown in FIG. 6, a brake pedal 111 is arranged on the left side of the column frame 88 . A brake shaft 112 having an axis extending in the body width direction K2 is provided on the top of the column frame 88 . The brake shaft 112 is made of a single rod, passes through the upper and front portions of the first side wall 88L and the second side wall 88R, and is supported by these side walls 88L and 88R so as to be rotatable about the axis.

A left portion of the brake shaft 112 protrudes leftward from a bearing boss 113 fixed to the outside of the first side wall 88L. An upper portion 114L of the brake pedal 111 is fixed to this projecting portion. Therefore, the brake pedal 111 rotates integrally with the brake shaft 112 . Below the brake pedal 111 is provided a stepping portion 115 that is stepped on by an operator. That is, the brake pedal 111 is a suspension type brake pedal.

As shown in FIG. 7, the right portion of the brake shaft 112 protrudes outward from the second side wall 88R. A rocking member 501 that rocks in conjunction with the brake pedal 111 is attached to the right portion of the brake shaft 112 . As shown in FIG. 8, the rocking member 501 has a mounting portion 502 attached to the right portion of the brake shaft 112 on the base end side, and a contact portion 503 on the distal end side with which a moving member 504 to be described later abuts. are doing. The rocking member 501 rotates integrally with the brake shaft 112 as the brake pedal 111 is operated, thereby rocking around the central axis of the brake shaft 112 (see arrow C1 in FIG. 8). Specifically, as shown in FIG. 8, the swing member 501 swings between the first position P1 and the second position P2 as the brake pedal 111 is operated.

Further, the position of the brake pedal 111 can be changed by swinging the swing member 501 to change the position.
As shown in FIG. 7, the brake shaft 112 has a connection 116 formed by a spline on its right side. The coupling portion 116 is formed up to the right end of the brake shaft 112 . A bushing 117 that supports the brake shaft 112 is fixed to the inner upper portion of the second side wall 88R. The bushing 117 penetrates the second side wall 88R and protrudes inward from the second side wall 88R. The bushing 117 has openings at both ends in the axial direction, and the coupling portion 116 is inserted through the bushing 117 . Coupling portion 116 protrudes from the left end of bushing 117 . A brake arm 118 is arranged to the left of the bushing 117 . Brake arm 118 has an arm boss 119 fitted to coupling portion 116 and an arm portion 120 fixed to arm boss 119 . Arm boss 119 is spline-connected to connecting portion 116 and rotates integrally with brake shaft 112 . The arm boss 119 also has a bearing portion 119 a that is inserted into the bushing 117 . The brake shaft 112 is supported by the bushing 117 via the bearing portion 119 a and the bush 121 .

As shown in FIG. 7, the connecting portion 116 has a projecting portion 116a projecting from the right end portion of the bushing 117 to the outside of the vehicle body (the side opposite to the side where the brake pedal 111 is arranged). A boss 114R provided on the upper portion of the swing member 501 is attached to the projecting portion 116a. The boss 114R rotates integrally with the brake shaft 112 by being fitted into the projecting portion 116a from the right side and spline-coupled. The boss 114R has a pivot portion 132 that is inserted into the bushing 117. As shown in FIG. A bushing 133 provided on the inner peripheral side of the bushing 117 is fitted to the outer periphery of the shaft support portion 132 . The brake shaft 112 is supported by the bushing 117 via a shaft support portion 132 and a bushing 133 .

As shown in FIG. 7 , a retainer plate 505 is fixed to the right end of the brake shaft 112 with a fixture (bolt) 506 . The pressing plate 505 is in contact with the right end surface of the brake shaft 112 and the right end surface of the boss 114R.
As shown in FIG. 9 , one end of a connecting link 122 is pivotally supported on the rear portion of the arm portion 120 , and the other end of the connecting link 122 is connected to the upper portion of the piston rod 124 of the master cylinder 123 . Therefore, by depressing the brake pedal 111 , the rear portion of the brake arm 118 swings downward as the brake shaft 112 rotates, and the piston rod 124 is pushed through the connecting link 122 . As a result, the master cylinder 123 operates, and the braking device (not shown) operates.

As shown in FIG. 9, the arm portion 120 is provided with a first contact portion 120a and a second contact portion 120b. A regulating rod 129 is provided between the first contact portion 120a and the second contact portion 120b. As shown in FIG. 6, the regulation rod 129 is fixed to the second side wall 88R so as to protrude inward of the fuselage. The contact of the first contact portion 120a with the regulating rod 129 restricts the swinging of the brake pedal 111 in the direction opposite to the depression direction (counter-depression direction). The position of the brake pedal 111 when the first contact portion 120a is in contact with the regulating rod 129 is the position before the brake pedal is depressed. Further, the second contact portion 120b abuts against the regulating rod 129, thereby regulating the rocking motion of the brake pedal 111 in the depression direction.

The stroke of the operation of the brake pedal 111 is defined in the range between the position restricted by the first contact portion 120a and the position restricted by the second contact portion 120b. That is, the position of the brake pedal 111 restricted by the first contact portion 120 a is the initial position of the stroke of the brake pedal 111 . The position of the brake pedal 111 that is regulated by the second contact portion 120b is the final position of the stroke of the brake pedal 111 .

When the brake pedal 111 is at the initial stroke position, the rocking member 501 is at the first position P1 (see FIG. 8). When the brake pedal 111 is at the final stroke position, the swinging member 501 is at the second position P2 (see FIG. 8).
However, the first position P1 can be changed by an adjusting device 511, which will be described later, and by changing the first position P1, the initial position of the stroke of the brake pedal 111 can be adjusted. The range in which this adjustment is possible is the range between the position restricted by the first contact portion 120a and the position restricted by the second contact portion 120b.

As shown in FIG. 6, a return spring 131 is arranged on the right side between the first side wall 88L and the second side wall 88R to return the brake pedal 111 to the position before being operated (set position when not operated). . The return spring 131 is composed of a torsion coil spring and is provided so as to surround the brake shaft 112 . In this embodiment, the return spring 131 is provided so as to surround the outer circumference of the bushing 117 . One end (left end) 131a of the return spring 131 is engaged with the brake arm 118 (see FIG. 9). The other end (right end) 131 b of the return spring 131 is hooked on the regulating rod 129 . As a result, the return spring 131 urges the brake pedal 111 in the anti-depression direction.

As shown in FIG. 9, a connecting rod 335 is fixed to the distal end side of the arm portion 120 so as to protrude outward from the body. One end of the cable 336 is pivotally connected to one end of the connecting rod 335 (outer end of the fuselage). Specifically, the cable 336 has an inner cable 336A and an outer cable 336B, and one end of the inner cable 336A is connected to the connecting rod 335. As shown in FIG. A first cable stay 337 is fixed to the surface of the second side wall 88R on the inner side of the fuselage. The first cable stay 337 is provided at the rear and lower portion of the second side wall 88R. One end of the cable 336 is attached to the first cable stay 337 . Specifically, an outer cable 336B is attached to the first cable stay 337 .

The cable 336 is a cable that interlocks and connects the brake arm 118 (brake pedal 111) and an inching valve (valve) 338 (see FIGS. 9 and 10).
As shown in FIG. 11, the inching valve 338 is arranged on the front end side and below the bottom wall 74 of the floor frame 72 . An inching valve 338 is attached to the bottom wall 74 below the driver's seat 13 . FIG. 10 is a bottom view of the floor frame 72 viewed from below. As shown in FIG. 10, inching valve 338 is located on the right side of bottom wall 74 .

As shown in FIG. 12, the inching valve 338 is mounted on a valve bracket 339 which is mounted on a mounting bracket 340 fixed to the bottom wall 74 . The valve bracket 339 has a valve mounting portion 339a to which the inching valve 338 is mounted, and a bracket mounting portion 339b extending upward from the valve mounting portion 339a. The mounting bracket 340 is fixed to the top surface of the bottom wall 74 so that the front end slightly protrudes from the front end of the bottom wall 74 . The mounting bracket 340 includes a mounting wall 340a erected on the bottom wall 74 so that the mounting surface (front surface) faces forward, and a first side wall 340b extending rearward from one end side of the mounting wall 340a in the machine width direction K2. , and a second side wall 340c extending rearward from the other end side of the mounting wall 340a in the body width direction K2. The upper part of the bracket attachment portion 339b is superimposed on the front surface of the attachment wall 340a and attached with bolts 341. As shown in FIG.

As shown in FIG. 12, a second cable stay 342 to which the other end of the cable 336 is attached is attached to the bracket attachment portion 339b. The second cable stay 342 has a first wall portion 342a, a second wall portion 342b, and a third wall portion 342c. The first wall portion 342a is superimposed on the front surface of the bracket mounting portion 339b and fixed by bolts 343. As shown in FIG. The second wall portion 342b extends forward from the end of the first wall portion 342a on the outer side of the aircraft body. The third wall portion 342c extends inward from the second wall portion 342b. Specifically, the third wall portion 342c extends in an inclined direction moving forward toward the inside of the fuselage. An outer cable 336B is attached to the third wall portion 342c.

As shown in FIG. 12, the inching valve 338 has a valve body 338A having a rectangular block shape and a valve lever 338B for operating the valve body 338A. The valve body 338A is horizontally attached to the valve bracket 339. As shown in FIG. The valve body 338A has a first connecting portion 346 on the rear surface 338a, a second connecting portion 347 on one side surface (left side surface) 338b, and an operating shaft 345 on the upper surface 338c side.

As shown in FIG. 10 , the first connection portion 346 is connected to a discharge circuit 351 of a hydraulic pump 349 via a hydraulic hose (first hydraulic hose) 350 . The hydraulic pump 349 is, for example, a constant displacement pump, which is connected to the side of the prime mover 352 and driven by the power of the prime mover 352 . Also, the hydraulic pump 349 discharges hydraulic oil stored in a hydraulic oil tank (tank) 344 . Specifically, the hydraulic pump 349 discharges hydraulic oil (pilot oil) for hydraulically controlling the hydraulic drive device 353 . The hydraulic oil tank 344 is arranged on the left side of the inching valve 338 (on the side where the second connecting portion 347 is provided). The second connection portion 347 is connected to the hydraulic fluid tank 344 via a hydraulic hose (second hydraulic hose) 354 .

The hydraulic drive device 353 is composed of, for example, an HST (Hydro Static Transmission), and drives the traveling device 17 by hydraulic pressure. More specifically, the hydraulic drive system 353 of this embodiment includes an HST pump 355, which is a swash plate type variable displacement pump driven by the power of a prime mover 352, and a closed circuit connection between the HST pump 355 and a pair of oil passages 356a and 356b. and an HST motor 357 that drives the traveling device 17 by being driven by the oil discharged from the HST pump 355 .

The HST pump 355 can change the direction of the hydraulic fluid to be discharged by swinging the swash plate 355A swinging from the neutral position to one side and the other side. The HST motor 357 is switched in rotation direction by discharging hydraulic oil from the HST pump 355 to the oil passage 356a or the oil passage 356b, and outputs forward drive power or reverse drive power to the travel device 17. FIG.
The hydraulic drive 353 has a servo cylinder 358 that sets the angle of the swash plate 355 A of the HST pump 355 . The servo cylinder 358 is connected to a forward/reverse switching valve 359 by a forward oil passage 360 and a reverse oil passage 361 . The forward/reverse switching valve 359 is connected to the discharge circuit 351 of the hydraulic pump 349 through the supply oil passage 362 and is connected to the hydraulic oil tank 344 through the tank oil passage 363 .

When the pilot oil is supplied from the forward/reverse switching valve 359 to the forward oil passage 360 , the servo cylinder 358 swings the swash plate 355 A toward the forward direction so that the pilot oil is supplied from the forward/reverse switching valve 359 to the reverse oil passage 361 . When the pilot oil is supplied, the swash plate 355A is swung backward, and when the pilot oil is not supplied to the forward oil passage 360 and the reverse oil passage 361, the swash plate 355A is held at the neutral position.

The valve body 338A (inching valve 338) is formed by a rotary valve, and the operating shaft 345 is integrally formed (or formed separately and connected to) the rotary spool of the valve body 338A. The operating shaft 345 is rotatable about the vertical axis, and by rotating about the vertical axis, the inching valve 338 is switched between an OFF state (closed state) and an ON state (open state). When the inching valve 338 is in the off state (closed state), the rotary spool of the valve body 338A is in the first position 3381 (see FIG. 10). When the inching valve 338 is in the on state (open state), the rotary spool of the valve body 338A is in the second position 3382 (see FIG. 10).

When the inching valve 338 is switched to the OFF state, the connection oil passage connecting the first connection portion 346 and the second connection portion 347 is cut off. As a result, the pilot oil discharged from the hydraulic pump 349 can be supplied to the forward/reverse switching valve 359, and the swash plate 355A swings forward or backward according to switching of the forward/reverse switching valve 359. When the inching valve 338 is switched to the ON state (open state), the connection oil passage connecting the first connection portion 346 and the second connection portion 347 is opened. As a result, the pilot oil discharged from the hydraulic pump 349 is discharged to the hydraulic oil tank 344 and is not supplied to the forward/reverse switching valve 359 . At this time, if the swash plate 355A is swinging forward or backward, the swash plate 355A moves to the neutral side, and the travel device 17 decelerates or stops. Since the valve opening of the inching valve 338 changes depending on the rotation angle of the operating shaft 345 (because the amount of pilot oil discharged to the hydraulic oil tank 344 changes), the deceleration of the traveling device 17 is controlled by the inching valve 338. can be adjusted by

As shown in FIG. 12, one end of the valve lever 338B is clamped and fixed to the operating shaft 345. As shown in FIG. Therefore, the valve lever 338B can rotate together with the operation shaft 345 about the vertical axis (the axis of the operation shaft 345). The other end of the cable 336 is connected to the other end of the valve lever 338B. Specifically, the other end of the inner cable 336A is connected to the other end of the valve lever 338B. Therefore, the inching valve 338 is interlocked with the brake pedal (pedal) 111 via the cable 336 .

When the brake pedal 111 is not depressed, the valve lever 338B protrudes forward from the operating shaft 345, as shown in FIG. 12, and the inching valve 338 is off.
When the brake pedal 111 is depressed, the brake arm 118 (arm portion 120) swings downward, pushing the cable 336 (inner cable 336A). Then, the valve lever 338B is pushed by the cable 336 and rotates together with the operation shaft 345 around the vertical axis. That is, when the brake pedal 111 is stepped on, the valve lever 338B swings leftward about the vertical axis (the axis of the operation shaft 345) to rotate the operation shaft 345. As shown in FIG. As a result, the inching valve 338 is turned on, the swash plate 355A is returned to the neutral position, and power is not output from the hydraulic drive device 353 to the traveling device 17. Therefore, by stepping on the brake pedal 111, the brake device is operated to brake the traveling device 17 and the hydraulic drive device 353 is brought into the neutral state.

As shown in FIG. 11 , a seat base 76 is attached to the bottom wall 74 , and the driver's seat 13 is attached to the seat base 76 . Specifically, the driver's seat 13 is attached to a suspension device 364 attached to the seat base 76 . The seat base 76 has an upper wall 76a and a front wall 76b extending downward from the front end of the upper wall 76a. A mounting wall 76c extends from the lower end of the front wall 76b and is fixed to the front portion of the bottom wall 74 with bolts. The seat base 76 has a support leg 76d to which an opening/closing cover 78 is attached. Specifically, the support leg 76d extends upward from the front end of the mounting wall 76c and has an upper portion bent forward. The rear portion of the opening/closing cover 78 is detachably attached to the upper portion of the support leg 76d by bolts or the like. A mounting bracket 340 , an inching valve 338 , a valve bracket 339 and a second cable stay 342 are arranged below the rear portion of the opening/closing cover 78 .

As shown in FIGS. 4 and 5 , the work machine 1 includes an adjustment device 511 that adjusts the stroke of operation of the brake pedal (pedal) 111 .
As shown in FIG. 13, the adjusting device 511 has the rocking member 501, the moving member 504, and the switching mechanism 512 described above.
The moving member 504 is movable in contact with the swinging member 501 . Specifically, the moving member 504 is movable in contact with the contact portion 503 of the swing member 501 . The moving member 504 changes the first position P1 (see FIG. 8) of the swinging member 501 by moving in contact with the swinging member 501 .

As shown in FIGS. 14 and 15A, the moving member 504 is composed of a cylindrical outer shaft (hereinafter referred to as "outer shaft 504"). As indicated by arrow D in FIG. 15A, outer shaft 504 is movable in the axial direction (direction along central axis X1 of outer shaft 504). Further, as indicated by arrow F in FIG. 15A, outer shaft 504 is rotatable around central axis X1.

In the following description, the direction indicated by arrow D is referred to as "axial direction D". Also, the direction indicated by the arrowhead D1 of the arrow D is referred to as the "front end direction", and the direction indicated by the arrowhead D2 is referred to as the "rear end direction". The direction indicated by the arrowhead F1 of the arrow F is referred to as the "forward rotation direction", and the direction indicated by the arrowhead F2 is referred to as the "reverse rotation direction". Further, the direction away from the central axis X1 along the radial direction of the outer shaft 504 (the direction from the central axis X1 toward the outer peripheral surface) is referred to as the "outer radial direction".

The outer shaft 504 is movable in both the front end direction D1 and the rear end direction D2. In addition, the outer shaft 504 is rotatable in both the forward rotation direction F1 and the reverse rotation direction F2.
As shown in FIGS. 14 and 15A, the outer shaft 504 is formed with a through hole 513 . The through hole 513 is formed from the outer peripheral surface of the outer shaft 504 toward the inner peripheral surface. The through hole 513 constitutes a first engaging portion (hereinafter referred to as “first engaging portion 513”), which will be described later.

Outer shaft 504 has a small diameter portion 507 and a large diameter portion 508 .
The small diameter portion 507 is provided on the front end direction D1 side of the outer shaft 504 . The small diameter portion 507 is inserted through the block 531 . A pin 518 is inserted near the end of the small diameter portion 507 in the front end direction D1. The pin 518 prevents the small diameter portion 507 from slipping out of the block 531 when the outer shaft 504 moves in the rear end direction D2. As shown in FIG. 13, the block 531 is arranged inside a cover 550 which will be described later. A fixed plate 542 is fixed to the block 531 . The fixing plate 542 is attached to the second side wall 88R of the column frame 88 with a fixture (bolt) 543. As shown in FIG.

Large diameter portion 508 includes a first large diameter portion 509 and a second large diameter portion 510 . The first large diameter portion 509 has a larger outer diameter than the second large diameter portion 510 . The first large diameter portion 509 is provided on the rear end direction D2 side of the outer shaft 504 . The first large-diameter portion 509 is a portion that is gripped by an operator's hand when operating the outer shaft 504 . The second large diameter portion 510 is provided between the first large diameter portion 509 and the small diameter portion 507 . The large-diameter portion 508 (the first large-diameter portion 509 and the second large-diameter portion 510 ) is arranged outside the block 531 and the cover 550 .

As shown in FIGS. 14 and 15A, at the end of the large-diameter portion 508 on the rear end direction D2 side, there is formed a recessed portion 514 that is cylindrically recessed toward the front end direction D1. The recessed portion 514 is connected to the through hole 513 . Recessed portion 514 includes a first recessed portion 515 and a second recessed portion 516 . The first recessed portion 515 has a larger inner diameter than the second recessed portion 516 and is provided on the rear end direction D2 side of the second recessed portion 516 .

The switching mechanism 512 is a mechanism capable of switching between a first state that permits movement of the outer shaft (moving member) 504 and a second state that prevents movement of the outer shaft (moving member) 504 .
As shown in FIGS. 14 and 15A, the switching mechanism 512 has an inner shaft 521 inserted into the outer shaft 504. As shown in FIGS. The inner shaft 521 is movable along the axial direction D of the outer shaft 504 . The inner shaft 521 rotates together with the outer shaft 504 when the outer shaft 504 rotates around the central axis X1. That is, the inner shaft 521 and the outer shaft 504 rotate together.

As shown in FIGS. 14 and 15A, the inner shaft 521 has a shaft portion 522 and a head portion 523 . Axial portion 522 is inserted into outer shaft 504 . The head 523 is provided at the end of the outer shaft 504 on the rear end direction D2 side. The outer diameter of the head portion 523 is larger than the outer diameter of the shaft portion 522 . Head 523 is arranged in first recess 515 of recess 514 of outer shaft 504 . The outer diameter of head 523 is smaller than the outer diameter of first recessed portion 515 and larger than the outer diameter of second recessed portion 516 . A spring 519 is arranged in the recessed portion 514 .

The spring 519 pushes the head portion 523 of the inner shaft 521 toward the rear end direction D2 by means of a biasing force (elastic repulsive force) in an extending direction. As a result, the inner shaft 521 is biased toward the rear end direction D2. Therefore, when the operator does not operate the adjusting device 511, the inner shaft 521 is positioned on the rear end direction D2 side with respect to the outer shaft 504 (hereinafter referred to as "retracted state") (see FIG. 15A). ).

When the operator pushes the head portion 523 of the inner shaft 521 toward the front end, the spring 519 shortens and the inner shaft 521 moves toward the front end. As a result, as shown in FIG. 17, the inner shaft 521 is positioned on the front end direction D1 side with respect to the outer shaft 504 (hereinafter referred to as "advance state"). In this forward state, the head portion 523 of the inner shaft 521 abuts or approaches the end surface 515a of the first recessed portion 515 on the front end direction side.

The switching mechanism 512 can switch between the first state and the second state as the inner shaft 521 moves. Specifically, as the inner shaft 521 moves from the retracted state to the advanced state, the switching mechanism 512 changes from the second state that prevents the movement of the outer shaft (moving member) 504 to the first state that allows the movement of the outer shaft 504 . switch to state. On the other hand, the switching mechanism 512 switches from the first state allowing the movement of the outer shaft 504 to the second state blocking the movement of the outer shaft 504 as the inner shaft 521 moves from the forward state to the backward state. . The operation of this switching mechanism 512 will be described later in more detail.

As shown in FIGS. 14, 15A, and 15B, the inner shaft 521 has a first recess 524 and a second recess 525 formed side by side in the axial direction D. As shown in FIGS. The second recess 525 is recessed deeper than the first recess 524 . The second recess 525 is arranged closer to the rear end direction D2 than the first recess 524 is. The second recessed portion 525 has a deepest portion 526 which is the deepest recess and an inclined portion 527 which is inclined so as to gradually become deeper toward the deepest portion 526 . The inclined portions 527 are provided on the front end direction D1 side and the rear end direction D2 side of the deepest portion 526, respectively. The inclined portion 527 provided on the front end direction D1 side is continuous with the first concave portion 524 .

As shown in FIGS. 15A and 15B, the first recessed portion 524 and the second recessed portion 525 are arranged in the axial direction D so as to overlap the through hole (first engagement portion) 513 formed in the outer shaft 504. It is When the inner shaft 521 is in the retracted state, the first concave portion 524 overlaps the through hole (first engaging portion) 513 in the axial direction D (see FIGS. 15A and 15B). When the inner shaft 521 is in the advanced state, the second concave portion 525 overlaps the through hole (first engaging portion) 513 in the axial direction D (see FIG. 17).

As shown in FIGS. 14-16, the switching mechanism 512 has a wire rod 536 spirally wound around the outer shaft 504 . The wire 536 constitutes a coil spring 537 by being spirally wound at a constant pitch. A coil spring 537 is housed inside the block 531 .
As shown in FIG. 15B, block 531 has receiving hole 532 . The accommodation hole 532 penetrates the block 531 in the axial direction D. As shown in FIG. The accommodation hole 532 has a first accommodation portion 533 and a second accommodation portion 534 . The first accommodation portion 533 is provided on the front end direction D1 side. The second accommodation portion 534 is provided on the rear end direction D2 side. The first accommodating portion 533 has a larger inner diameter and a longer length in the axial direction D than the second accommodating portion 534 .

A stop plate 539 is fixed to the end of the block 531 on the front end direction side by a fixture (bolt) 540 . The coil spring 537 is housed in the first housing portion 533 . One end side of the coil spring 537 is fixed to the end portion of the first accommodating portion 533 on the rear end direction D2 side. The other end side of the coil spring 537 is fixed to a stop plate 539 . As a result, the coil spring 537 is fixed within the large-diameter portion 508 and cannot move, rotate, or expand or contract. A cylindrical bush 535 is accommodated in the second accommodation portion 534 . The bush 535 is in contact with the inner peripheral surface of the second accommodating portion 534 and the outer peripheral surface of the outer shaft 504 .

A gap 538 between the wire rods 536 appearing at predetermined intervals along the axial direction D of the coil spring 537 constitutes a second engaging portion (hereinafter referred to as "second engaging portion 538") to be described later. Since the coil spring 537 cannot move, rotate, or expand or contract, the interval (pitch) between the wire rods 536 along the axial direction D is constant. Therefore, the second engaging portions 538 formed by the gaps 538 between the wire rods 536 are immovably arranged at predetermined intervals along the axial direction D outside the outer shaft 504 (see FIG. 15B).

As shown in FIGS. 15A and 15B, a through-hole (first engagement portion) 513 formed in the outer shaft 504 and a first recess 524 and a second recess 525 formed in the inner shaft 521 extend in the axial direction D. , is arranged at a position overlapping with the coil spring 537 . As a result, the through hole (first engaging portion) 513, the first concave portion 524, and the second concave portion 525 form a second engaging portion formed by a gap 538 between the wire rods 536 forming the coil spring 537 in the axial direction D. It can overlap with section 538 .

As shown in FIGS. 14, 15A, and 15B, the switching mechanism 512 has an engaging member 541 that can be engaged with the first engaging portion (through hole) 513 and the second engaging portion (gap) 538. ing. The engaging member 541 is composed of a sphere (hereinafter referred to as "sphere 541").
The inner diameter of the through hole 513 forming the first engaging portion 513 is set equal to or greater than the outer diameter of the spherical body 541 forming the engaging member 541 . Therefore, as shown in FIG. 15B, the sphere 541 can fit into the through-hole 513 . The engaging member (sphere) 541 is engaged with the first engaging portion (through hole) 513 by fitting the ball 541 into the through hole 513 .

Further, the thickness of the small diameter portion 507 of the outer shaft 504 in which the through hole 513 is formed is smaller than the diameter of the sphere 541 . Therefore, as shown in FIG. 15B, in a state where the sphere 541 is fitted in the through hole 513 (a state in which the engaging member (sphere) 541 is engaged with the first engaging portion (through hole) 513), the A part protrudes from the through hole 513 .
A gap 538 between the wires 536 forming the second engaging portion 538 is set smaller than the outer diameter of the sphere 541 forming the engaging member 541 . As shown in FIG. 15B and the like, the entire sphere 541 cannot fit into the gap 538, but a part of the surface side can fit into the gap 538. As shown in FIG. The engaging member (sphere) 541 is engaged with the second engaging portion (gap) 538 by fitting a part of the sphere 541 into the gap 538 .

The depths of the first recess 524 and the second recess 525 formed in the inner shaft 521 are smaller than the outer diameter of the sphere 541 . Accordingly, when the ball 541 is fitted into the first recess 524, the ball 541 projects radially outward from the first recess 524 (see FIGS. 15A and 15B), and when it is fitted into the second recess 525, the ball 541 projects radially outward from the second recess 525. (See FIG. 17). A portion of the sphere 541 protruding from the first recess 524 or the second recess 525 can be fitted into the through hole 513 forming the first engaging portion 513 .

Since the second recessed portion 525 is recessed deeper than the first recessed portion 524, the amount of projection of the ball 541 when fitted into the first recessed portion 524 is larger than the amount of projection when fitted into the second recessed portion 525. . Therefore, as shown in FIGS. 15A and 15B , when the ball 541 is fitted into the first recess 524 , the portion protruding from the first recess 524 is fitted into the first engaging portion (through hole) 513 and It also fits into the second engaging portion (gap) 538 . This state is the second state in which the switching mechanism 512 blocks the movement of the moving member 504 . On the other hand, as shown in FIG. 17, when the sphere 541 is fitted into the second recess 525, the portion protruding from the second recess 525 fits into the first engaging portion (through hole) 513, but the second It does not fit into the engaging portion (gap) 538 (disengages from the second engaging portion 538). This state is the first state in which the switching mechanism 512 allows the movement of the moving member 504 .

In other words, the ball 541 is engaged with the first engaging portion 513 and disengaged from the second engaging portion 538 in the first state (see FIG. 17), and in the second state, the first engaging portion 513 and the second engaging portion 538 are separated from each other. It is engaged with the engaging portion 538 (see FIGS. 15A and 15B). Also, the ball 541 fits into the second recess 525 in the first state, and fits into the first recess 524 in the second state.
Hereinafter, while describing the operation of the switching mechanism 512, the adjusting method by the adjusting device 511 will be described.

8 (see symbol P1) and FIG. 13 show the state where the swing member 501 is at the first position. In this state, the brake pedal 111 is at the initial stroke position. This state is a state in which the stroke of the brake pedal 111 is not adjusted by the adjusting device 511 (unadjusted state). At this time, the front end portion of the outer shaft (moving member) 504 is in contact with or close to the contact portion 503 of the swing member 501 . 15A and 15B, the ball (engagement member) 541 is fitted into the first recess 524 of the inner shaft 521, and the through hole (first engagement portion) 513 of the outer shaft 504 and the It is engaged with the second engaging portion (gap) 538 . Therefore, the outer shaft 504 cannot move in the axial direction D. That is, the switching mechanism 512 is in the second state in which movement of the outer shaft (moving member) 504 is blocked.

When the head portion 523 of the inner shaft 521 is pushed toward the front end direction D1 from the state (unadjusted state) shown in FIGS. 15A and 15B (see arrow G in FIG. 17), the inner shaft 521 moves toward the front end direction D1. do. As a result, the sphere (engagement member) 541 is released from the first recess 524 and fitted into the second recess 525 , and the sphere (engagement member) 541 is released from the second engagement portion (gap) 538 . As a result, the outer shaft 504 can move in the axial direction D. That is, the switching mechanism 512 switches to the first state that allows movement of the outer shaft (moving member) 504 .

Next, when the outer shaft 504 is moved in the front end direction D1, the sphere 541 moves together with the outer shaft 504 in the front end direction. As a result, as shown in FIG. 18, the ball 541 disengages from the second recess 525 and fits into the first recess 524, and is adjacent to the second engaging portion 538 engaged in the unadjusted state. It is engaged with another second engaging portion 538 . That is, the ball 541 moves in the front end direction D1 by one pitch of the coil spring 537, and the outer shaft 504 also moves in the front end direction D1 by one pitch. At this time, the outer shaft 504 cannot move in the axial direction D because the ball 541 is engaged with the first engaging portion 513 and the second engaging portion 538 . That is, the switching mechanism 512 is again in the second state in which movement of the outer shaft (moving member) 504 is blocked.

In this way, when the outer shaft 504 moves in the front end direction D1, the front end portion 504a of the outer shaft 504 moves in contact with the contact portion 503 of the rocking member 501 (see FIG. 19). As a result, the swinging member 501 is pushed by the front end portion 504a of the outer shaft 504 and swings from the position indicated by the solid line to the position indicated by the phantom line. As a result, the first position P1 of the swing member 501 is changed from the position indicated by the solid line to the position indicated by the phantom line. The direction in which the first position P1 is changed is the direction toward the second position P2. The initial position of the stroke of the brake pedal 111 is changed along with the change of the first position P1. Also, this changed initial position is fixed by engaging the ball 541 with the second engaging portion 538 .

In the above description, the case where the outer shaft 504 is moved toward the front end by one pitch of the coil spring 537 has been described. The operation described above may be repeated two or more times.
When moving the outer shaft 504 in the rear end direction D2, the inner shaft 521 is moved in the front end direction D1 from the state shown in FIG. It moves in the rear end direction D2 together with the sphere 541 . At this time, the inner shaft 521 is pushed in the rear end direction D2 by the ball 541 inserted into the second recess 525, so that the inner shaft 521 moves together with the outer shaft 504 to the state shown in FIG. After that, the inner shaft 521 receives the biasing force of the spring 519 and moves in the rear end direction D2, so that the ball 541 moves from the second recess 525 to the first recess 524 . As a result, the ball 541 is pushed radially outward and engages with the second engaging portion 538, resulting in the state shown in FIGS. 15A and 15B.

When the outer shaft 504 moves in the rear end direction D2, the swinging member 501 swings back from the virtual line position in FIG. 19 to the solid line position by the biasing force of the return spring 131. As a result, the first position P1 of the swing member 501 is changed. The direction in which the first position P1 is changed is the direction away from the second position P2. The initial position of the stroke of the brake pedal 111 is changed along with the change of the first position P1. Also, this changed initial position is fixed by engaging the ball 541 with the second engaging portion 538 .

According to the above method, the first position of the rocking member 501 can be changed and the initial position of the stroke of the brake pedal 111 can be changed by moving the outer shaft 504 in the front end direction or the rear end direction.
However, with the above method, the outer shaft 504 can only be moved by a distance of one pitch unit of the coil spring 537 . Therefore, it may be difficult to finely adjust the initial position of the stroke of the brake pedal 111 to the operator's desired position. A method for finely adjusting the initial position of the stroke of the brake pedal 111 will be described below.

15A, 15B, and 16 (unadjusted state), the initial position of the stroke of the brake pedal 111 is finely adjusted, as indicated by an arrow F1 in FIG. Rotate in the forward rotation direction F1. At this time, since the inner shaft 521 rotates together with the outer shaft 504 , the spherical body 541 is kept inserted in the first concave portion 524 and engaged with the second engaging portion 538 , and the outer shaft 504 is rotated. As it rotates, it spirally moves along the wire 536 (see arrow H). As a result, the outer shaft 504 moves together with the ball 541 in the front end direction D1. 20, the outer shaft 504 is moved in the front end direction D1 by moving the outer shaft 504 by a quarter pitch of the coil spring 537 from the state shown in FIGS. 15A, 15B, and 16 (unadjusted state). state. If it is desired to move the outer shaft 504 longer than 1/4 pitch, the outer shaft 504 should be further rotated in the forward rotation direction F1.

In order to move the outer shaft 504 in the rear end direction D2, the outer shaft 504 should be rotated in the reverse rotation direction F2 (see FIG. 15) around the central axis X1.
According to the above method, by rotating the outer shaft 504 around the central axis X1, the outer shaft 504 can be moved in the front end direction D1 or the rear end direction D2. By changing the position, the initial position of the stroke of the brake pedal 111 can be changed. According to this method, the outer shaft 504 can be moved by a distance smaller than one pitch of the coil spring 537, so that the initial position of the stroke of the brake pedal 111 can be finely adjusted to a desired position. Become.

As described above, the adjustment device 511 can change the first position P1 (see FIG. 8) of the swing member 501 by moving the outer shaft 504 .
When the outer shaft 504 has not moved (located on the rearmost direction D2 side) and the first position P1 of the rocking member 501 has not been changed (adjusted by the adjusting device 511), the brake pedal 111 is not depressed (the brake pedal 111 is at the initial stroke position), the rotary spool of the valve body 338A of the inching valve 338 is at the first position 3381, and the inching valve 338 is in the off state (closed state). )It is in.

When the outer shaft 504 is moved in the front end direction D1 by the adjusting device 511 from the OFF state (when the first position P1 of the rocking member 501 is moved to the second position P2 side), the brake pedal 111 is depressed. In the empty state, the rotary spool of valve body 338A is located between first position 3381 and second position 3382. As shown in FIG. That is, when the brake pedal 111 is not depressed, the inching valve 338 is slightly opened.

By adjusting the amount of movement of the outer shaft 504 (the amount of movement in the front end direction D1 from the position where it first contacts the contact portion 503), the movement of the inching valve 338 when the brake pedal 111 is not depressed is controlled. The valve opening can be adjusted steplessly (within any range). As a result, the speed of the work implement 1 (the output of the travel device 17) can be adjusted steplessly when the brake pedal 111 is not depressed. Further, the output of the travel device 17 (the speed of the work implement 1) can be adjusted steplessly without operating the accelerator pedal 500. FIG.

As shown in FIGS. 4 and 5 , the adjustment device 511 is attached to the steering column 87 that supports the steering wheel 15 . Specifically, the adjustment device 511 is attached to the side surface of the steering column 87 . The side surface of the steering column 87 to which the adjusting device 511 is attached is the side surface (right side surface) opposite to the brake pedal 111 side. Specifically, the adjustment device 511 is attached to the outer surface of the second side wall 88R of the column frame 88 (the surface on the outer side of the aircraft body).

Further, the adjusting device 511 is arranged at a position overlapping the steering wheel 15 in the longitudinal direction K1 and the body width direction K2. As shown in FIG. 5 , the adjustment device 511 is arranged on the left side of the right end of the steering column 87 (on the inside of the vehicle body). Further, as shown in FIG. 5, the adjusting device 511 is arranged between the accelerator pedal 500 and the steering column 87 in the machine width direction K2.

As shown in FIG. 4, the adjustment device 511 is arranged at a position overlapping the accelerator pedal 500 in the front-rear direction K1. In addition, the adjusting device 511 is arranged forward of the rear end portion of the steering column 87 in the front-rear direction K1, and does not protrude rearward from the rear end portion of the steering column 87 .
Further, as shown in FIG. 4, the adjustment device 511 is arranged at a height overlapping the seat portion 13a of the driver's seat 13 in the vertical direction. Specifically, the rear end (upper end) of the outer shaft 504 of the adjustment device 511 and the rear end (upper end) of the inner shaft 521 overlap the seat portion 13 a of the driver's seat 13 . It is placed at a height that In addition, the rear end (upper end) of the outer shaft 504 of the adjustment device 511 and the rear end (upper end) of the inner shaft 521 are located higher than the upper surface (seating surface) of the seat portion 13a. placed in a low position.

The adjusting device 511 has a cover 550 as shown in FIGS. The cover 550 is attached to the second side wall 88R of the column frame 88 with fasteners (bolts) 557. As shown in FIG. The cover 550 covers the outer peripheral side of the outer shaft 504 . As shown in FIG. 13 , the outer shaft 504 is arranged inside the cover 550 on the front side and outside the cover 550 on the rear side. The outer shaft 504 is inclined with respect to the vertical direction so as to shift from the rear side (one side) to the front side (the other side) as it goes downward.

As shown in FIGS. 13, 21, 22, etc., the cover 550 includes an upper plate (first plate) 551, a rear plate (second plate) 552, a lower plate (third plate) 553, a front plate 554, and a right side plate. It consists of a plate 555 . As shown in FIG. 23, the cover 550 is open on the left side. As shown in FIG. 22, the open left side of the cover 550 is covered with the second side wall 88R and the right side wall 89R of the column cover 89. As shown in FIG. As a result, the periphery of the outer shaft 504 on the front end side is covered with the cover 550, the second side wall 88R and the right side wall 89R. The outer shaft 504 is relatively movable with respect to the cover 550 in the axial direction D of the outer shaft 504 (see FIG. 20).

The upper plate 551 is inclined downward from the front side (the other side) toward the rear side (the one side). As shown in FIGS. 15B, 22 and 23, the upper plate 551 is formed with an opening 551a through which the outer shaft 504 is inserted. As shown in FIG. 22, the opening 551a is formed by cutting the upper plate 551 in a U shape from the left side (right side wall 89R side) toward the right side.

The rear plate 552 is connected to the upper plate 551 on the rear side (one side) of the outer shaft 504 . The rear plate 552 is slanted so as to move downward from the rear side (one side) to the front side (the other side). The lower plate 553 is arranged to be connected to the lower end of the rear plate 552 . The lower plate 553 extends forward (the other side) from the lower end of the rear plate 552 and faces the upper plate 551 . In the case of this embodiment, the lower plate 553 is arranged horizontally, but it may be inclined downward from the front side (the other side) toward the rear side (the one side).

The front plate 554 includes a first front plate 554a and a second front plate 554b. The right side plate 555 includes a first right side plate 555a and a second right side plate 555b. The first front plate 554a is arranged behind the second front plate 554b. The first right side plate 555a is arranged behind the second right side plate 555b. The first right side plate 555 a connects the rear plate 552 , the upper plate 551 and the lower plate 553 . The first front plate 554 a connects the first right side plate 555 a , the upper plate 551 and the lower plate 553 . The second right side plate 555b connects the second front plate 554b, the upper plate 551 and the lower plate 553 together. The second front plate 554 b connects the second right side plate 555 b , the upper plate 551 and the lower plate 553 .

The upper plate 551 and the lower plate 553 are provided with mounting pieces 556 that are attached in contact with the second side wall 88R. A fitting (bolt) 557 is inserted through the fitting piece 556, and the fitting 557 is attached to the second side wall 88R. A circular opening 558 (see FIG. 21) is formed in the second right side plate 555b. Exposed.

As shown in FIGS. 13, 15A, 15B, and 21-23, a sealing material 560 is attached to the cover 550. As shown in FIGS. The sealing material 560 is made of an elastic material such as rubber. The sealing material 560 seals between the outer peripheral surface of the outer shaft 504 and the edge of the opening 551a. As shown in FIG. 15B and the like, the sealing member 560 has an inner edge portion 561 that is in close contact with the outer peripheral surface of the outer shaft 504 due to elastic deformation, and an outer edge portion 562 that is attached to the opening edge of the opening portion 551a.

As shown in FIG. 24, the sealing material 560 is formed in a thin plate shape and has a circular hole 563 . The sealing material 560 has a top surface 564 , a bottom surface 565 and side surfaces 566 . The upper surface 564 and the lower surface 565 are flat surfaces and are provided parallel to each other. A circular hole 563 penetrates the sealing material 560 from an upper surface 564 to a lower surface 565 .
As shown in FIG. 24, the side surface 566 has a first portion 567, a second portion 568, a third portion 569 and a fourth portion 570. As shown in FIG. The first portion 567 and the second portion 568 linearly extend parallel to each other. The third portion 569 extends to connect one end side of the first portion 567 and one end side of the second portion 568 . The third portion 569 is formed in an arc shape extending concentrically with the circular hole 563 . The fourth portion 570 extends linearly to connect the other end side of the first portion 567 and the other end side of the second portion 568 . The distance between the fourth portion 570 and the center of the circular hole 563 is longer than the distance between the other portions (the first portion 567, the second portion 568, and the third portion 569) and the center of the circular hole 563.

An inner peripheral edge of the circular hole 563 constitutes an inner edge portion 561 of the sealing material 560 . As shown in FIG. 15B , the inner edge portion 561 of the sealing material 560 is formed into a curved surface that protrudes toward the outer peripheral surface of the outer shaft 504 . The curved inner edge portion 561 is in close contact with the outer peripheral surface of the outer shaft 504 in a state where the bulging end (top of the bulging) is compressed by elastic deformation. This prevents water from entering through the gap between the inner edge portion 561 of the seal member 560 and the outer peripheral surface of the outer shaft 504 .

In addition, the inner edge portion 561 of the seal member 560 is in contact with the outer peripheral surface of the outer shaft 504 over the entire circumferential direction. Therefore, it is possible to prevent water from entering through the gap between the inner edge portion 561 of the seal member 560 and the outer peripheral surface of the outer shaft 504 over the entire circumferential direction of the outer peripheral surface of the outer shaft 504 .
The side surface 566 constitutes the outer edge of the sealing material 560 . As shown in FIG. 24, a groove 571 is formed in the side surface 566 . The groove 571 has an upper wall 572 , a lower wall 573 and an inner wall 574 . The concave groove 571 is formed over the first portion 567 , the second portion 568 and the third portion 569 . A groove 571 is not formed in the fourth portion 570 . As a result, the fourth portion 570 is formed flat.

As shown in FIG. 15B, the outer edge portion 562 of the sealing member 560 is fitted with the opening edge (inner edge) of the opening 551a through which the outer shaft 504 is inserted. In a state in which the opening edge of the opening 551a is fitted into the outer edge 562 of the sealing material 560, the upper wall 572 of the groove 571 contacts the upper surface of the upper plate 551 of the cover 550, and the lower wall 573 of the groove 571 contacts the cover. 550 is in contact with the lower surface of the upper plate 551 . The groove 571 sandwiches the upper plate 551 and the lower plate 553 by elastic force. Thereby, the sealing material 560 is attached to the upper plate 551 of the cover 550 .

As described above, the opening 551a is formed by cutting the upper plate 551 from left to right in a U shape (see FIG. 22). Therefore, the sealing material 560 can be easily attached to the upper plate 551 by fitting the groove 571 along the opening edge of the opening 551a from the left side of the upper plate 551 .
As shown in FIG. 22, in a state in which the sealing material 560 is attached to the upper plate 551 of the cover 550, the first portion 567 and the second portion 568 extend in the body width direction K2. The third portion 569 has one end connected to the first portion 567 arranged on the front side, and the other end connected to the second portion 568 arranged on the rear side. The fourth portion 570 extends in the front-rear direction K1 and contacts the right side wall 89R of the column cover 89. As shown in FIG. As shown in FIG. 13 , the first portion 567 is positioned forward of the front end of the upper end surface of the block 531 . The second portion 568 is located behind the rear end of the upper end surface of the block 531 .

As shown in FIG. 23, the lower plate 553 is formed with drain holes 575 for discharging water that has entered the interior of the cover 550 . Water adhering to the upper plate 551 of the cover 550 may enter the groove 571 of the sealing material 560 . In this case, since the upper plate 551 is inclined, the water that has entered the groove 571 flows from the front to the rear along the groove 571 (see arrow J1). Specifically, the water entering from the groove 571 formed in the first portion 567 flows through the groove 571 formed in the third portion 569 to the groove 571 formed in the second portion 568. After that, it flows along the lower surface of the upper plate 551, reaches the rear plate 552 as indicated by arrow J2 (see arrow J2), flows down along the rear plate 552, and reaches the upper surface of the lower plate 553 (see arrow J3). ), and discharged to the outside of the cover 550 through the drain hole 575 (see arrow J4).

In this way, the recessed groove 571 functions as a water guiding groove for guiding water, thereby bypassing the outer shaft 504 and detouring the water from the front side (the other side) of the outer shaft 504 to the rear side (one side). The detoured water flows down inside the cover 550 through the front side (the other side) of the outer shaft 504 and then is discharged to the outside of the cover 550 through the drain hole 575 . As a result, even when water enters the inside of the cover 550, it can be prevented from entering through the gap between the outer shaft 504 and the block 531, and water can be prevented from accumulating inside the cover 550.例文帳に追加

Further, although not shown, as a measure to prevent water from entering, a configuration may be employed in which the upper portions (rear end direction side) of the outer shaft 504 and the inner shaft 521 are covered with a shaft cover made of an elastic material such as rubber. good. In this case, the shaft cover can be configured to cover at least the first large diameter portion 509 of the outer shaft 504 and the head portion 523 of the inner shaft 521, for example.

As described above, the working machine 1 of the present embodiment includes the machine body 2, the traveling device 17 that supports the machine body 2 so as to be able to travel, the hydraulic drive device 353 that hydraulically drives the traveling device 17, and the braking device for the traveling device 17. A pedal (brake pedal) 111 for operation, an inching valve 338 that changes the flow rate of hydraulic oil supplied to the hydraulic drive device 353 according to the operation of the pedal 111, and an adjustment device that adjusts the stroke of the operation of the pedal 111. 511, the adjusting device 511 swings in conjunction with the operation of the pedal 111, and the swinging member 501 is at the first position P1 when the pedal 111 is at the initial position of the stroke; A moving member 504 that can move in contact with and changes the first position P1 by the movement, a first state that allows the movement of the moving member 504, and a second state that prevents the movement of the moving member 504. and a switching mechanism 512 capable of switching between .

According to this configuration, in the working machine 1 having the inching valve 338 that operates according to the operation of the pedal 111, by moving the moving member 504, the initial position of the operation stroke of the pedal 111 can be adjusted. By blocking the movement of the moving member 504 by the switching mechanism 512, the adjusted initial position can be fixed. Therefore, the pedal operation stroke (inching region) for operating the inching valve 338 can be easily adjusted (steplessly) within an arbitrary range and fixed. Further, the speed of the work implement 1 (the output of the traveling device 17) can be adjusted steplessly when the pedal 111 is not operated (the pedal 111 is at the initial position of the stroke).

The moving member 504 is composed of a cylindrical outer shaft 504, and the switching mechanism 512 has an inner shaft 521 inserted into the outer shaft 504 and movable along the axial direction of the outer shaft 504. Therefore, it is possible to easily switch between the first state and the second state as the inner shaft 521 moves.
According to this configuration, it is possible to switch between the first state and the second state by moving the inner shaft 521 along the axial direction of the outer shaft 504, so the switching mechanism 512 can be configured simply. In addition, the operability of the switching mechanism 512 is excellent.

The switching mechanism 512 includes a first engaging portion 513 formed on the outer shaft 504 and a second engaging portion 538 immovably arranged on the outer peripheral side of the outer shaft 504 at predetermined intervals along the axial direction. , the engagement is engaged with the first engaging portion 513 and disengaged from the second engaging portion 538 in the first state, and is engaged with the first engaging portion 513 and the second engaging portion 538 in the second state. It has a joint member 541 and.

According to this configuration, by moving the engaging member 541 in the axial direction of the outer shaft 504, the engaging member 541 switches between the engaged state and the disengaged state with respect to the second engaging portion 538. A first state and a second state can be switched.
Further, the switching mechanism 512 has a wire rod 536 spirally wound around the outer shaft 504, and the second engaging portion 538 is formed from a gap between the wire rods 536 appearing at predetermined intervals along the axial direction. It is configured.

According to this configuration, the second engaging portion 538 can be configured by a component such as the coil spring 537 in which the wire rod 536 is spirally wound. Can be configured.
The first engaging portion 513 is composed of a through hole 513 formed in the outer shaft 504, and the engaging member 541 is composed of a sphere 541 that can be engaged with the through hole 513 and the gap 538. The sphere 541 is , engages the through hole 513 and disengages from the gap 538 in the first state, and engages the through hole 513 and the gap 538 in the second state.

According to this configuration, the engaging member 541 composed of the sphere 541 is attached to the first engaging portion 513 composed of the through hole 513 and the second engaging portion 538 composed of the gap between the wires 536. Therefore, it is possible to easily and reliably perform the operation of engaging or disengaging.
In addition, the inner shaft 521 has a first recessed portion 524 and a second recessed portion 525 formed side by side in the axial direction. , fits into the first recess 524 in the first state, and fits into the second recess 525 in the second state.

According to this configuration, by moving the inner shaft 521 in the axial direction of the outer shaft 504, the first state in which the ball 541 is fitted in the first recess 524 and the second state in which the ball 541 is fitted in the second recess 525 can be easily changed. and can be reliably switched.
In addition, the outer shaft 504 is rotatable around the central axis X1. As the outer shaft 504 rotates, the sphere 541 spirally moves along the wire rod 536. As the sphere 541 moves, the outer A shaft 504 moves along the axial direction.

According to this configuration, by rotating the outer shaft 504 around the central axis X1, the outer shaft 504 moves in the axial direction. can. As a result, the first position P1 of the swing member 501 can be finely adjusted, and the initial position of the stroke of the brake pedal 111 can be finely adjusted to a desired position by the operator.

The work machine 1 also includes a steering wheel 15 that operates the travel device 17 and a steering column 87 that supports the steering wheel 15 , and the adjusting device 511 is attached to the side surface of the steering column 87 .
According to this configuration, the adjusting device 511 is arranged at a position where an operator sitting in the driver's seat 13 can easily reach out and operate it. Therefore, the operability of the adjusting device 511 is excellent. Also, the adjustment device 511 does not block the operator's field of view.

Further, the adjusting device 511 is arranged at a position overlapping the steering wheel 15 in the longitudinal direction K1 and the body width direction K2.
According to this configuration, an operator seated in the driver's seat 13 can easily operate the adjusting device 511, and the adjusting device 511 does not interfere with the operator's leg extension.

Further, the shaft seal structure of this embodiment includes a shaft (outer shaft) 504, a cover 550 having an opening 551a through which the shaft 504 is inserted, and between the outer peripheral surface of the shaft 504 and the opening edge of the opening 551a. The shaft 504 is relatively movable in the axial direction D of the shaft 504 with respect to the cover 550, and the seal member 560 is elastically deformed on the outer peripheral surface of the shaft 504. It has an inner edge portion 561 that is in close contact with an outer edge portion 562 that is attached to the opening edge of the opening portion 551a. , a groove 571 into which the opening edge is fitted is formed.

According to this configuration, the curved inner edge portion 561 of the sealing material 560 can exhibit excellent sealing performance. In addition, by fitting the opening edge of the opening 551a into the recessed groove 571 formed in the outer edge portion 562 of the sealing material 560, the sealing material 560 can be easily assembled.
In addition, the inner edge portion 561 is in contact with the outer peripheral surface of the shaft 504 over the entire circumferential direction.

According to this configuration, the sealing material 560 can exhibit excellent sealing performance over the entire circumferential direction of the outer peripheral surface of the shaft 504 .
Further, the shaft 504 is disposed inclined with respect to the vertical direction so as to shift from one side to the other side as it goes downward. It has a first plate 551 that slopes down toward one side.

According to this configuration, even if water enters the groove 571 of the sealing material 560 , the water flows along the groove 571 from the other side of the shaft 504 to the one side due to the inclination of the first plate 551 . can be diverted. Therefore, it is possible to prevent water that has entered the groove 571 of the sealing material 560 from adhering to the shaft 504 .
Further, the cover 550 has a second plate 552 connected to the first plate 551 on the one side of the shaft 504, and the second plate 552 moves downward from the one side to the other side. It is arranged at an angle so that

According to this configuration, the water flowing from the other side of the shaft 504 along the slope of the first plate 551 is guided to one side of the shaft 504 and then flows down along the slope of the second plate 552. Adhesion of water to the shaft 504 can be more reliably prevented.
The cover 550 also has a third plate 553 arranged to be connected to the lower end portion of the second plate 552 , and a drain hole 575 is formed in the third plate 553 .

According to this configuration, the water that has flowed down along the second plate 552 can be discharged to the outside of the cover 550 through the water drain hole 575 of the third plate 553, thereby preventing water from accumulating inside the cover 550. can.
The work machine 1 also includes a machine body 2, a traveling device 17 that supports the machine body 2 so that it can travel, a hydraulic drive device 353 that hydraulically drives the traveling device 17, and a pedal ( brake pedal) 111, an inching valve 338 that changes the flow rate of hydraulic oil supplied to the hydraulic drive device 353 according to the operation of the pedal 111, and a shaft ( an outer shaft 504, a cover 550 that covers the outer peripheral side of the shaft 504 and has a through hole through which the shaft 504 is inserted, and a sealing material 560 that seals between the outer peripheral surface of the shaft 504 and the opening edge of the opening 551a. , and the sealing material 560 has an inner edge portion 561 that is in close contact with the outer peripheral surface of the shaft 504 due to elastic deformation, and an outer edge portion 562 that is attached to the opening edge of the opening portion 551a. The outer edge portion 562 is formed with a concave groove 571 into which the opening edge is fitted.

According to this configuration, in the work machine 1 equipped with the inching valve 338 that operates according to the operation of the pedal 111, the shaft (outer shaft) 504 that adjusts the operation stroke of the pedal 111 and the through hole through which the shaft 504 is inserted. The seal structure between the cover 550 having the hole is a structure excellent in watertightness and assembling property of the seal material 560 . Specifically, the curved inner edge portion of the sealing material 560 can exhibit excellent sealing performance. In addition, by fitting the opening edge of the opening 551a into the recessed groove 571 formed on the outer edge of the sealing material 560, the sealing material 560 can be easily assembled.

Although one embodiment of the present invention has been described above, it should be considered that the embodiment disclosed this time is illustrative in all respects and is not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

1 working machine 2 machine body 17 travel device 111 pedal (brake pedal)
338 inching valve 353 hydraulic drive device 504 shaft (outer shaft)
550 Cover 551 First plate 551a Opening 552 Second plate 553 Third plate 560 Sealing material 561 Inner edge 562 Outer edge 571 Groove 575 Drain hole

Claims (6)

a shaft;
a cover having an opening through which the shaft is inserted;
a sealing material for sealing between the outer peripheral surface of the shaft and the edge of the opening;
with
the shaft is movable relative to the cover in the axial direction of the shaft;
The seal member has an inner edge that is in close contact with the outer peripheral surface of the shaft due to elastic deformation, and an outer edge that is attached to the opening edge of the opening,
The inner edge portion is formed in a curved surface shape bulging toward the outer peripheral surface,
A seal structure for a shaft, wherein the outer edge portion is formed with a groove into which the opening edge is fitted. 2. The shaft seal structure according to claim 1, wherein the inner edge portion is in contact with the outer peripheral surface over the entire circumferential direction. The shaft is arranged at an angle with respect to the vertical direction so as to shift from one side to the other side as it goes downward,
3. The shaft seal structure according to claim 1, wherein the cover has a first plate formed with the opening and inclined downward from the other side toward the one side. the cover has a second plate connected to the first plate on the one side of the shaft;
4. The shaft seal structure according to claim 3, wherein said second plate is disposed so as to be inclined so as to shift from said one side to said other side as it goes downward. The cover has a third plate connected to the lower end of the second plate,
5. The shaft seal structure according to claim 4, wherein the third plate is formed with a drain hole. Airframe and
a running device that supports the body so that it can run;
a hydraulic drive device that hydraulically drives the traveling device;
a pedal for performing a braking operation of the traveling device;
an inching valve that changes the flow rate of hydraulic oil supplied to the hydraulic drive device according to the operation of the pedal;
a shaft that moves axially to adjust the stroke of operation of the pedal;
a cover covering the outer peripheral side of the shaft and having an opening through which the shaft is inserted;
a sealing material for sealing between the outer peripheral surface of the shaft and the edge of the opening;
with
The seal member has an inner edge that is in close contact with the outer peripheral surface of the shaft due to elastic deformation, and an outer edge that is attached to the opening edge of the opening,
The inner edge portion is formed in a curved shape in which a cross section along the axial direction bulges toward the outer peripheral surface,
The working machine, wherein the outer edge portion is formed with a groove into which the opening edge is fitted.

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