JP2011080213A - Hydraulic device of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic device of a working vehicle capable of preventing a valve of the hydraulic device from being operated without fail even if an operation lever moves unexpectedly. <P>SOLUTION: In this hydraulic device of the working vehicle constituted to operate two valves 23, 24 independently by operating the operation lever in two directions, valve operation links 38, 39 for operating two valves 23, 24 independently are supported on support shafts provided on a pair of frame plates 40, 41 to swing freely, respectively, and a lock pin 55 is provided on the frame plates 40, 41 to form pin holes 51a, 52a in two valve operation links 38, 39. When two valves 23, 24 are at a neutral position, the lock pin 55 is inserted into the pin holes 51a, 52a through locking operation by using a locking operation implement 57, and the valve operation links 38, 39 are fixed to lock the valves 23, 24. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  In the present invention, two valves for two hydraulic devices are linked to a single operation lever, and the operation lever is configured to be operable in a first direction and a second direction intersecting the first direction, The present invention relates to a hydraulic device for a work vehicle configured to operate an operation lever in first and second directions to operate the valve separately.

  Patent Document 1 discloses a technique in which a single operation lever is operated in two directions to operate two valves separately in a first direction and a second direction. And in this patent document 1, in the linkage mechanism between two valves and an operation lever, a valve operation link connected to each valve is interposed, and the two valve operation links are sandwiched in the front-rear direction. The two bosses are supported in a cantilevered manner on the provided U-shaped frame plate in plan view, and the left and right support shafts for operating the operation lever in the front-rear direction are supported on one boss and the other boss The lock pin is slidably inserted in the horizontal direction in the left and right sides, and when the operation lever is in the neutral position, the operation lever is locked by operating the lock pin and inserting it into the boss formed integrally with the operation lever. Thus, a technique is shown in which the two valves are fixed in a neutral position.

JP 2008-245609 A (see FIGS. 7 to 11)

  In the thing of patent document 1, the operation lever is locked with respect to the direction which cross | intersects a lock pin, and the insertion direction to the boss | hub part of a lock pin by inserting a single lock pin into the boss | hub part integrally formed with the operation lever. Therefore, if the clearance between the lock pin and the boss that slidably supports the lock pin, and the clearance between the boss and the lock pin provided integrally with the operation lever are large, the operation lever is locked. In this state, when the operation lever is unexpectedly operated, the lock boss part easily slides in the axial direction of the lock pin, and one of the valve operation links may be operated to move the valve. .

  An object of the present invention is to provide a hydraulic device for a work vehicle that can reliably prevent the operation of a valve of the hydraulic device even if an operation lever moves unexpectedly.

[Configuration of the first invention]
The first invention is configured such that two valves for two hydraulic devices are linked to a single operation lever, and the operation lever can be operated in a first direction and a second direction intersecting the first direction, In a hydraulic device for a work vehicle configured to operate the operation lever in first and second directions to operate the valve separately,
A pair of frame plates provided with a valve operation link connected to each valve in a linkage mechanism between the two valves and the operation lever, and sandwiching the valve operation link, Holding the boss part that supports the spindle that operates in the first or second direction from both sides,
Each of the two valve operating links for operating the two valves separately is supported on a support shaft provided on the pair of frame plates, and a lock pin is provided on the frame plate. A pin hole is formed in the operation link, and when the two valves are in a neutral position, the valve operation link is fixed by inserting the lock pin into the pin hole by a lock operation using a lock operation tool. It is characterized by locking.
[Operation of the first invention]
According to the first aspect of the invention, the pair of frame plates provided with the valve operation link sandwiched between them hold the boss portions that support the support shaft of the operation lever from both sides so that the frame plates themselves are formed firmly and the boss portions are also formed. Even if the operation lever is operated in two directions, it is firmly held by the frame plate, so that the boss portion is not shaken, the support shaft can be reliably supported, and the operation of the operation lever in the predetermined first and second directions is deviated. It is possible to perform a light lever operation without any trouble.

  When two valves are in the neutral position, the two valve operation links are simultaneously fixed to lock the valve by inserting one lock pin into a plurality of pin holes formed in the two valve operation links. . In other words, the two valve operation links connected to the valve are directly locked by inserting one lock pin into the hole formed in the two valve operation links provided separately for operating the two valves. Therefore, even if there is play on the operation lever side, the two valves can be reliably locked in the neutral position.

Since the valve operation link, the boss portion supporting the operation lever support shaft, the lock pin, and the like are supported by a pair of frame plates, they can be produced and attached to the work vehicle as a single unit (assembly). .
[Effect of the first invention]
Since both the valve that operates by operating the operating lever in the first direction and the valve that operates by operating the operating lever in the second direction can be reliably locked in the neutral state, the operating lever is inadvertent Even if it is moved, the operation of the valve can be reliably prevented.

A pair of frames (valve operation links, bosses, lock pins, etc.) can be made into one unit (assembly), and productivity can be improved.
[Configuration of the second invention]
According to a second aspect of the invention, in the configuration of the first aspect of the invention, the lock pin is supported by one frame plate of the pair of frame plates in a state in which the valve is unlocked, and a valve operation link for locking the valve. In a state where is fixed, it is configured to be supported by both of the pair of frame plates.
[Operation and effect of the second invention]
According to the second aspect of the present invention, when the valve operation link is fixed to lock the valve, the lock pin is supported by both the frame plates, so that the valve operation link is locked by the cantilever pin. Therefore, the valve can be locked in the neutral position more reliably.

It is a partial side view of the tractor which attached the front loader which shows main embodiment. It is a side view of the operation part of the switching valve which shows main embodiment. It is a rear view of the operation part of the switching valve which shows main embodiment. It is a top view of the operation part of the switching valve which shows main embodiment. It is a cross-sectional top view of the support part of the operation lever which shows main embodiment. It is a partial cross-sectional top view of the operation part of the switching valve which shows main embodiment. It is a partial vertical side view of the lock structure of the valve operation link which shows main embodiment. It is a perspective view of the operation part of the switching valve which shows main embodiment. It is a disassembled perspective view of the valve operation link which shows main embodiment. It is a side view of the operation part of the switching valve which shows 2nd Embodiment. It is a rear view of the operation part of the switching valve which shows 2nd Embodiment. It is a top view of the operation part of the switching valve which shows 2nd Embodiment. It is a partial longitudinal cross-sectional plan view of the operation part of the switching valve which shows 2nd Embodiment. It is a partial vertical side view of the lock structure of the valve operation link which shows 2nd Embodiment. It is a perspective view of the operation part of the switching valve which shows 2nd Embodiment. It is a disassembled perspective view of the valve operation link which shows 2nd Embodiment.

  FIG. 1 shows a partial side view of a tractor equipped with a front loader R. The tractor includes a four-wheel drive type traveling machine body 3 having a front wheel 1 and a rear wheel 2 and a driving seat 4, a steering wheel 5 for steering the front wheels, a driving step 6, and the like.

  The traveling machine body 3 is configured by connecting a front part of a machine body where an engine (not shown) is arranged and a transmission case 9 at the rear part of the machine body by an intermediate housing 10 having a sheet metal hollow structure. The engine is covered with a bonnet 11, and a front axle case 13 on which the left and right front wheels 1 are mounted and supported so as to be freely steerable is supported on a front frame 12 connected to the engine so as to be able to roll. The wheel 2 is pivotally supported.

  The engine power is axially transmitted to a hydrostatic continuously variable transmission (HST) 14 directly connected to the front end of the transmission case 9 for continuously variable transmission in the forward and reverse directions. 9 is gear-shifted in multiple stages and transmitted to the left and right rear wheels 2, and the front-wheel driving power branched from the rear-wheel transmission system is transmitted to the front of the fuselage and transmitted to the front axle case 13. It has become.

  A part of the engine power input to the continuously variable transmission 14 is transmitted as it is to the PTO transmission system in the transmission case 9 without being shifted, and a rear PTO shaft (not shown) provided at the rear portion of the transmission case 9. ) And the live PTO power that rotates at a constant speed regardless of the traveling speed from the mid PTO shaft 16 installed at the bottom of the mission case 9.

  On the right side of the driving step 6, a shift pedal 17 that is urged to return to neutral is provided and linked to a shift operation shaft (not shown) of the continuously variable transmission 14. A pair of left and right side brake pedals 18 are arranged in front of the right side of the driving step 6.

  A front loader R is detachably connected to the front portion of the traveling machine body 3. The hydraulic device that drives the front loader R is equipped as follows.

  A switching valve 25 is fixedly arranged on the right side of the driver's seat 4, and an operation lever 26 for switching the switching valve 25 is once extended forward and then extended upward. As shown in FIGS. 1 to 4, the switching valve 25 is provided with two three-position switching type spool valves 23, 24 in front and rear and linked to an operating lever 26 as will be described later. It is configured such that pressure oil can be supplied to and discharged from two sets of hydraulic circuits by 26 cross operations.

  Four pipe connection members 28 having self-closing pipe connection ports 28a are mounted in a vertical line at the right front position of the operation step 6, and each of the pipe connection members 28 and the switching valve 25 has four. The metal pipes 29 are connected in communication.

  The front loader R pivotally connects the boom 32 to the support frame 31 connected and fixed to the front left and right of the traveling machine body 3 so that the boom 32 can swing up and down, and pivotally connects the bucket 33 to the tip of the boom 32 so as to swing the dump truck. A boom cylinder 34 and a bucket cylinder 35, each of which is composed of a return-acting cylinder, are connected to four pipe connection members 28 by pressure-resistant hydraulic hoses 36, respectively.

  The operation structure of the switching valve 25 is shown in FIGS. Support brackets 40 and 41 as frame plates are erected on the front and rear sides of the switching valve 25 above the valve body 25a with a predetermined interval across the valve operation links 38 and 39 via the substrate 37. A bent piece 40a toward the other (front) support bracket 41 is formed at the upper end of one (rear) support bracket 40, and left and right extending between the end of the bent piece 40a and the other support bracket 41. The lateral boss portion 42 is fixed in a state where the lateral boss portion 42 is supported in the longitudinal direction along the axial center x of the laterally supporting shaft 30.

  A first operation fitting 43 having a U-shaped planar shape is pivotally mounted so as to be rotatable around a lateral axis x, and a second operation fitting is rotatable on the first operation fitting 43 around a fulcrum y in the front-rear direction. 44 is pivotally supported, and the base end portion 26 a of the operation lever 26 is fixed to the upper surface of the second operation fitting 44.

  Boss portions 46 for supporting the front and rear support shafts 45 are formed on the pair of front and rear support brackets 40 and 41, respectively. The boss portions 38a and 39a at the base ends of the valve operation links 38 and 39 are axially centered on the front and rear support shafts 45 The valve operation links 38 and 39 are pivotally supported so as to swing up and down around a, and the free ends of the valve operation links 38 and 39 are connected to the spool valves 23 and 24 by pins 47, respectively.

  As shown in FIG. 3, the operating point (position of the pin 47) on the spool valves 23, 24 side, the axis a (fulcrum) of the longitudinal support shaft 45, and the linkage fittings 48b, 49b (force point) are on the back surface. The lock pin 55 is arranged on a straight line L as viewed and positioned so as to be positioned directly above the axis a (fulcrum) of the longitudinal support shaft 45.

  The valve operation links 38 and 39 include boss portions 38a and 39a through which the longitudinal support shaft 45 is inserted, and a long hole 38b through which a pin 47 connected to the spool valve 23 is connected to the other end side with the boss portions 38a and 39a as base ends. , 39b is formed in a bifurcated shape having U-shaped arm portions 38c, 39c in a plan view and bent pieces 38d, 39d formed on the opposite side of the boss portions 38a, 39a from the arm portions 38c, 39c. Arm portions 38e and 39e.

  As shown in FIGS. 2, 4, and 5, an operation arm 43 a extends rearward from the first operation fitting 43, and an operation pin extends from the second operation fitting 44 toward the left, right, laterally inward. 44a is extended. The operation arm 43a and the bent piece 39d of one of the valve operation links 39 are interlocked and connected through rods 48 having linking fulcrum 48a and 48b with ball fulcrums at both ends, and the operation pin 44a and the other valve operation. The bent piece 38d of the link 38 is interlocked and connected via a rod 49 having linkage metal fittings 49a and 49b with ball fulcrums attached to both ends.

  Accordingly, when the grip 26b of the operation lever 26 is in the neutral position of the front, rear, left and right, both spool valves 23 and 24 are in the neutral position, and when the grip 26b of the operation lever 26 is moved forward or backward from the neutral position, the first When the operation fitting 43 is rotated around the lateral fulcrum x and one of the spool valves 24 is slid up and down and the grip 26b of the operation lever 26 is moved from the neutral position to the left or right, the second operation fitting 44 is obtained. Is rotated around the fulcrum y in the front-rear direction, and the other spool valve 23 is slid up and down.

  When the front loader R is mounted, the boom cylinder 34 is connected to a hydraulic circuit switched by one spool valve 24 and the bucket cylinder 35 is connected to a hydraulic circuit switched by the other spool valve 23. In this case, when the grip 26b of the operation lever 26 is operated forward from the neutral position, the boom cylinder 34 is shortened and the boom 32 is lowered, and when the grip 26b of the operation lever 26 is operated rearward from the neutral position, the boom cylinder 34 is extended. It operates and the boom 32 is raised. When the grip 26b of the operation lever 26 is operated rightward from the neutral position, the bucket cylinder 35 is extended and the bucket 33 is dumped downward, and when the grip 26b of the operation lever 26 is operated leftward from the neutral position, the bucket cylinder 35 is The piping is set so that the bucket 33 is scooped and raised by the shortening operation.

  Locking brackets 51 and 52 are provided upright on the boss portion 38a of the valve operation link 38 and the arm portion 39e of the valve operation link 39, respectively. 51a and 52a are formed. Boss portions 53 and 54 are formed on the front and rear support brackets 40 and 41, and a lock pin 55 for mechanically fixing and holding the operation lever 26 in a neutral position is provided on the long boss portion 54 attached to the support bracket 41. It is inserted. A downward L-shaped locking portion 55 a is fixed to the outer end (front end) of the lock pin 55. On the outside (front side) of the support bracket 41, a horizontal receiving plate 56 having two locking holes 56a and 56b is attached. The lower end of the L-shaped locking portion 55a is slidably in contact with the upper surface of the receiving plate 56 by its own weight.

  The lock pin 55 is operated by a crank-shaped lock operating tool 57. An arm 58 that engages with the locking portion 55 a of the lock pin 55 is provided at the lower end of the lock operation tool 57. The arm 58 includes a long hole 58a that engages with the locking portion 55a and a downward positioning pin 58b.

  On the upper part of the lock operation tool 57, a downward grip part 57a bent in an inverted U shape is provided. When the grip part 57a is slightly lifted and slightly swung right or left, the lifting of the grip part 57a is loosened. The positioning pin 58b of the arm 58 gets out of the locking hole 56a (or 56b) of the receiving plate 56 and rides on the receiving plate 56. When the lock operating tool 57 is moved and the positioning pin 58b is slid on the receiving plate 56 with the lower end of the positioning pin 58b being in contact with the receiving plate 56, the positioning pin 58b is engaged with the engaging hole 56b (or 56a). At the same time, the lower end portion 57b of the grip portion 57a is fitted into the lock positioning portion 59R (or the unlocking positioning portion 59U) of the positioning means 59, and the lock operating tool 57 is positioned.

  When the operation lever 26 is in the neutral position, the arm 58 is swung by operating the operation tool 57, and the lock pin 55 is inserted into the locking pin hole 51a of the brackets 51, 52 via the locking portion 55a. The spool valves 23 and 24 are locked or unlocked by being inserted into and removed from 52a. Positioning means 59 having a lock positioning portion 59R for positioning the grip portion 57a at the lock position r and an unlocking positioning portion 59U for positioning at the lock release position u is provided on the upper portion of the rear wheel fender on the right side portion of the driver seat 4. is there.

  When not in operation, with the operating lever 26 set to the neutral position, as shown by a two-dot chain line in FIGS. By setting the lower end portion 57b of the portion 57a to the lock positioning portion 59R, the lock pin hole 51a formed in the brackets 51, 52 attached to the valve operation links 38, 39 of the spool valves 23, 24, The operation lever 26 is mechanically fixed at the neutral position by being inserted into the boss portion 53 formed in the support bracket 40 while being inserted through the 52a. At the time of work, from the state where the operation lever 26 is mechanically fixed to the neutral position, the grip 57a of the lock operation tool 57 is locked from the locked state of the lock operation tool 57 as shown by the solid line in FIGS. By setting the positioning portion 59R to the unlocking positioning portion 59U, the lock pin 55 is disengaged from the locking pin holes 51a and 52a of the brackets 51 and 52 of the operation links 38 and 39, and the cross operation of the operation lever 26 is allowed. Will come to be.

  As described above, in the hydraulic device in this embodiment, the two spool valves 23 and 24 for the two hydraulic devices are linked to the single operation lever 26, and the operation lever 26 is moved in the first direction (front-rear direction). It is configured to be operable in a second direction (left and right direction) intersecting the first direction, and is configured to operate the spool valves 23 and 24 separately by operating the operation lever 26 in the first and second directions. . In the linkage mechanism between the two spool valves 23 and 24 and the operation lever 26, valve operation links 38 and 39 respectively connected to the respective valves are interposed, and the valve operation links 38 and 39 are sandwiched between them. A pair of frame plates (support brackets 40 and 41) hold boss portions 42 for supporting the left and right support shafts 30 for operating the operation lever 26 in the first direction (front-rear direction) from both sides. The respective valve operation links 38 and 39 for individually operating the two spool valves 23 and 24 are swingably supported by the support shafts 45 provided on the pair of support brackets 40 and 41, and the lock pin 55 is supported by the support bracket 41. In the two valve operation links 38 and 39, pin holes 51a and 52a are formed in the two valve operation links 38 and 39 through brackets 51 and 52 formed integrally therewith, so that the two spool valves 23 and 24 are provided. When the lock pin 55 is in the neutral position, the lock pin 55 is inserted into the pin holes 51a and 52a by the lock operation of the lock operation tool 57, and the valve operation links 38 and 39 are fixed to lock the spool valves 23 and 24. It is.

  As a result, the boss portion 42 that supports the support shaft 30 of the operation lever 26 is held from both sides by the pair of support brackets 40 and 41 provided with the valve operation links 38 and 39 interposed therebetween, so that the support brackets 40 and 41 themselves are strong. The boss part 42 is also firmly held by the support brackets 40 and 41, and even if the operation lever 26 is operated in two directions, the boss part 42 does not shake, so that the support shaft 30 can be reliably supported, The operation lever 26 does not deviate from the first direction, and a light lever operation can be performed.

  When the two spool valves 23, 24 are in the neutral position, the two lock valves 55 are inserted into the plurality of pin holes 51a, 52a formed in the two valve operation links 38, 39 so that the two valves The operation links 38 and 39 are simultaneously fixed to lock the spool valves 23 and 24. That is, the spool valves 23 and 24 are inserted into the holes 51a and 52a formed in the two valve operation links 38 and 39 provided separately for operating the two spool valves 23 and 24, respectively. Since the valve is to be locked, the valve operation links 38 and 39 for operating the spool valves 23 and 24 are operated even in any of the first direction (front-rear direction) and the second direction (left-right direction). Since the valve is reliably locked at the valve neutral position, the spool valves 23 and 24 can be reliably locked at the neutral position even if there is play on the operation lever 26 side.

[Another embodiment]
(1) FIGS. 10 to 16 show a second embodiment. In the following, points of the locking means different from the main embodiment described above will be described, and other configurations other than those described later are the same as those of the main embodiment. As shown in FIGS. 13 and 14, locking pin holes 50 penetrating in a line are formed in the bifurcated arm portions 38 e and 39 e of the valve operation links 38 and 39. A bracket 61 having a boss portion 54 is attached to the support bracket 41, and a lock pin 55 formed by bending a locking portion 55b upwardly into an L shape is inserted into the boss portion 54. A bracket 63 having pin holes 62 formed concentrically with the plurality of pin holes 50 when the operation lever 26 is in the neutral position is attached to the rear support bracket 40. On the upper part of the bracket 61, a horizontal receiving plate 56 having a locking hole 56b is attached to the outside (front side) of the support bracket 41.

  As shown in FIG. 11, the operating point (position of the pin 47) on the spool valve 23, 24 side, the axial center a (fulcrum) of the longitudinally supporting shaft 45, the axial center of the lock pin 55, the linkage metal 48b, 49b (power point) is arranged on a straight line L in a rear view, and the lock pin 55 is arranged so as to be positioned at the left and right intermediate part between the front and rear support shaft 45 and the connecting brackets 48b and 49b. Yes.

  The arm 58 at the lower end of the lock operating tool 57 is provided with a long hole 58a that engages with an upward L-shaped locking portion 55a and a downward positioning pin 58b.

When the lock operating tool 57 is located at the unlocking position u, the downward positioning pin 58b formed on the arm 58 is disengaged to the front side beyond the front end (front end) of the receiving plate 56, and the positioning pin 58b The lower end is lower than the upper surface of the receiving plate 56. In order to lock the spool valves 23 and 24 from this state, if the handle 57a of the lock operating device 57 is slightly lifted and slightly swung rightward to loosen the lift of the handle 57a, the positioning pin 58b of the arm 58 is released. Ride on the backing plate 56. When the lock operating tool 57 is further moved to the right while the lower end of the positioning pin 58b is in contact with the receiving plate 56, and the positioning pin 58b is slid on the receiving plate 56, the positioning pin 58b enters the engaging hole 56a. Simultaneously with the fitting, the lower end portion 57b of the grip portion 57a fits into the lock positioning portion 59R, and the lock operating tool 57 is positioned. In the locked state, the lock pins 55 are inserted into all the pin holes 50 formed in the arm portions 38e and 39e and the pin holes 62 formed in the bracket 63, and the valve operation links 38 and 39 are fixed. Is locked.
(2) Although the switching valve 25 uses the spool valves 23 and 24 in the above-described embodiment, a rotary valve may be used.

  The present invention can be applied to a tractor provided with a snow removal device and a mowing device in addition to the front loader R.

23, 24 Valve 26 Operation lever 30 Support shaft 38, 39 Valve operation link 40, 41 Frame plate 42 Boss part 50 Pin hole 51a, 52a Pin hole 55 Lock pin

Claims (2)

Two valves for two hydraulic devices are linked to a single operating lever, the operating lever is configured to be operable in a first direction and a second direction intersecting the first direction, and the operating lever is In the hydraulic device for a work vehicle configured to operate in the first and second directions and operate the valves separately,
A pair of frame plates provided with a valve operation link connected to each valve in a linkage mechanism between the two valves and the operation lever, and sandwiching the valve operation link, Holding the boss part that supports the spindle that operates in the first or second direction from both sides,
Each of the two valve operating links for operating the two valves separately is supported on a support shaft provided on the pair of frame plates, and a lock pin is provided on the frame plate. A pin hole is formed in the operation link, and when the two valves are in a neutral position, the valve operation link is fixed by inserting the lock pin into the pin hole by a lock operation using a lock operation tool. A hydraulic device for a work vehicle, characterized by locking.   The lock pin is supported by one frame plate of the pair of frame plates when the valve is unlocked, and both of the pair of frame plates are fixed when the valve operation link is fixed to lock the valve. The hydraulic device for a work vehicle according to claim 1, wherein the hydraulic device is supported by the vehicle.

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