JP3471432B2 - Valve systems for traveling vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve system for controlling a power shift transmission of a traveling vehicle such as a tractor. In a tractor, a power shift transmission has a forward / reverse switching mechanism serving as a main clutch, a main transmission mechanism, an auxiliary transmission mechanism, a front-wheel equal-speed switching mechanism, and a differential lock mechanism. And
These mechanisms can be switched using a hydraulic clutch, a cylinder, and the like. A solenoid valve is used as a valve for controlling a hydraulic clutch, a cylinder, and the like of the forward / reverse switching mechanism.
The type that directly controls the large hydraulic pressure becomes large, the type that controls the control valve indirectly by using pilot hydraulic pressure becomes small, and the pilot valve is used in the above-mentioned centralized arrangement. Is known to be preferred. [0004] In the prior art pilot control valve, the control valve and the pilot valve are independent and connected by a long oil passage, so that pressure loss or oil leakage or the like is caused. Therefore, the responsiveness is low, the size of each is small, but the total occupied area is large, the cost is high, and the piping is troublesome. Accordingly, the present invention has as its main object to provide a valve system which has high responsiveness, is small in size, and can be manufactured at low cost, by disposing a control valve and a pilot valve close to a spool hole formed in a valve body. Aim. The technical measures taken by the present invention to solve the above problems are the valve body 11
And a pair of spool holes 12 concentrically sandwiching the partition wall 11a.
And a pair of control valves BF and BR for controlling the supply of hydraulic oil to the front / reverse actuators AF and AR of the forward / reverse switching mechanism.
Of the control valves BF, BR
The pool 13 is inserted into one spool hole 12 and the other
The spool 13 of the control valves BF and BR is inserted into the other spool hole.
12 and the respective spool holes 12 on the partition wall 11a side.
Operates on actuators AF and AR on the opposite end side
The pilot oil sliding the spool 13 oil state supplied with connecting pilot oil passage P for supplying the pilot valve C to control the supply of pilot oil
F, provided the CR spool 13 and placed opposite the spool
13 is provided with pilot oil at the end opposite to the partition 11a side.
Peripheral groove 13a so as to form a space for supplying
And the end of the spool 13 is
Return spring 3 interposed between each spool 13 and 11a
By 0, the pilot valve CF, Toe abutment in the valve support 14 of the CR, and the valve support 14, communicates with the spool bore 12 and counter to the partition wall 11a of the spool 13
A drain hole 14a closed by the valve body 17 closed by the opposite end face and moved by the solenoid 16,
A pilot hole for each spool hole 12 is provided in the valve body 11.
And the check valve 33
WF and WR are formed through which the pressure oil can be drained via a pressure relief valve 32. The spool 13 has an end face on the opposite side to the partition wall 11a side and a spool.
In order to allow the portion of the hole 12 to which the pilot oil is supplied to communicate with the drain hole 14a, a communication passage 13 formed of a slit is formed.
b is formed. [0007] A spool hole 12 formed in the valve body 11
A spool 13 constituting the control valves BF and BR;
The pilot valves CF, C
R, and the pilot valves CF, CR
When the pilot oil passage P is controlled by the
A pilot pressure is applied to the end of the control valve and the control valve slides against the return spring 30 to control the control valves BF and BR. An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 to 13, reference numeral 2 denotes a transmission case in which a tractor transmission is built in, an inspection opening 3 is formed on the upper surface, and a cover 4 for closing the opening 3 so that it can be opened and closed is attached. An inner valve unit 5 is provided on the inner surface of the cover 4 via a separate plate 8.
Exterior valve units 6 are mounted on the outer surface, respectively, to constitute a valve system. As shown in FIG. 12, the valve system controls almost all actuators required for traveling of the tractor. The actuators include actuators AF and AR of a forward / reverse switching mechanism, and a main transmission mechanism. Actuators A1 to A4, actuators AL and AH of the auxiliary transmission mechanism, actuators AJ and AG of the front and rear wheel differential lock mechanism, and actuators AD and AE of the front-wheel equal-speed switching mechanism. An actuator A of each of these mechanisms is a hydraulic clutch for connecting a rotating shaft and a transmission gear, a hydraulic cylinder for engaging a differential lock body with the differential gear, and the like, and a hydraulic cylinder for moving a shifter engaged with the transmission gear. It may be. The exterior valve unit 6 is shown in FIGS.
As shown in FIG. 0, a main clutch control valve BM that supplies pressure oil to actuators AF and AR of a forward / reverse switching mechanism and control valves BL and BH that control actuators AL and AH of a subtransmission mechanism are provided to the outer valve body 21. When,
A pressure detection switch R communicating with each of these control valves B
M, RL, and BH are attached. The control valve B
Electromagnetic proportional valves are used for M, BL, and BH, which are larger than a control valve B for pilot control described later. K is a supply oil passage for supplying pressure oil connected to the hydraulic pump 7, which is formed through the inside of the outer valve body 21 and communicates with the control valves BM, BL, BH.
Distribution holes K1 and K2 are branched from the supply oil passage K.
Further, the outer valve body 21 has an actuator operating oil passage SJ for supplying an actuator operating oil to the actuators AJ and AG of the front and rear wheel differential lock mechanism and the actuators AD and AE of the front wheel constant speed switching mechanism.
Connecting tools 22J, 22G, 2 forming SG, SD, SE
2D and 22E are provided. The cover 4 has eight outlet holes QF, QR, Q1 through Q1 through which the actuator hydraulic oil flows within the thickness.
4, QL and QH are formed, and the take-out holes QF, QR, Q1 to Q4, QL and QH are formed at one end on the inner surface side with the actuators AF and AR of the forward / reverse switching mechanism, the actuators A1 to A4 of the main speed change mechanism and the auxiliary A connector connection port NF connected to each of the actuators AL and AH of the transmission mechanism,
NR, N1 to N4, NL, and NH are formed, and a take-out hole Q1 for the actuators A1 to A4 is formed on the outer surface of the cover 4.
To Q4 are provided with pressure detection switches R1 to R4. The pressure detection switches RM, RL, BH,
R1 to R4 are provided for detecting the pressure of the corresponding control valve B and controlling the operation timing in a sequence. Cover 4 facing the separate plate 8
A pair of left and right actuator oil supply oil grooves 23 communicating with the communication hole K2, and a pair of left and right pilot oil supply pilot fluids communicating with the communication hole K1 on both left and right sides of the joint surface (lower surface). Each of the grooves 24 is formed to be long, and a pressure reducing valve 25 is provided in the communication hole K1 to generate low-pressure pilot oil from high-pressure actuator operating oil. The left and right supply oil grooves 23 and the left and right pilot oil grooves 24 communicate with each other on the left and right. 1, 2 and 8 to 11, the interior valve unit 5 is provided with ten sets of valves in which a control valve B and a pilot valve C are combined. In the inner valve body 11, a spool hole 12 is formed concentrically with a central partition wall 11a interposed therebetween.
They are arranged in columns. The control valves BF, BR and the pilot valves CF, CR are for a forward / reverse switching mechanism, the control valves B1 to B4 and the pilot valves C1 to C4 are for a main speed change mechanism, the control valves BL, BH, and the pilot valve C.
L and CH indicate those for the auxiliary transmission mechanism, respectively. A supply oil chamber α, a hydraulic oil chamber β, and a drain oil chamber γ are formed in the inner valve body 11 so as to face the respective spool holes 12. The chamber β is selectively communicated with a supply oil chamber α and a drain oil chamber γ on both sides, and supply of hydraulic oil from the supply oil chamber α to the actuator A via the hydraulic oil chamber β, and a hydraulic oil chamber β, The discharge of hydraulic oil from the actuator A can be controlled via the drain oil chamber γ. Each supply oil chamber α communicates with the supply oil groove 23 through an oil hole 35 of the separate plate 8 and supplies oil chambers α for control valves BF and BR of a forward / reverse switching mechanism.
Are communicated with each other through a communication hole 36 in the inner valve body 11. Each hydraulic oil chamber β of the control valves BF and BR of the forward / reverse switching mechanism and the control valves B1 to B4 of the main transmission mechanism
Are oil grooves formed on the joint surface side of each of the separate plates 8 of the inner valve body 11 and the outer valve body 21 and hydraulic oil holes TF, TR, T1 to T1 formed on the separate plate 8.
Through T4, take-out holes QF, QR, Q in cover 4
1 to Q4. One of the control valves BL and BH of the auxiliary transmission mechanism is taken out through the oil groove 37 of the outer valve body 21 and the other is taken out through the hole of the separate plate 8 and the oil groove 38 of the inner valve body 11. Is in communication with Control valves BJ of the front and rear wheel differential lock mechanism,
The hydraulic oil chambers β of the BG and the BD and the BE of the front-wheel equal-speed switching mechanism include oil grooves in the inner valve body 11, hydraulic oil holes TJ, TG, TD, TE formed in the separate plate 8, the cover 4, and the outer valve body. It communicates with the connectors 22J, 22G, 22D, 22E through four holes 27 of 21. Actuator operating oil passages SF, SR for supplying controlled hydraulic oil to each actuator A by means of the operating oil chamber β, the operating oil hole T, the take-out hole Q, the oil grooves 37, 38, the holes 27, etc. , S1 to S4, SL, SH,
SJ, SG, SD, SE (shown in FIG. 12) are formed. The oil drain passages γ of the control valves B are communicated with each other, and are opened from the oil drain groove 28 of the cover 4 to the transmission case 2 via the separate plate 8 from the inner valve body 11. Actuator A for forward / reverse switching mechanism
The supply oil chambers α of the control valves BF and BR for F and AR are communicated with each other through an oil passage 36, and the hydraulic oil from the main clutch control valve BM can be supplied to the oil passage 36. An end of a valve support 14 is inserted and fixed to an end of each spool hole 12 of the inner valve body 11. A drain hole 14 a communicating with the spool hole 12 is formed in each of the valve supports 14.
A ball valve 17 that opens and closes 4a is provided.
Each of the valve supports 14 is provided with a solenoid 16, and the solenoid 16 is capable of closing the drain hole 14a by exciting the valve body 17 when excited. The spool 13 is urged by a return spring 30 so that the end thereof comes into contact with the valve support 14.
The valve support 14 also serves as a position regulating member for the spool 13. As shown in FIG. 13, the spool 13 is formed with a peripheral groove 13a at an end and a communication path 13b formed of a slit at an end face communicating with the peripheral groove 13a. Drain hole 14a inside
Also communicates with. The communication passage 13b may be formed by a hole. An electromagnetic pilot valve C is constituted by the valve support 14, the solenoid 16, and the end of the valve element 17. The pilot valve C is paired with each control valve B so as to face the spool 13. Are arranged concentrically and symmetrically with the partition wall 11a therebetween. As shown in FIG. 11, the inner valve body 11 and the separate plate 8 have oil passages UF, UR, which communicate with the circumferential groove 13a of the spool 13 of each control valve B.
U1 to U4, UJ, UG, UD, and UE are formed. Each oil passage U communicates with the left and right pilot oil grooves 24 of the outer valve body 21 to form a pilot oil passage P. Each oil passage U is provided with a throttle t (shown in FIG. 12), and maintains a pilot pressure between each throttle t and the pressure reducing valve 25. Therefore, the oil passages UF, UR, U1 to U4, U
Pilot oil supplied to the open end side of the spool hole 12 via J, UG, UD, and UE passes through the circumferential groove 13a of the spool 13 and the communication passage 13b when the solenoid 16 of the pilot valve C is demagnetized. When the solenoid 16 is excited by being drained from the drain hole 14a, the drain hole 1
Since the valve 4a is closed by the valve element 17, the peripheral groove 13a and the communication passage 13b are filled, a pilot pressure is applied to the end of the spool 13, and the spool 13 is pushed against the return spring 30 to supply. The oil chamber α can communicate with the hydraulic oil chamber β. The separate plate 8 regulates undesired oil flow between the cover 4 and the inner valve body 11 and also controls the supply oil groove 23, the pilot oil groove 24 and the inner valve body 11 opposed thereto. A supply oil hole 35 for transferring oil, a hydraulic oil hole T, and an oil passage U are formed between the oil passage U, the supply oil chamber α, the working oil chamber β, and the like. The working oil passage S and the pilot oil passage P communicate with each other. Referring to FIGS. 1, 2 and 12, control valves BF and AR for actuators AF and AR of a forward / reverse switching mechanism are provided.
In the spool hole 12 of the BR, there is provided a restraining member 9 made of a rod material penetrating the partition wall 11a and slidably supported by the partition wall 11a. When one of the spools 13 of the symmetrically arranged control valves BF and BR is pressed by the pilot pressure, the restraint member 9 is pushed by the one spool 13 and contacts the other spool 13.
The movement of the other spool 13 is regulated, and the control valve B
F and BR are not operated at the same time. The spool holes 1 of the control valves BF, BR for the actuators AF, AR of the forward / reverse switching mechanism.
2 are connected to depressurizing oil passages WF, WR formed in the inner valve body 11, and therefore these oil passages WF, WR are connected to pilot valves CF, CR for a forward / reverse switching mechanism. Are communicated with the oil passages UF and UR that communicate with each other. A check valve 33 is interposed in each of the oil passages WF, WR, and these oil passages WF, W
R merges and is connected to the pressure relief valve 32.
By providing a shuttle valve that allows only the pressurized oil from one side to flow to the depressurizing valve 32 at the merging portion 50 of the oil passages WF and WR, one check valve 33 can be shared by one valve. it can. The pressure release valve 32 can be operated by manual operation or by further depressing the clutch pedal 47 from a normal depression range (a range for operating the main clutch control valve BM). Actuator AF for forward / reverse switching mechanism,
Pilot oil selectively supplied to the spool holes 12 of the AR control valves BF and BR presses the check valve 33,
Even if the drain holes 14a of the pilot valves CF and CR are closed by the valve element 17, the pressing force of the spool 13 by the pilot pressure is released. The spool 13 is returned by the spring 30 and the actuators AF, A
The operation of R is released, and the forward / reverse switching mechanism is set to the neutral state. In FIG. 12, hydraulic oil discharged from the hydraulic pump 7 among the triple pumps 7, 40, 41 driven by the engine passes through the steering controller 42 and is then supplied to the PTO clutch valve 43. The oil whose pressure has been adjusted here is supplied to the supply oil passage K of the outer valve body 21 of the valve system, and at the same time, the oil whose pressure has been adjusted to the lubricating oil is supplied to the actuators AF, AR, A1
To A4, AL, AH, AJ, AG, AD, AE. The hydraulic oil discharged from the other pumps 40 and 41 is supplied to the actuator 4 of the working machine mounted on the tractor.
It is supplied to the hydraulic device 46 for raising and lowering the five and three point links.
The hydraulic oil that has entered the supply oil passage K is directly supplied to the main clutch control valve BM and the control valves BL and BH, and the control valves B1 to B4, BJ, BG and B
D and BE, and supplied to the control valves BF and BR via the main clutch control valve BM. Further, the oil becomes pilot oil via the pressure reducing valve 25 of the circulation hole K1 and becomes pilot oil CF, CR, C1 of the interior valve unit 5.
To C4, AL, AH, CJ, CG, CD, CE. The main clutch control valve BM operates when the pilot valve C
The control valves BL and BH are operated in conjunction with F and CR, and are operated when the auxiliary transmission mechanism is switched between high and low or in conjunction with the pilot valves A1 to A4 of the main transmission mechanism. BL and BH are directly electrically controlled to perform pressure control for reducing shock during shifting, and the actuator hydraulic oil is supplied to the actuator A
L, supply to AH. Pilot valves CF, CR, C1-C
4. By electrically controlling the AL, AH, CJ, CG, CD, CE, the drainage of the pilot oil is regulated, and the control valves BF, BR, B1 to B4, BJ, BG, BD, B
The spool 13 of E is pushed by the pilot pressure to switch the valve, the actuator hydraulic oil is sent from the supply oil passage K to the actuator hydraulic oil passage S, and the actuators AF, A
R, A1 to A4, AL, AG, AD, and AE are appropriately operated. According to the present invention described in detail above, a pair of control valves for controlling the supply of hydraulic oil to the front / reverse actuators AF and AR of the forward / reverse switching mechanism are provided in the valve body 11. In a valve having a pair of spool holes 12 into which spools 13 of BF and BR are respectively inserted, a spool 1 is provided at one end side of the spool 13 of each spool hole 12.
3 is connected to a pilot oil path P for supplying pilot oil that slides against the return spring 30, and pilot valves CF and CR for controlling the supply of the pilot oil are provided so as to face the spool 13. One end of the spool 13 is brought into contact with the valve support 14 of the pilot valves CF and CR, and the spool hole 12
1 that is in communication with the valve and that is moved by the solenoid 16
7 has a drain hole 14a which can be closed.
An oil path between the control valves BF, BR and the pilot valves CF, CR is not required, the response is high, and the device can be manufactured small and inexpensively. In addition, in particular, in the present invention, in addition to the above-described structure, the pressure relief valve is connected to the valve body 11 at one end of the spool 13 of each spool hole 12 and is joined via the check valve 33 and is released. Since the pressure relief oil passages WF and WR capable of draining the pressure oil through the pressure relief oil passage 32 are formed, the pressure relief valve 32 is operated to drain the pressure oil of the spool hole 12 through the pressure relief oil passages WF and WR. Thus, the depressurizing valve 32 can be operated even if the operating means of the forward / reverse switching mechanism, for example, the forward / backward switching lever is kept at either the forward or reverse switching position. The forward / reverse switching mechanism can be intermittently operated by one operating means such as a pedal. Further, since the communication passage 13b for connecting the pilot oil passage P to the drain hole 14a is formed in the spool 13, even if the pressure relief oil passages WF and WR are provided as described above, the pressure relief can be performed. The back pressure can be prevented from acting on the oil passages WF, WR. That is, the communication passage 13b
In the mechanism in which one end of the spool 13 is brought into contact with the valve supports 14 of the pilot valves CF and CR, the pressure oil in the pilot oil passage P slightly displaces the spool 13 against the return spring 30. To create a gap,
Since the drain hole 14a is drained, the spool hole 12
A slight pressure builds up on one end side of the inner spool 13 and acts as a back pressure on the depressurizing oil passages WF and WR. However, this back pressure can be eliminated by providing the communication passage 13b.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional plan view showing a main part of the present invention. FIG. 2 is a cross-sectional plan view of the entire valve system of the traveling vehicle. FIG. 3 is a side view of the entire valve system. FIG. 4 is a plan view of the exterior valve unit. FIG. 5 is a cross-sectional plan view of the exterior valve unit. FIG. 6 is a sectional view taken along line XX of FIG. 4; FIG. 7 is a sectional view taken along line YY of FIG. 4; FIG. 8 is an explanatory plan view showing an oil passage in the valve system. FIG. 9 is a sectional view taken along line ZZ of FIG. 2; FIG. 10 is a plan view showing an oil passage on the interior valve unit side. FIG. 11 is a plan view showing an oil passage of a separate plate. FIG. 12 is a hydraulic circuit diagram of the valve system. FIG. 13 is a perspective view of a spool. [Description of Signs] 11 Inner valve body 12 Spool hole 13 Spool 14b Communication path 14 Valve support 14a Drain hole 16 Solenoid 17 Valve 32 Pressure relief valve 33 Check valve AF Actuator AR Actuator BF Control valve BR Control valve CF Pilot valve CR Pilot valve P Pilot oil passage WF Depressurized oil passage WR Depressurized oil passage

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yuichi Kitao 64 Ishizukitamachi, Sakai City, Osaka Kubota Sakai Works Co., Ltd. (56) References JP-A-50-100713 (JP, A) 157704 (JP, U) Japanese Utility Model Showa 62-98856 (JP, U) Japanese Patent Publication No. 50-6373 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 61/26-61 / 36 F16H 63/00-63/36

Claims (1)

(57) [Claim 1] A partition (11 ) is provided on a valve body (11).
a) A pair of spool holes (12) are formed concentrically across the a).
And a pair of control valves (BF) and (BR) for controlling the supply of hydraulic oil to the front / reverse actuators (AF) and (AR) of the forward / reverse switching mechanism.
One of the control valves (BF) and (BR)
Lube (BF) and (BR) spools (13)
Inserted into the pool hole (12) and the other control valve (B
F), (BR) spool (13) is inserted into the other spool hole.
(12), and the partition wall of each spool hole (12)
At the end side opposite to the (11a) side , an actuator
A pilot oil path (P) for supplying pilot oil that slides the spool (13) to supply hydraulic oil to (AF) and (AR) and a pilot valve (P) for controlling the supply of this pilot oil CF) and (CR) are provided so as to face the spool (13) , and the spool (13)
At the end opposite to the partition (11a) side of
(13) so as to form a space for supplying
a) and the end of the spool (13) is
Interposed between the partition (11a) and each spool (13)
By a return spring (30) is a pilot valve (CF), the valve support (CR) abutment Toe (14), to the valve support (14), a spool bore (12)
With the partition (11a) side of the spool (13)
A drain hole (1) closed at the opposite end face and closable by a valve element (17) moved by a solenoid (16).
4a), the valve body (11) is connected to a portion of each spool hole (12) to which the pilot oil is supplied, is joined via a check valve (33), and is depressurized (32). ) To form depressurized oil passages (WF) and (WR) through which the pressurized oil can be drained, and the spool (13)
A spool hole is provided on the end face opposite to the partition wall (11a) side.
(12) A valve system for a traveling vehicle, wherein a communication passage (13b) formed of a slit is formed to communicate a portion to which the pilot oil is supplied to the drain hole (14a).