JPH06889Y2 - Flow control valve adjustment device for work vehicles - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial field of application The present invention relates to a flow control valve adjusting device for controlling the raising and lowering of a working machine in a working vehicle such as a tractor, and more specifically, a stopper for controlling the operating range thereof. Regarding

(B) Conventional technology Generally, in a work vehicle, for example, a tractor, a working machine such as a rotary installed on a machine body is switched to an ascending / descending position, and a plowing work or a scraping work is performed while traveling while the working machine is grounded. There is. At this time, the control valve is switched by the lever operation of the operator, the oil is discharged from the actuator for lifting the working machine, and the working machine in the raised position is lowered.
When a large amount of oil is discharged from the actuator when the working machine descends, the working machine drops at once and is grounded, and a dashing phenomenon occurs especially when a rotary working machine is used.

Therefore, in order to prevent problems such as the dashing phenomenon, a flow control valve is installed in the housing, and the valve controls the flow rate of oil discharged from the actuator to slowly lower the working machine.

The above-mentioned flow control valve is such that a check valve including a valve body or the like for urging the oil passage in a closing direction is installed in an oil passage communicating from the hydraulic pump to the actuator for lifting work equipment, and the valve of the check valve is installed. By moving the body with an adjusting screw, the gap formed between the valve body and the oil passage is changed to adjust the flow rate of oil discharged from the actuator side.

(C) Problems to be solved by the device However, the adjusting screw is directly screwed into the housing, and the stepped portion provided in the oil passage is directly brought into contact with the valve body of the check valve to be attached by the spring. Because of the biasing structure, it was necessary to form the seat for receiving the valve body in the stepped portion separately from the processing of the oil passage in the housing. In addition, it is not only necessary to separately install a member for retaining the adjust screw in the oil passage after incorporating the adjust screw in the oil passage, and the retainer member is made up of a simple member such as a snap ring. Because it ’s just
The retaining ring was sometimes broken.

Further, a mechanism for restricting the rotation of the adjusting screw within a predetermined range is separately provided between the adjusting screw and the housing.

(D) Means for Solving the Problem The present invention is intended to solve the above-mentioned problems, and includes a housing 2 provided with an oil passage 25 communicating with a hydraulic actuator 6 for lifting a working machine. A check valve 42 having a valve body 41 and an adjusting screw 31 having a grip portion 33 are installed, and the valve body 41 of the check valve is operated by a pressing portion 32 at the tip of the screw to move the hydraulic actuator 6 to the oil passage. In a working vehicle in which the amount of oil returned to 25 is controlled, the housing 2 has a protrusion 15 for fixing the cylinder head 11 constituting the hydraulic actuator 6 and receiving a reaction force from the cylinder head. A hole 2 formed in the projecting portion 15 in which the gripping portion 42 is projected to the outside, and the adjusting screw 31 is movably installed in the projecting portion. Sleeve 2 on 2
6 is screwed and fixed, and the sleeve 26 has an internal thread portion 26 that is screwed to the adjusting screw 31 and has an insertion hole 27 that guides the tip of the screw to a position facing the valve body 41; A seat 39, which is arranged to face the body 41 so as to come in contact with and away from the body 41, and an oil passage communicating with the valve body are provided. Through 30
Further, the adjusting screw 3 is attached to the housing 2.
A regulating portion 37 for regulating the rotation of 1 is provided, and the adjusting screw 31 between the grip portion 33 and the plate 31 is provided.
And a stopper member 35 is provided so as to project in a direction orthogonal to the advancing / retreating direction of the screw, and the tip end portion of the stopper member abuts on the regulating portion 37 so that the rotation of the adjusting screw 31 falls within a predetermined range. A flow control valve adjusting device in a working vehicle, characterized in that it is configured to be regulated.

(E) Action Based on the above-described configuration, the restricting portion 37 that restricts the rotation of the adjusting screw 31 and the stopper piece 35 provided on the adjusting screw 31 rotate the adjusting screw 31 to move forward and backward, and the screw 31 causes the check valve. At a position where the adjusting screw 31 is screwed and fixed to the housing 2 via the sleeve 26 so as to form a mechanism for restricting the rotation of the adjusting screw 31 within a predetermined range at a position where the lock screw 42 can be switched between locked and released as appropriate. The position is regulated, and the rotation range is set so that the check valve 42 is properly locked and opened.

(F) Embodiment An embodiment according to the present invention will be described below with reference to the drawings.

As shown in FIG. 3, the working machine lifting hydraulic device 1 of the tractor includes a hydraulic actuator 6 including a piston 3 and a cylinder 5 housed in a housing 2,
The piston 3 is connected to a lift arm 10 via a piston rod 7 and a lift fork 9. Further, one side of the cylinder 5 is closed by a cylinder head 11,
The cylinder head 11 is fixed to a head fixing portion 12 formed on the housing 2 by a plurality of bolts 13 ... As shown in FIGS. 4 and 5, the housing 2 is formed with protrusions 15 and 16 on both sides of the head fixing portion 12 so as to protrude toward the front of the tractor. By being formed in a rib shape so as to project outward from the head fixing portion 12, the fixing portion 12 that receives a large reaction force from the cylinder 5 is reinforced so that the fixing portion 12 can receive a larger reaction force. I am configuring. Furthermore,
A flow control valve 17 is installed on the protrusion 15, a priority valve 18 is fixed on one side of the protrusion 15, and a control valve 19 is arranged on one side of the protrusion 16. ing. In addition, 20, 2 in the figure
Reference numerals 1 and 2 are a hydraulic inlet and a top link bracket, respectively.

On the other hand, as shown in FIGS. 1 and 2, the flow control valve 17 has a round hole 22 having a female screw portion 22a at one end formed in the housing 2 and is used for raising and lowering the working machine from the round hole 22. The oil passage 23 communicating with the hydraulic actuator 6 and the oil passage 25 communicating with the control valve from the main pump are formed. Further, the sleeve 2 is provided in the round hole 22.
6 is screwed in, and the sleeve 26 is formed with an insertion hole 27 having one end formed with a female screw portion 26a.
Communication hole 26b for communicating the insertion hole 27 with the oil passage 25
Has been drilled. On the other hand, in the insertion hole 27, a plate 29 provided at the center thereof is biased by a spring 30 to screw an adjusting screw 31 in an oil-tight manner, and a pressing portion 32 is formed at one end of the screw 31. Further, a grip portion 33 is provided at the other end. The adjusting screw 3 is provided near the grip 33.
The stopper piece 35 is fitted and fixed in the fitting hole 31a formed in No. 1, and the stopper piece 35 is attached to the screw 31.
With the advancing and retreating of the above, it is configured to come into contact with the stopper receiving portion 37 fixed to the housing 2 side by the bolt 36. A valve seat 39 is formed at the other end of the sleeve 26, and a ball 41 urged toward the sleeve 26 by a spring 40 is in oil-tight contact with the valve seat 39. The check valve 42 is thus configured. Note that reference numerals 43 and 45 in the figure respectively denote a plug member and a lock nut.

Next, the hydraulic circuit will be described with reference to FIG.

The main pump 45 communicates with the tank T via the filter F, and also communicates with the priority valve 18 provided in the oil passage 46, which connects the oil passage 46 to the oil passages 47 and 49. It is split. And the oil passage 4
7 is a solenoid valve 5 for operating the lift cylinder 50
1 and the hydraulic actuator 6 is provided in the oil passage 49.
A control valve 19 for operation is provided, and the flow control valve 17 is provided between the adjusting screw 6 and the control valve 19. The sub-pump 52 communicates with the tank T through the filter F and also with the power steering 53. In the figure, reference numeral 55 is a relief valve.

Since the present embodiment is configured as described above, when the adjusting screw 31 is rotated to move forward and backward, and the pressing portion 32 sets the ball 41 of the check valve 42 to the position where it can be appropriately switched between the locked state and the open state. With the stopper receiving portion 37 removed from the housing 2, the stopper piece 35 is fitted and fixed in advance in the fitting hole 31a of the adjusting screw 31, and the screw 31 is rotated to lock and open the check valve 42. After moving to an appropriate position where the state can be switched, the stopper receiving portion 37 is fixed to the housing 2 with the bolt 36 at the position. As a result, the stopper piece 3
When the screw 5 is engaged with the stopper receiving portion 37 when the screw 31 is rotated, the screw 31 is restricted in its advance / retreat position.

Then, when adjusting the descending speed of the working machine by installing a working machine such as a rotary on the tractor in preparation for the plowing work, for example, when the grip portion 33 is rotated so that the adjusting screw 31 moves toward the check valve 42, The screw 31 advances while rotating and the ball 41 is pushed by the pressing portion 32.
Is pressed against the biasing force of the spring 40. For this reason, the ball 41 is moved to move the valve seat 3 of the sleeve 26.
A gap is formed between this and 9. When oil is supplied from the main pump 45 through the oil passage 25 by the lever operation of the operator, the oil is further sent to the communication hole 26b and the insertion hole 27, and the ball 41 resists the urging force of the spring 40. Press. As a result, the gap between the ball 41 and the valve seat 39 formed by the adjustment of the adjusting screw 31 is further widened, and the oil is sent to the oil passage 23 at a large flow rate and press-fitted into the hydraulic actuator 6. The machine is raised. When the operator lowers the working machine, the weight of the working machine causes the oil extruded from the hydraulic actuator 6 to be throttle-controlled by the gap between the valve seat 39 and the ball 41, so that the flow rate is small. It is sent to the oil tank T. Therefore, the piston 3 of the hydraulic actuator 6 moves slowly in the cylinder 5, and the working machine is lowered toward the field scene at a low speed. Furthermore, since the stopper piece 35 abuts the stopper receiving portion 37 at a predetermined position when the adjusting screw 31 moves forward and backward, the screw 3
1 does not move more than necessary.

When the engaging position of the stopper piece 35 is bad and it is desired to make a fine adjustment, first, the bolt 36 is loosened and the stopper receiving portion 37 is rotated by a small amount about the bolt 36 to move the stopper receiving portion 37. The engagement position can be changed, and the position of the stopper piece 35 can be appropriately slid to finely adjust by adjusting the lock nut 45.

Further, in this embodiment, the stopper receiving portion 37 is detachably installed in the housing 2 with the bolt 36, and when the engaging position of the stopper receiving portion 37 and the stopper piece 35 is adjusted, the stopper receiving portion 37 is removed. By removing 37 from the housing 2, the adjustment screw 31 is structured such that the work can be performed with the stopper piece 35 still installed. However, as shown in FIGS. 7 and 8, the stopper receiving portion 56 is , A hexagon bolt is screwed into the housing 2, and the stopper receiving portion 56 is attached to and detached from the housing 2 so that the stopper piece 35 can be engaged and released, and the stopper receiving portion 56 can be rotated. Therefore, the height and the head position of the hexagonal bolt may be changed to finely adjust the engagement position with the stopper piece 35.

Further, as shown in FIG.
a and a female screw portion 31b is formed on the adjusting screw 31 so that the adjusting screw 31 is pulled out from the tip to the fitting hole 31a, and a bolt portion 33a screwed to the female screw portion 31b is formed.
The grip portion 33 may be rotated to advance toward the fitting hole 31a, and the stopper piece 35 fitted in the fitting hole 31a may be horizontally pressed to be held.

(G) Effect of the Invention As described above, according to the present invention, the adjusting screw 31 can be moved back and forth, and the receiving seat 39 is disposed opposite to the valve body 41 so as to come in contact with and separate from the valve body 41, and the sleeve having the oil passage formed therein. A plate 29 in which 26 is screwed and fixed to the housing 2 and attached to the outer end portion of the sleeve and the adjusting screw 31.
A spring 30 is provided between the housing 2 and the housing 2 and a restricting portion 3 for restricting the rotation of the adjusting screw 31.
7, the regulating portion 37, the grip portion 33, and the plate 29 are provided.
Since a mechanism for restricting the rotation of the adjusting screw 31 within a predetermined range is interposed between the adjusting screws 31, the oil passage of the stepped portion for receiving the valve body is formed in the housing of a large product, and the stepped portion is formed. No complicated processing is required to form the seat of the valve body. Further, the adjusting screw 31 is used for the housing 2 for fixing the cylinder head 11.
Since it is provided on the protrusion 15 formed on the
A large pressure acting on the cylinder head 11 from the cylinder 5 can be surely carried by the protrusion 15 of the housing 2, and since the protrusion 15 has a thick structure, the oil passages 23, 25 and the large diameter The hole 22 can be easily formed without lowering the strength, and the sleeve 26 can be screwed for the first time with the large-diameter hole 22, and the adjusting screw 31 can be screwed into the sleeve so as to be able to advance and retract. It becomes possible to further lengthen the adjusting screw 31, and the screw 31 is largely projected to the outside of the projecting portion 15 so that the spring 3 is provided between the screw 31 and the grip portion 33.
It is possible to install the plate 29 for zero insertion and the stopper member 35 for restricting the rotation range. Furthermore, the sleeve 26
Since the spring 30 is provided between the outer end of the adjusting screw 31 and the plate 29 attached to the adjusting screw 31, the unidirectional frictional biasing force is always applied to the screw portion of the adjusting screw 31 with an extremely simple structure. Therefore, it is possible to surely prevent the screw 31 from blindly moving due to machine vibration or the like and inadvertently changing the throttle amount. And housing 2
A regulating portion 37 is provided on the adjusting screw 3
1 is provided with the stopper member 35, the stopper member 3
The contact range of the adjusting screw 31 with the regulating member 37 can regulate the range of rotation of the adjusting screw 31, and the adjusting screw 31 can be excessively turned to eliminate the restriction of the hydraulic pressure. It is possible to surely prevent the occurrence of the above, and it is possible to surely prevent an erroneous operation such as removing the adjusting screw 31.

[Brief description of drawings]

1 is a side sectional view showing a flow control valve according to the present invention, FIG. 2 is a front view thereof, FIG. 3 is a side sectional view taken along line III-III of FIG.
4 is a plan view thereof, FIG. 5 is a front view thereof, FIG. 6 is a view showing a hydraulic circuit, FIG. 7 is a side sectional view showing another embodiment in which a stopper is a hexagon bolt, and FIG. It is the front view. FIG. 9 is a side sectional view showing another embodiment in which the stopper pin support structure is changed. 2 ... Housing 6 ... Hydraulic actuator 15 ... Projection 17 ... Flow control valve 22 ... (Round) hole 23,25 ... Oil passage 26 ... Sleeve 29 ... Plate 30 ... Spring 31 ... Adjust screw 32 ...... Pressing part 33 ...... Grip part 35 ...... Stopper piece 37 ...... Stopper receiving part 39 …… Catching seat 41 …… Ball (valve element) 42 …… Check valve

Claims (1)

[Scope of utility model registration request] 1. A check valve having a valve body and an adjusting screw having a grip portion are installed in a housing provided with an oil passage communicating with a hydraulic actuator for raising and lowering a working machine, and the check valve is provided at a pressing portion at the tip of the screw. In a working vehicle in which the amount of oil returned from the hydraulic actuator to the oil passage is controlled by operating the valve body of, the housing fixes the cylinder head that constitutes the hydraulic actuator, and Has a projecting portion for receiving the reaction force of, and the grip portion is projected to the outside so that the adjusting screw can be moved forward and backward, and a sleeve is screwed and fixed to the hole formed in the projecting portion. ,
Also, the sleeve has an internal thread portion that is screwed into the adjustment screw, and an insertion hole that guides the tip of the screw to a position facing the valve body; , An oil passage communicating with the valve body, and further, a spring is interposed between the outer end portion of the sleeve and a plate attached to the adjusting screw, and the housing is provided with a rotation of the adjusting screw. In addition to providing a regulating portion for regulating, a stopper member is provided on the adjusting screw between the grip portion and the plate so as to project in a direction orthogonal to the advancing / retreating direction of the screw, and the tip end portion of the stopper member has the regulating portion. A flow control valve for a working vehicle, which is configured so as to come into contact with a wheel and regulate the rotation of the adjusting screw within a predetermined range. Breakfast adjustment device.