JP2007290621A - Multi-axle vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-axle vehicle by which a front steering shaft and an intermediate steering shaft can always be steered properly at the same time even when an inside leak occurs in each hydraulic switching valve. <P>SOLUTION: A servo valve V<SB>1</SB>and an intermediate part independent mode-switching valve V<SB>2</SB>are interposed in a line communicating from a pressure source P<SB>S</SB>to a head side oil chamber and a rod side oil chamber of right and left intermediate part cylinders 3a, 3b of an intermediate part oil pressure circuit 3, and a line communicating from the head side oil chamber and the rod side oil chamber of the right and left intermediate part cylinders 3a, 3b to a tank. An end of a rotatable first link L<SB>1</SB>supported by a pin at a longitudinal intermediate part is connected to a front end of a rod of a right front part cylinder 2b of a front part oil pressure circuit 2, and the other end is connected to a spool of the servo valve V<SB>1</SB>. An end of a rotatable second link L<SB>2</SB>being supported by a pin at the longitudinal intermediate part and having the length of a predetermined link ratio to the first link L<SB>1</SB>is connected to a sleeve of the servo valve V<SB>1</SB>, and the other end is connected to a front end of a rod of the right intermediate part cylinder 3b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement in a multi-shaft vehicle in which a traveling body is provided with at least three or more steering shafts, and more specifically, each hydraulic switching valve of each hydraulic circuit for steering the wheels of each steering shaft, and the like. The present invention relates to a multi-shaft vehicle that can prevent the deviation of the steering angle of wheels caused by internal leak.

  As a multi-axle vehicle such as a wheel crane equipped with a steering device having a special steering mode, a vehicle having a configuration as described later is known. The steering device for a multi-axis vehicle according to this conventional example is intended to provide a steering device for use in a multi-axis vehicle body that can steer intermediate wheels at a steering angle corresponding to the arrangement position thereof. The outline of the steering device for a multi-shaft vehicle according to this conventional example will be described below with reference to FIG. 13 of the hydraulic circuit diagram of the steering device controlled by the steering valve.

That is, when the intermediate wheels 2 _C and 2 _C are arranged at positions close to the rear wheels 2 _R and 2 _R , one end side is connected to the output ports A ₂ and B ₂ of the second valve V ₂ of the valve unit V. first and second wheel steering cylinder _R C after steering the rear wheels ₂ R, _{2 R} by the intermediate and rear wheel steering conduit, and _{R C} ', the intermediate ring ₂ C, _2-wheel steering cylinder _{after C} a steering was At the time of clamp steering, it communicates with intermediate steering cylinders C _C and C _C ′ having a larger diameter than Rc and Rc ′, via a third switching valve V ₃ having a clamp steering position V ₃₁ and a club steering position V _32. Both the bottom and rod side pressure chambers are utilized, and at the time of club steering, the bottom side pressure chambers are communicated with each other to utilize the rod side pressure chambers.

In short, when the front wheel steering shaft and the rear wheel steering shaft are steered in the same phase or in opposite phases, the steering speed of the intermediate wheel steering shaft between the rear wheel steering shaft and the rear wheel steering shaft becomes a small angular velocity. In this way, it is controlled by a switching valve. The angular velocity is changed by switching the pressure receiving area of the hydraulic cylinder with the same amount of hydraulic oil. The one connected to the output ports A ₁ and B ₁ of the first valve V ₁ of the valve unit V and connected to the first and second front wheel steering pipes is connected to the front wheels 2 _F and 2 _F. Front wheel steering cylinders F _C and F _C ′ to be steered (see, for example, Patent Document 1).
JP 2002-160661 A

In the technology according to the conventional example described above, switching of each hydraulic switching valve is performed in order to set the steering angle of the wheel of each steering shaft to an optimum value, but internal leakage of each hydraulic switching valve cannot be ignored.
That is, in the repetitive operation of the steering control means, a difference occurs in the amount of hydraulic oil supplied to the cylinder that steers the wheel of each steering shaft due to an internal leak of each hydraulic switching valve, and an angular difference occurs in the steering angle of the wheel. Therefore, it deviates from the target steering angle.

  The deviation of the steering angle of the wheel of each steering shaft from the target steering angle hardly poses a problem when traveling at a low speed or moving at a short distance in the field. However, when such a steering control means is adopted in a multi-axis vehicle that travels on a public road at a high speed for a long distance, it is difficult to always properly and appropriately steer the front wheel steering shaft and the intermediate wheel steering shaft at the same time. In addition to problems in running, there are also problems such as uneven wear of tires that are wheels, which is not preferable.

  Accordingly, an object of the present invention is to provide a multi-shaft vehicle that makes it possible to always properly steer the front steering shaft and the intermediate steering shaft at the same time even if each hydraulic switching valve has an internal leak. It is.

  The present invention has been made in view of the above circumstances. Therefore, in order to solve the above-mentioned problems, the means adopted by the multi-axle vehicle according to claim 1 of the present invention is that the pressure oil switching means is replaced by the trapezoidal link. The left and right front cylinders that steer the left and right wheels of the front steering shaft that are synchronously steered by a front hydraulic circuit that includes a hydraulic line that supplies hydraulic oil and a trapezoidal link In the multi-shaft vehicle having a steering control means having an intermediate hydraulic circuit for supplying hydraulic oil to the left intermediate cylinder and the right intermediate cylinder for steering the left and right wheels of the intermediate steering shaft, the intermediate hydraulic circuit A first intermediate line communicating with the rod side oil chamber of the left intermediate cylinder and the head side oil chamber of the right intermediate cylinder, the head side oil chamber of the left intermediate cylinder, and the rod side oil chamber of the right intermediate cylinder. Communication A second intermediate portion line, a position where both the first intermediate portion line and the second intermediate portion line are blocked, and a hydraulic oil supply line extending from the first intermediate portion line and the pressure source, and a second intermediate portion A 4-port 3-position servo valve is provided to connect the line and the tank to the communication position, the first intermediate section line and the tank to communicate with each other, and the second intermediate section line and the pressure source to communicate with each other. One rod of the front cylinder and the spool of the servo valve are connected by a first link, and the rod of the intermediate cylinder on the side to which the first link is connected and the sleeve of the servo valve are connected by a second link. And the first link and the second link are supported rotatably at a longitudinal position where the link ratio is in accordance with the steering ratio of the front steering shaft and the intermediate steering shaft. Features It is intended.

  The means adopted by the multi-axle vehicle according to claim 2 of the present invention is the multi-axle vehicle according to claim 1, wherein the servo valve and the left-right middle of the first intermediate line and the second intermediate line are used. The middle part of the 4-port 2 position is switched to a position where the first intermediate part line and the second intermediate part line communicate with each other and a position where the first intermediate part line and the second intermediate part line are blocked. A mode switching valve is interposed, and the first branch line and the second branch line branched from each of the first intermediate line and the second intermediate line communicate with the hydraulic oil supply line via the direction switching valve. The direction switching valve is configured to connect the position where the first branch line and the second branch line are shut off, the first branch line and the hydraulic oil supply line, and the second branch line. Tan Is a 4-port 3-position valve that switches between a position for communicating the first branch line and the tank and a position for communicating the second branch line and the hydraulic oil supply line. is there.

  The means adopted by the multi-axle vehicle according to claim 3 of the present invention is the multi-axle vehicle according to claim 1, wherein the pressure source is at the end of all hydraulic oil supply lines to the left and right front cylinders. The high pressure is selected and used.

  In the multi-shaft vehicle according to the first aspect of the present invention, the hydraulic oil is supplied by operating the pressure oil switching means to operate the left and right front cylinders for steering the left and right wheels of the front steering shaft of the front hydraulic circuit. Then, the spool of the servo valve is operated via the first link, and hydraulic oil is supplied from the sleeve port of the servo valve via the first intermediate line and the second intermediate line, so that the left and right intermediate cylinders are operated. To do. Since the steering amount of the intermediate cylinder is transmitted to the sleeve of the servo valve via the second link, the sleeve moves. However, hydraulic oil enters and exits the left and right intermediate cylinders according to the difference in the movement amount of the spool and the sleeve. By doing so, it becomes neutral. In this case, since the relative positions of the spool and the sleeve do not change, the steering amount of the intermediate cylinder is always a steering amount corresponding to the steering ratio of the wheels of the front steering shaft and the intermediate steering shaft. Therefore, according to the multi-axle vehicle according to the first aspect of the present invention, even if there are internal leaks in the servo valve and each cylinder, the steering angle of the left and right wheels of the front steering shaft and the wheel of the intermediate steering shaft There is no difference in the relationship with the steering angle of the vehicle, and there is no deviation from the target steering angle, so it is possible to safely drive on public roads at high speeds for long distances, and the tires that are wheels wear unevenly. There is no such thing.

  In the multi-axis vehicle according to claim 2 of the present invention, the intermediate independent mode switching valve interposed between the servo valve and the left and right intermediate cylinders of the first intermediate line and the second intermediate line, By making the first intermediate part line and the second intermediate part line communicate with each other, an effect similar to that of the multi-axle vehicle according to the first aspect can be obtained. Further, by switching the intermediate independent mode switching valve to a position where the first intermediate line and the second intermediate line are cut off, the steering of the left and right wheels of the front steering shaft and the steering of the wheels of the intermediate steering shaft are linked. Can be separated. Then, the steering of the left and right wheels of the front steering shaft is intermediated by switching the direction switching valve interposed between the first branch line and the second branch line branched from the first intermediate line and the second intermediate line, respectively. Steering of the wheel of the part steering shaft can be performed individually. Therefore, according to the multi-axle vehicle according to claim 2 of the present invention, it is possible to obtain an effect that the narrow space penetration is improved and positioning can be performed within a short time in the field.

  When left and right front cylinders that steer the left and right wheels of the front steering shaft and left and right middle cylinders that steer the wheels of the intermediate steering shaft are used as separate pressure sources, pressure is generated even when the steering wheel is not operated. This is not preferable for energy saving. However, in the multi-axle vehicle according to claim 3 of the present invention, the pressure source is the R port or L port of the pressure oil switching means, and operates the left and right intermediate cylinders that steer the wheels of the intermediate steering shaft. Therefore, it is not necessary to provide a separate pressure source, so that an energy saving effect can be obtained.

  Hereinafter, the multi-axle vehicle according to the first embodiment of the present invention will be described with reference to the accompanying drawings, taking as an example the case of a multi-axle vehicle having three axles. FIG. 1 is a system diagram of a front hydraulic circuit and an intermediate hydraulic circuit of a steering control means of a multi-axis vehicle, and FIG. 2 is a schematic configuration explanatory diagram of a trapezoidal link of the multi-axis vehicle. 3 is an explanatory diagram of the steering ratio of the wheels of the front steering shaft and the intermediate steering shaft, and FIG. 4 shows the left and right wheels of the front steering shaft and the intermediate steering shaft of the multi-axle vehicle individually. It is explanatory drawing in the case of steering.

  Reference numeral 1 shown in FIG. 1 is a steering control means for a multi-axis vehicle according to Embodiment 1 of the present invention. The steering control means 1 includes a front steering shaft including a trapezoidal link 21 having a configuration described later. A front hydraulic circuit 2 for steering left and right wheels (not shown) is provided. Further, an intermediate hydraulic circuit 3 for steering left and right wheels of the intermediate steering shaft (not shown) is provided.

  The trapezoidal link 21 is configured as shown in FIG. That is, an arm 22 that rotates according to the steering of the left and right wheels 20 of the respective steering shafts, and a tie rod 23 that is smaller than the base end dimension between the arms 22 and connects the distal ends of the arms 22 and 22. The connecting portion is freely bendable. The reason why the left and right wheels 20 are synchronously steered via the trapezoidal link 21 is that the turning radii of the left and right wheels 20 during steering are different and the steering angles of the left and right wheels 20 need to be different.

  The front hydraulic circuit 2 that constitutes the steering control means 1 is a pressure oil switching means 1a that is a dual-type integral power steering valve (IPS) that switches the discharge amount and the discharge direction of hydraulic oil by rotating the handle 1b left and right. Thus, the operation of the left and right front cylinders 2a and 2b for steering the left and right wheels of the front steering shaft is operated. Further, the operation of the left and right intermediate cylinders 3a and 3b of the intermediate hydraulic circuit 3 is operated in conjunction with the operation of the left and right front cylinders 2a and 2b.

The pressure-oil switching means 1a comprises, in order toward the tip side from the left side of the handle 1b side in the figure, the 2L port _{P L2,} the 2R port _{P R2,} the 1L port _{P L1,} the second 1R port _{P R1} provided ing. Therefore, the front hydraulic circuit 2 is provided with a first front line 2c that communicates the rod side oil chamber of the left front cylinder 2a from the first 1R port P _R1 of pressure-oil switching means 1a, from the 1L port P _L1 A third front line 2e communicating with the rod-side oil chamber of the right front cylinder 2b is provided. In addition, a second front line 2d that communicates from the second R port _PR2 to the head side oil chamber of the right front cylinder 2b is provided, and a fourth that communicates from the second L port _PL2 to the head side oil chamber of the left front cylinder 2a. A front line 2f is provided. Note that one end is connected to the pressure oil switching means 1a and the other end is connected to the tip of the rod of the left front cylinder 2a is a pressure oil switch depending on the amount of expansion and contraction of the rod of the left front cylinder 2a. This is a mechanical link 1c for obtaining a feedback function for adjusting the amount of inflow from the means 1a into the left front cylinder 2a and the right front cylinder 2b.

The intermediate hydraulic circuit 3 includes a first intermediate line 3c that communicates with the rod-side oil chamber of the left intermediate cylinder 3a and the head-side oil chamber of the right intermediate cylinder 3b, and the head-side oil of the left intermediate cylinder 3a. And a second intermediate line 3d communicating with the chamber and the rod side oil chamber of the right intermediate cylinder 3b. These and first middle line 3c to the second intermediate portion line 3d, the servo valve V ₁ of the four-port three-position to be described later is interposed. Servo valve V ₁ of the this four-port three-position, the first intermediate portion line 3c and the position for blocking together the second intermediate portion line 3d, hydraulic oil feed line 3e extending from the first intermediate portion line 3c and the pressure source P _S with communicating the position for communicating the second intermediate portion line 3d and the tank T, a first intermediate portion line 3c and the tank T in conjunction with communicating the position for communicating the second intermediate portion line 3d and the pressure source P _S The three positions can be switched.

Said first intermediate portion line 3c and the servo valve V ₁ and the left and right central cylinders 3a of the second middle line 3d, between 3b, intermediate portion independent mode switching valve V 4 port 2 position of the structure to be described later ₂ is interposed. The intermediate portion independent mode switching valve V ₂ is set to the position for communicating said first intermediate portion line 3c and the second intermediate portion line 3d, and a position for blocking the first middle line 3c and the second intermediate portion Rye 3d It is configured so that it can be switched to two positions.

The first branch line 3f branches from the first intermediate line 3c, and the second branch line 3g branches from the second intermediate line 3d. The first branch line 3f and the second branch line 3g are and communicates with the tank T hydraulic oil feed line 3e via the directional control valve V ₃ to be described later. The directional control valve V ₃ is set to the position to block the first branch line 3f and the second branch line 3g, the first branch line 3f and the hydraulic oil feed line 3e with communicating, a second branch line 3g and the tank T The first branch line 3f and the tank T are communicated with each other, and the second branch line 3g and the hydraulic oil supply line 3e can be switched to three positions.

Then, the right and left front cylinder 2a, one of 2b, i.e. the side where the rod and the servo valve V ₁ spool of right front cylinder 2b is the first link L _1, also the first link L ₁ connected right intermediate portions sleeve of the rod and the servo-valve V ₁ of the cylinder 3b of the are connected by the second link L _2. The first link L ₁ and the second link L ₂ both rotate in the middle of their longitudinal direction via a rotation fulcrum pin on a bracket projecting from a carrier frame of a multi-axis vehicle (not shown). Supported as possible. The rotation support position of these links by the rotation fulcrum pin is a position where the link ratio according to the steering ratio of the wheel between the front steering shaft and the intermediate steering shaft is obtained. In this example, each link is connected to the right cylinder, but may be connected to the left cylinder.

More specifically, as shown in FIG. 3, the stroke of the right front cylinder 2b is l _1, a stroke l ₂ of the servo valve V ₁ spool stroke of the sleeve servo valve V ₁ is l ₃ , and the stroke of the right intermediate portion cylinder 3b is assumed to be l _4. The dimension between the dimension between the coupling portion and the rotation support position of the first link L ₁ in the right front portion cylinder 2b is a _1, the connecting portion of the spool rotational support position and the servo valve V ₁ Is a ₂ , the dimension between the connecting portion of the servo valve V ₁ of the second link L ₂ and the rotation support position is a ₃ , and the connection portion between the rotation support position and the right intermediate cylinder 3 b. dimension between the is assumed to be a _4. Since the relative positional relationship between the spool and the sleeve of the servo valve V ₁ does not change, l ₂ = l ₃ . The dimension a ₂ of the first link L ₁ = the dimension a ₃ of the second link L ₂ and the ratio of the dimension of the first link L ₁ to a ₁ and the dimension of the second link L ₂ to a ₄ ( The link ratio) a ₁ / a ₄ is set to be the steering ratio l ₁ / l ₄ of the wheel between the front steering shaft and the intermediate steering shaft.

Hereinafter, the operation mode of the multi-axis vehicle according to the first embodiment of the present invention will be described in the case where the steering of the wheels of the front steering shaft and the intermediate steering shaft is interlocked. In this case, since the intermediate portion independent mode switching valve V ₂ is not energized, is in a position where the first middle line 3c and the second intermediate portion line 3d is communicated, the directional control valve V ₃ is first branch line 3f And it is in the neutral position which interrupts | blocks the 2nd branch line 3g. Accordingly, the hydraulic oil flows through a line indicated by a thick line in FIG. That is, when hydraulic oil is supplied by operating the handle 1b of the pressure oil switching means 1a and the left and right front cylinders 2a and 2b for steering the left and right wheels of the front steering shaft of the front hydraulic circuit 2 are operated, Since the spool of the servo valve V ₁ is operated via the link L ₁ and hydraulic oil is supplied from the sleeve port of the servo valve V ₁ via the first intermediate line 3c and the second intermediate line 3d, The rods of the intermediate cylinders 3a and 3b expand and contract.

The central cylinder 3a, the steering amount of 3b (amount of expansion and contraction of the rod). However sleeve to be transmitted to the sleeve of the servo valve V ₁ through a second link L ₂ moves, the movement amount of the spool and sleeve servo valve V ₁ by the left and right central cylinders 3a, hydraulic oil 3b enters and exits in accordance with the difference becomes a neutral state. In this case, since the relative position between the spool and sleeve servo valve V ₁ was unchanged, the steering amount of the central cylinder always steering according to the steering ratio of the wheels of the front steering shaft and an intermediate portion steering shaft It becomes quantity. Therefore, according to the multi-axle vehicle according to a first embodiment of the present invention, even if there is internal leakage in the servo valves V ₁ and the cylinders, the left and right wheels of the front steering shaft steering angle and the intermediate portion steering There is no difference in the relationship between the steering angles of the left and right wheels of the shaft, and there is no deviation from the target steering angle, so it is safe to travel on public roads at high speeds for long distances. There is no uneven wear on the tire.

Further, in the multi-axle vehicle according to Embodiment 1 of the present invention, the left and right wheels of the front steering shaft and the intermediate steering shaft can be individually steered. When the steering individually the left and right wheels of the front steering shaft and an intermediate portion steering shaft, as shown in FIG. 4, the intermediate portion independent mode switching valve V ₂ by the excitation of the solenoid, the first middle line The position is switched to the position where both 3c and the second intermediate line 3d are cut off. Thus, the left and right central cylinders 3a via the servo valve V _1, since the hydraulic oil 3b is not supplied, the right and left front cylinder 2a, 2b and the left and right central cylinders 3a, the interlocking state of 3b is released. Therefore, the hydraulic oil flows through a line indicated by a thick line in FIG.
That is, the right and left front cylinder 2a, 2b may be operated by a handle 1b operation of pressure-oil switching means 1a, also by energizing alternately right and left solenoid of the directional control valve V _3, right and left front cylinder 2a, 2b Regardless of the operation, the left and right intermediate cylinders 3a and 3b can be individually operated. Therefore, according to the multi-axle vehicle according to Embodiment 1 of the present invention, it is possible to obtain the effects of improving narrow space penetration and positioning within a short time in the field.

In the multi-axle vehicle according to Embodiment 1 of the present invention, the case where the left and right wheels of the front steering shaft and the intermediate steering shaft are interlocked or individually steered has been described. in the case of multi-axle vehicles it is not necessary to steer the shaft and the left and right wheels of the intermediate portion steering shaft individually, need to central hydraulic circuit 3 an intermediate portion independent mode switching valve V ₂ and the directional control valve V ₃ There is no.

A multi-axis vehicle according to Embodiment 2 of the present invention will be described with reference to FIG. 5 of a system diagram of a front hydraulic circuit of a steering control means and an intermediate hydraulic circuit of the multi-axis vehicle. The second embodiment is different from the first embodiment in that a pressure source for supplying hydraulic oil to the intermediate hydraulic circuit is used as pressure oil switching means, and a directional switching valve V ₃ is provided in the intermediate hydraulic circuit 3. Since the configuration other than that is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and different points will be described.

A check valve is interposed in each of the first front part line 2c and the third front part line 2e in such a direction as to allow the hydraulic oil to flow out of the first front line 2c and the first front oil supply line 2g. Is connected. In addition, a check valve is interposed in each of the second front line 2d and the fourth front line 2f in a direction that allows the hydraulic oil to flow out from the second front line 2d, and the second hydraulic oil supply that joins in the middle is provided. Line 2h is connected. Then, the first hydraulic oil feed line 2g and by a second hydraulic oil supply line 2h is joined, it has a configuration in which a is connected to a pump port of the servo valve V _1.

Hereinafter, the operation mode of the multi-axis vehicle according to the second embodiment of the present invention will be described in the case where the steering of the wheels of the front steering shaft and the intermediate steering shaft is interlocked. In this case, the intermediate portion independent mode switching valve V ₂ is because it is not energized, the first middle line 3c and the second intermediate portion line 3d is in the position that communicates. Accordingly, when the hydraulic oil is supplied by operating the handle 1b of the pressure oil switching means 1a and the left and right front cylinders 2a and 2b for steering the left and right wheels of the front steering shaft of the front hydraulic circuit 2 are operated, Since the spool of the servo valve V ₁ is operated via the link L ₁ and hydraulic oil is supplied from the sleeve port of the servo valve V ₁ via the first intermediate line 3c and the second intermediate line 3d, The rods of the intermediate cylinders 3a and 3c expand and contract.

The central cylinder 3a, the steering amount of 3b (amount of expansion and contraction of the rod). However sleeve to be transmitted to the sleeve of the servo valve V ₁ through a second link L ₂ moves, the movement amount of the spool and sleeve servo valve V ₁ by the left and right central cylinders 2a, 2b in the hydraulic oil in and out in accordance with the difference becomes a neutral state. In this case, do not change the relative positional relationship between the spool and sleeve servo valve V _1, a steering amount of the intermediate section cylinder, always according to the steering ratio of the wheels of the front steering shaft and an intermediate portion steering shaft Steering amount. Therefore, according to the multi-axle vehicle according to the second embodiment of the present invention, the same effect as in the first embodiment can be obtained. Incidentally, when energizing the intermediate portion independent mode switching valve V _2, the right and left front cylinder 2a, 2b and since the left and right central cylinders 3a, the interlocking state between 3b is released, can be steered only wheels of the front steering shaft become.

  A multi-axis vehicle according to Embodiment 3 of the present invention will be described with reference to the accompanying drawings, taking as an example the case of a multi-axis vehicle having a three-axis axle. 6 is a system diagram of the steering control means showing the normal steering state of the multi-axis vehicle, FIG. 7 is a system diagram of the steering control means showing the club steering state of the multi-axis vehicle, and FIG. 8 is a multi-axis type. It is a systematic diagram of the steering control means which shows the clamp steering state of a vehicle. FIG. 9 is a system diagram of the steering control means showing the rear steering axis independent (right) steering state of the multi-axis vehicle, and FIG. 10 is the steering showing the rear steering axis independent (left) steering state of the multi-axis vehicle. It is a systematic diagram of a control means. FIG. 11 is a system diagram of the steering control means showing the intermediate steering axis independent (right) steering state of the multi-axis vehicle, and FIG. 12 shows the intermediate steering axis independent (left) steering state of the multi-axis vehicle. It is a systematic diagram of the steering control means shown. In addition, the same thing as the said embodiment and the thing which has the same function are attached | subjected and demonstrated. 7 to 12, only the positions switched by excitation are displayed.

The steering control means for a multi-axis vehicle according to the third embodiment of the present invention includes a front hydraulic circuit 2, an intermediate hydraulic circuit 3, and a rear hydraulic circuit having the same configuration as that of the multi-axis vehicle according to the second embodiment. and a 4, the front hydraulic circuit 2 and the central hydraulic circuit 3 in series through the front switching valve 2 _V, and is configured to be in communication to the rear hydraulic circuit 4. That is, the fourth front line 2f of the front hydraulic circuit 2 comprises a cylinder-side line 2f ₁ extending from the head-side oil chamber of the left front cylinder 2a, pressure-oil switching extending from the 2L port P _L2 of the pressure-oil switching means 1a It is made from the IPS side line 2f ₂ Metropolitan of means side. These are communicated via the front switching valve _{2 V} is the cylinder side line 2f ₁ and IPS-side line 2f _2. Then, merges with the first hydraulic oil feed line 2g of the front hydraulic circuit 2 and the second hydraulic oil supply line 2h is in communication with the pump port of the servo valve V ₁ of the central hydraulic circuit 3. Of course, the intermediate portion independent mode switching valve V ₂ the first middle line 3c, the second intermediate portion line 3d extends.

Said first intermediate portion line 3c is branched into three, first branch line communicates with the front switching valve 2 _V, the second branch line is left via the third intermediate portion switching valve 3 _V3 The third branch line communicates with the head-side oil chamber of the right intermediate cylinder 3b, and communicates with the rod-side oil chamber of the intermediate cylinder 3a. The third intermediate switching valve _3V3 is connected to the position where the second branch line is communicated with the rod side oil chamber of the left intermediate cylinder 3a by excitation, a fourth intermediate line 3i, an oil return replenishment line which will be described later. 5 through, and a I position is a position to communicate the second intermediate portion switching valve 3 _V2 to be described later. The second intermediate section line 3d is branched into two, the first branch line communicates with the front switching valve 2 _V, the second branch line through the fourth intermediate portions changeover valve 3 _V4 and communicates with the shunt-Atsumariryuben 3 _VF pressure compensated Te.

The left and right from the shunt-Atsumariryuben 3 _VF central cylinders 3a, each of 3b, the third intermediate portion line 3h, which will be described later, is communicated. The third intermediate portion line 3h extend from the two ports of the shunt-Atsumariryuben 3 _VF, the parallel lines meet at the middle branches after merging, communicating with the head-side oil chamber of the left intermediate portion cylinder 3a And the other branch line communicating with the rod side oil chamber of the right intermediate cylinder 4b. The other branch line of the third intermediate part line 3h is filled with a rod-side oil chamber and a tank T of the right intermediate cylinder 3b, which will be described later, by the position where this branch line is communicated and the excitation of the solenoid. second middle switching valve 3 _V2 for switching the 2 position of the J position is a position to communicate is interposed via line 5.

On one of the parallel lines of the third intermediate portion line 3h, the front switching valve 2 _V and the shunt-Atsumariryuben 3 _VF, K position is a position to communicate via the bypass line 3j by the excitation of the solenoid When the first intermediate portion switching valve 3 _V1 for switching the position for communicating the parallel lines of the one is interposed. In this case, as described above, the first intermediate switching valve 3 _V1 is interposed in one of the parallel lines, but it can perform the same function even if it is interposed in the other of the parallel lines. Can do.

  The oil return replenishment line 5 includes an oil return line 5a in which a check valve is interposed so as to return pressure oil of a predetermined pressure or more to the tank T, and an operation in the direction from the tank T to the fourth intermediate line 3i. A check valve is interposed in a direction allowing oil flow, and is composed of an oil replenishment line 5b that branches from the upstream side of the check valve of the oil return line 5a and merges on the downstream side. The oil return replenishment line 5 has an excess or deficiency in the amount of hydraulic oil that reversibly moves between the rod side oil chamber of the left middle cylinder 3a and the rod side oil chamber of the right middle cylinder 3b. When the hydraulic oil is excessive, a part of the hydraulic oil is returned to the tank T. On the other hand, when the hydraulic oil amount is insufficient, the hydraulic oil in the tank T is supplied to the rod side oil chamber of the left intermediate cylinder 3a or the right intermediate cylinder. It functions to replenish the rod side oil chamber 3b.

In this case, since the rod side oil chamber of the left middle cylinder 3a and the rod side oil chamber of the right middle cylinder 3b are reversibly moved, the amount of hydraulic oil is theoretically excessive or insufficient. There is nothing. Actually, however, the processing errors of the left and right intermediate cylinders 3a and 3b and the difference in the processing accuracy of these cylinders, the first, second, third and fourth intermediate switching valves _3V1 , _3V2 , _3V3 and _3V4. It cannot be avoided that the amount of hydraulic oil becomes excessive or insufficient due to internal leakage. However, as described above, the excess or deficiency of the amount of hydraulic oil that moves reversibly is eliminated by the action of the oil return replenishment line 5, so that the left intermediate cylinder 3 a and the right intermediate cylinder 3 b have cavitation, boost pressure, operation failure, etc. Is prevented from occurring.

Said rear hydraulic circuit 4, from the fourth intermediate portion switching valve 3 _V4 of the central hydraulic circuit 3, a first rear portion communicating with the head-side oil chamber of the left rear cylinder 4a, the rod side oil chamber of the right rear cylinder 4b Line 4d is provided. Also it includes a rod-side oil chamber of the left rear cylinder 4a, and a head-side oil chamber of the right rear cylinder 4b, and the second rear line 4e communicating with the fourth intermediate portion switching valve 3 _V4. A pilot check valve 4c is shown enclosed by a one-dot chain line and interposed between lines communicating with the respective ports of the head side oil chamber and the rod side oil chamber of the right rear cylinder 4b. The check valve on the outflow side of the pilot check valve 4c is configured to be opened by the pressure of the hydraulic oil on the inflow side. For example, when hydraulic oil flows into the rod side oil chamber of the right rear cylinder 4b, the check valve on the head side oil chamber side opens, and when hydraulic oil flows into the head side oil chamber of the right rear cylinder 4b, The check valve on the oil chamber side opens.

Incidentally, the front switching valve 2 _V is the cylinder side line 2f ₁ of the front hydraulic circuit 2 causes communication with the pressure-oil switching means side line 2f _2, the first intermediate portion line 3c and the second intermediate portion line 3d N position to shut off is provided. Further, the communicating cylinder side line 2f ₁ to the second intermediate portion line 3d, and a G position for communicating the pressure-oil switching means side line 2f ₂ to the first middle line 3c. Further, the first intermediate portion line 3c with communicating the cylinder side line 2f _1, and a H position for communicating the pressure-oil switching means side line 2f ₂ to the second intermediate portion line 3d. Further, the fourth intermediate portion switching valve 3 _V4 serves to cut off the rear hydraulic circuit 4 and the central hydraulic circuit 3, and a position for communicating the second intermediate portion line 3d in shunt-Atsumariryuben 3 _VF, the solenoid the excitation, the first rear line 4d, via said second intermediate portion line 3d intermediate portion independent mode switching valve V _2, with to communicate with the front switching valve 2 _V, shunt-current of the second rear line 4e The flow valve 3 has an L position which is a position communicating with the _VF .

Further, the a first middle line 3c, near the communicating portion to the front switching valve 2 _V of the second intermediate portion line 3d, the directional control valve V ₃ four-port three-position from pressure source P _S, pilot The hydraulic oil supply / discharge line 6 in which the type check valve 6a is interposed communicates. The directional control valve V ₃ is provided with the a pressure source P _S first middle line 3c, and a neutral position for interrupting the communication between the second intermediate portion line 3d, the pressure source P _S in the first middle line 3c with communicating, and M position for communicating the second intermediate portion line 3d to the tank T, along with communicating the pressure source P _S in the second middle line 3d, N position for communicating the first middle line 3c to the tank T And.

  According to the multi-axis vehicle according to the third embodiment of the present invention, steering is performed in the steering mode of the rear steering shaft alone and the steering mode of the intermediate steering shaft alone, in addition to the steering in the normal steering mode, the club steering mode, and the clamp steering mode. can do. Hereinafter, an operation mode when each steering shaft is steered in each steering mode will be described with reference to FIGS. 6 to 12 sequentially.

Steering of the wheels in the normal steering mode of the multi-axis vehicle according to the third embodiment of the present invention is performed by steering the left and right wheels of the front steering shaft and the intermediate steering shaft. That is, when the steering mode selector switch provided on a driver's seat of the multi-axle vehicle in the normal steering mode, the energization of the solenoid for all of the solenoid valves is stopped, the front switching valve 2 _V is held at the neutral position . Therefore, the hydraulic fluid flows through the front hydraulic circuit 2 and the intermediate hydraulic circuit 3 indicated by bold lines in FIG. 6, and the flow direction of the hydraulic fluid flowing through the front hydraulic circuit 2 and the intermediate hydraulic circuit 3 is controlled. The wheels of the front steering shaft and the intermediate steering shaft are steered.

In this case, the amount of expansion and contraction of the rod of the right front cylinder 2b is transmitted to the spool of the servo valve V ₁ through a first link L _1, also telescopic amount of the rod of right intermediate cylinder 3b via the second link L ₂ It is configured to be transmitted to the sleeve of the servo valve V _1. 5 and FIG. 6, the lines of the front hydraulic circuit 2 and the intermediate hydraulic circuit 3 through which hydraulic oil flows are substantially the same as in the case of the second embodiment. Therefore, in the case of the normal steering mode without exciting the solenoid of all valves, as in the case of the above-described embodiment, even if there is internal leakage if the servo valve V ₁ and the cylinder, the right and left front steering shaft Because there is no difference in the relationship between the steering angle of the wheel and the steering angle of the left and right wheels of the middle steering shaft, there is no deviation from the target steering angle, so it is safe to drive on public roads at high speeds. In addition, the tire that is the wheel does not wear unevenly.

The wheel steering in the club steering mode of the multi-axis vehicle according to the third embodiment of the present invention will be described with reference to FIG. In the steering of the multi-axis vehicle in the club steering mode, all the wheels of the front steering shaft, the intermediate steering shaft, and the rear steering shaft are simultaneously steered in the same direction. In this case, when the steering mode selector switch provided on a driver's seat of the multi-axle vehicle to club steering mode, the intermediate portion independent mode switching valve V ₂ is F position by the excitation of the solenoid, front switching valve _V is switched to the H position, the third intermediate switching valve 3 _V3 is switched to the I position, and the fourth intermediate switching valve 3 _V4 is switched to the L position. Therefore, all the cylinders are controlled by the hydraulic fluid flowing in the line indicated by the thick line in FIG.

That is, in order to steer all wheels to the right, turn off the handle of the pressure-oil switching means 1a on the right side, the 2L port P hydraulic fluid discharged from the _L2 fourth front line 2f of the pressure-oil switching means 1a The IPS side line 2f ₂ , the front switching valve 2 _V , the second intermediate line 3d, and the fourth intermediate switching valve 3 _V4 flow into the first rear line 4d of the rear hydraulic circuit 4. Since the hydraulic oil flowing into the first rear line 4d flows into the head side oil chamber of the left rear cylinder 4a and the rod side oil chamber of the right rear cylinder 4b, the left and right rear cylinders 4a and 4b operate to the left. The hydraulic oil pushed out from the rod side oil chamber of the left rear cylinder 4a and the head side oil chamber of the right rear cylinder 4b passes through the second rear line 4e and the fourth intermediate switching valve _3V4, and is _divided into the intermediate hydraulic circuit 3 • Current collecting valve 3 flows into _VF . Working oil that flows into the shunt-Atsumariryuben 3 _VF, since entering the head-side oil chamber of the left intermediate portion cylinder 3a via the third intermediate portion line 3h, the rod side oil chamber of the right intermediate unit cylinder 3b, the left and right The intermediate cylinders 3a and 3b operate on the left side. The hydraulic oil pushed out from the rod side oil chamber of the left intermediate cylinder 3a returns to the tank T through the fourth intermediate line 3i and the oil return replenishment line 5.

The hydraulic oil pushed out from the head side oil chamber of the right middle cylinder 3b is a cylinder side line of the first middle line 3c, the front switching valve 2 _V of the front hydraulic circuit 2, and the fourth front line 2f. Since it flows into the head side oil chamber of the left front cylinder 2a through 2f ₁ , the left front cylinder 2a operates on the left side. Of course, the right front cylinder 2b operates to the left by the action of the trapezoidal link 21 shown in FIG. Then, working fluid forced out of the rod side oil chamber of the left front cylinder 2a is a 1R port P _R1 of the pressure-oil switching means 1a via the first front line 2c, also the head side oil chamber of the right front cylinder 2b extruded from the hydraulic pump 22, returns to the 2R port P _R2 of the pressure-oil switching means 1a via the second front line 2d. When the handle of the pressure oil switching means 1a is turned to the right side, as described above, all the cylinders are operated to the left side, so that all the wheels are steered to the right side.

  On the other hand, when the handle of the pressure oil switching means 1a is turned to the left, the hydraulic oil flows in the opposite direction to the above, so the left and right front cylinders 2a and 2b, the left and right intermediate cylinders 3a and 3b, and the left and right rear cylinders 4a and 4b. Operates to the right. In this case, hydraulic oil flows only from the front hydraulic circuit 2 into the head side oil chamber of the right intermediate cylinder 3b, and does not flow into the rod side oil chamber of the left intermediate cylinder 3a. Therefore, the hydraulic oil is supplied from the tank T to the rod side oil chamber of the left intermediate cylinder 3a via the oil return replenishment line 5 and the fourth intermediate line 3i.

The steering of the wheels in the clamp steering mode of the multi-axis vehicle according to the third embodiment of the present invention will be described with reference to FIG. In the clamp steering mode of the multi-axis vehicle according to the third embodiment of the present invention, the left and right wheels of the front steering shaft and the left and right wheels of the intermediate steering shaft and the rear steering shaft are steered to the opposite side. The left and right wheels of the rear steering shaft are steered at a steering angle larger than the steering angle of the left and right wheels of the intermediate steering shaft. In this case, when the steering mode selector switch provided on a driver's seat of the multi-axle vehicle to clamp steering mode, the intermediate portion independent mode switching valve V ₂ is F position by the excitation of the solenoid, the front switching valve 2 _V Is in the G position, the first intermediate selector valve 3 _V1 is in the K position, the second intermediate selector valve 3 _V2 is in the J position, the third intermediate selector valve 3 _V3 is in the I position, and the fourth intermediate selector valve 3 _V4 is switched to the L position. Therefore, all the cylinders are controlled by the hydraulic fluid flowing in the line indicated by the thick line in FIG.

That is, in order to steer the wheels of the front steering shaft to the right, turn off the handle of the pressure-oil switching means 1a to the right, working oil discharged from the 2L port P _L2 of the pressure-oil switching means 1a previous fourth part line 2f IPS side line 2f _2, and flows into the first intermediate portion line 3c of the central hydraulic circuit 3 via the front switching valve _{2 V.} A part of the hydraulic fluid flowing into the first intermediate portion line 3c and flows into the shunt-Atsumariryuben 3 _VF via a bypass line 3j. The remainder of the hydraulic oil that has flowed into the first intermediate line 3c flows into the head side oil chamber of the right intermediate cylinder 3b, so that the right intermediate cylinder 3b operates to the right side and the left intermediate cylinder 3a has a trapezoidal link. In order to operate to the right side by the action, the wheel of the middle layer shaft is steered to the left side. The hydraulic oil pushed out from the rod side oil chamber of the right middle cylinder 3b returns to the tank T. Meanwhile, working fluid forced out of the head-side oil chamber of the left intermediate portion cylinder 3a is merges with actuation flows into the third diversion through an intermediate portion line 3h · Atsumariryuben 3 _VF, flows from the bypass line 3j, through the fourth intermediate portions changeover valve 3 _V4 flows into the second rear line 4e of the rear hydraulic circuit 4.

The hydraulic oil flowing into the second rear line 4e flows into the rod side oil chamber of the left rear cylinder 4a and the head side oil of the right rear cylinder 4b, and the left and right rear cylinders 4a and 4b operate to the right side. The wheels are steered to the left. The hydraulic oil pushed out from the head side oil chamber of the left rear cylinder 4a and the rod side of the right rear cylinder 4b passes through the first rear line 4d, the fourth intermediate switching valve 3 _V4 and the second intermediate line 3d. It flows into the front switching valve 2 _V parts hydraulic circuit 2. Working oil that flows into the front switching valve 2 _V flows into the head-side oil chamber of the left front cylinder 2a via cylinder-side line 2f ₁ of the fourth front line 2f, since the left front cylinder 2a is operated to the left The wheels of the front steering shaft are steered to the right. Of course, the right front cylinder 2b operates to the left side by the trapezoidal link function. Then, working fluid forced out of the rod side oil chamber of the left front cylinder 2a is the first 1R port P _R1 of the pressure-oil switching means 1a via the first front line 2c, also the head side oil right front cylinder 2b extruded hydraulic fluid from the chamber returns to the 2R port P _R2 of the pressure-oil switching means 1a via the second front line 2d.

  Further, when the handle of the pressure oil switching means 1a is turned to the left, the left and right front cylinders 2a, 2b are operated to the right due to the reverse flow of the hydraulic oil, so that the wheels of the front steering shaft are steered to the left. The On the other hand, the left and right rear cylinders 4a and 4b operate on the left side, and the left and right intermediate cylinders 3a and 2b operate on the left side and are steered to the right side opposite to the wheels of the front steering shaft. The hydraulic oil pushed out from the rod side oil chamber of the left middle cylinder 3a returns to the tank T via the fourth middle line 3i.

The single steering of the rear steering shaft for steering only the wheels of the rear steering shaft of the multi-axis vehicle according to the third embodiment of the present invention to the right alone will be described with reference to FIG. The intermediate portion independent mode switching valve V ₂ is F position by the excitation of the solenoid, the first middle switching valve 3 _V1 is K positions, a fourth intermediate portion switching valve 3 _V4 is L position and the directional control valve V ₃ Is switched to the N position. Therefore, the left and right rear cylinders 4a and 4b are operated to the left side by the hydraulic oil flowing in the line indicated by the thick line in FIG.

More specifically, the hydraulic oil supplied from the pressure source P _S, the direction switching valve V _3, the second middle line 3d, and the fourth first rear line of the rear hydraulic circuit 4 through an intermediate portion switching valve 3 _V4 sequentially Flows into 4d. Accordingly, the hydraulic oil that flows into the first rear line 4d flows into the head side oil chamber of the left rear cylinder 4a and the rod side oil chamber of the right rear cylinder 4b, and the left and right rear cylinders 4a and 4b operate to the left. Therefore, the wheel of the rear steering shaft is steered to the right side. Then, the rod-side oil chamber of the left rear portion cylinder 4a, right rear hydraulic fluid forced from the head side chamber of the cylinder 4b and the second rear line 4e, the fourth intermediate portion switching valve 3 _V4, shunt-Atsumariryuben 3 _VF , bypass line 3j, through the directional control valve _{V 3} returns to the tank T.

The single steering of the rear steering shaft for steering only the wheels of the rear steering shaft of the multi-axle vehicle according to Embodiment 3 of the present invention to the left alone will be described with reference to FIG. The intermediate portion independent mode switching valve V ₂ is F position by the excitation of the solenoid, the first middle switching valve 3 _V1 is K positions, a fourth intermediate portion switching valve 3 _V4 is L position, the directional control valve V ₃ Switch to M position. Therefore, the left and right rear cylinders 4a and 4b are actuated to the right by the working oil flowing in the line indicated by the bold line in FIG.

Specifically, the hydraulic oil supplied from the pressure source _{P S,} the direction switching valve _{V 3,} the first middle line 3c, the bypass line 3j, the first middle switching valve _{3 V1,} shunt-Atsumariryuben _{3 VF,} and through the fourth intermediate portions changeover valve 3 _V4 flows into the second rear line 4e of the rear hydraulic circuit 4. Since the hydraulic oil flowing into the second rear line 4e flows into the rod side oil chamber of the left rear cylinder 4a and the head side chamber of the right rear cylinder 4b, the left and right rear cylinders 4a and 4b operate to the right side, The wheel of the steering shaft is steered to the left. Then, after a head-side oil chamber of the left rear portion cylinder 4a, right rear working fluid forced out of the rod side chamber of the cylinder 4b is first rear line 4d, a fourth intermediate portion switching valve 3 _V4, the directional control valve V ₃ Return to tank T.

The single steering of the intermediate steering shaft for steering only the wheels of the intermediate steering shaft of the multi-axle vehicle according to Embodiment 3 of the present invention to the right will be described with reference to FIG. The intermediate portion independent mode switching valve V ₂ is F position by the excitation of the solenoid, and the directional control valve V ₃ is switched to N position. Therefore, the left and right intermediate cylinders 3a and 3b are operated to the left by the hydraulic fluid flowing in the line indicated by the thick line in FIG.

Specifically, the hydraulic oil supplied from the pressure source _{P S,} the direction switching valve _{V 3,} the second middle line 3d, the fourth intermediate portion switching valve _{3 V4,} shunt-Atsumariryuben _{3 VF,} and a third intermediate portion It flows into the head side oil chamber of the left middle cylinder 3a and the rod side oil chamber of the right middle cylinder 3b via the line 3h, and the left and right middle cylinders 3a, 3b are operated to the left side. Steered to.
Then, the rod-side oil chamber of the left intermediate portion cylinders 3a, working fluid forced out of the head-side oil chamber of the right intermediate unit cylinder 3b, the first intermediate portion line 3c, the tank T via the directional control valve V ₃ Return.

The single steering of the intermediate steering shaft for steering only the wheels of the intermediate steering shaft of the multi-axle vehicle according to Embodiment 3 of the present invention to the left alone will be described with reference to FIG. The intermediate portion independent mode switching valve V ₂ is F position by the excitation of the solenoid, and the directional control valve V ₃ is switched to M position. Therefore, the left and right intermediate cylinders 3a and 3b are actuated to the right side by the working oil flowing in the line indicated by the thick line in FIG.

Specifically, the hydraulic oil supplied from the pressure source P _S, the direction switching valve V _3, and the rod-side oil chamber of the left intermediate portion cylinder 3a via the first intermediate portion line 3c, the head side of the right intermediate unit cylinder 3b Since the oil flows into the oil chamber and the left and right intermediate cylinders 3a and 3b operate on the right side, the wheels of the rear steering shaft are steered to the left side. Then, working fluid forced out of the rod side oil chamber of the head-side oil chamber and right intermediate portions cylinder 3b of the left intermediate portion cylinder 3a, the third intermediate portion line 3h, shunt-Atsumariryuben 3 _VF, the fourth intermediate portions It returns to the tank T through the switching valve 3 _V4 , the second intermediate line 3 d and the direction switching valve V ₃ .

  Note that the multi-axle vehicle according to the first to third embodiments of the present invention is merely a specific example, and therefore the form of the multi-axis vehicle according to the present invention is limited by the multi-axis vehicle according to the above-described embodiment. It is not something. Furthermore, design changes and the like within a range not departing from the technical idea of the present invention are free.

1 is a system diagram of a front hydraulic circuit and an intermediate hydraulic circuit of a multi-axis vehicle according to a first embodiment of the present invention. It is typical structure explanatory drawing of the trapezoid link of a multi-axis vehicle. It is explanatory drawing of the steering ratio of the wheel of the front part steering shaft of the multi-axle type vehicle which concerns on Embodiment 1 of this invention, and an intermediate part steering shaft. It is explanatory drawing in the case of steering individually the left and right wheels of the front steering shaft and the intermediate steering shaft of the multi-axle vehicle according to Embodiment 1 of the present invention. FIG. 5 is a system diagram of a front hydraulic circuit and an intermediate hydraulic circuit of a steering control unit of a multi-axis vehicle according to a second embodiment of the present invention. It is a systematic diagram of the steering control means which shows the normal state of the multi-axle vehicle according to Embodiment 3 of the present invention. It is a systematic diagram of the steering control means which shows the club steering state of the multi-axis vehicle which concerns on Embodiment 3 of this invention. It is a systematic diagram of the steering control means which shows the clamp steering state of the multi-axis vehicle which concerns on Embodiment 3 of this invention. It is a systematic diagram of the steering control means showing the rear steering shaft independent (right) steering state of the multi-axis vehicle according to the third embodiment of the present invention. It is a systematic diagram of the steering control means showing the rear steering shaft independent (left) steering state of the multi-axis vehicle according to the third embodiment of the present invention. FIG. 9 is a system diagram of steering control means showing an intermediate part steering shaft independent (right) steering state of a multi-axis vehicle according to a third embodiment of the present invention. It is a systematic diagram of the steering control means showing the intermediate part steering shaft independent (left) steering state of the multi-axle vehicle according to Embodiment 3 of the present invention. FIG. 9 is a hydraulic circuit diagram of a steering device controlled by a steering valve according to a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steering control means 1a ... Pressure oil switching means, 1b ... Handle, 1c ... Mechanical link 2 ... Front hydraulic circuit, 2a ... Left front cylinder, 2b ... Right front cylinder, 2c ... First front line, 2d ... First 2 front line, 2e ... 3rd front line, 2f ... 4th front line, 2f ₁ ... cylinder side line, 2f ₂ ... IPS side line, 2g ... 1st hydraulic oil supply line, 2h ... 2nd hydraulic oil Supply line, 2 _V ... Front switching valve 3 ... Intermediate hydraulic circuit, 3a ... Left intermediate cylinder, 3b ... Right intermediate cylinder, 3c ... First intermediate line, 3d ... Second intermediate line, 3e ... Operation oil supply line, 3f ... first branch line, 3 g ... second branch line, 3h ... third intermediate portion line, 3i ... fourth intermediate portion line, 3j ... bypass line, 3 _{V1 ...} first middle switching valve, 3 _{V2 ...} second middle switching valve, _{3 V} ... third intermediate portion switching valve, 3 _{V4 ...} fourth intermediate portion switching valve, 3 _{VF ...} shunt-Atsumariryuben 4 ... rear hydraulic circuit, 4a ... left rear cylinder, 4b ... right rear cylinder, 4c ... pilot Shikigyakutome Valves, 4d ... first rear line, 4e ... second rear line 5 ... oil return replenishment line, 5a ... oil return line, 5b ... oil replenishment line 6 ... hydraulic oil supply / discharge line, 6a ... pilot check valve 20 ... wheel 21 ... trapezoidal link, 22 ... arm, 23 ... tie rod L 1 _... first link, L 2 _... second link P _{R1 ...} first 1R port, P _{R2 ...} the 2R port, P _{L1 ...} second 1L _{port, P L2} ... 2nd L port, P _S ... pressure source, T ... tank V ₁ ... servo valve, V ₂ ... intermediate independent mode switching valve, V ₃ ... direction switching valve

Claims (3)

  A front hydraulic circuit including a hydraulic line that communicates from the pressure oil switching means to the left front cylinder and the right front cylinder that steer the left and right wheels of the front steering shaft that are synchronously steered by the trapezoidal link and that supplies hydraulic oil; A multi-shaft type equipped with a steering control means comprising an intermediate hydraulic circuit that supplies hydraulic oil to a left intermediate cylinder and a right intermediate cylinder that steer left and right wheels of an intermediate steering shaft that is synchronously steered by a trapezoidal link In the vehicle, a first intermediate line communicating with the rod-side oil chamber of the left intermediate cylinder of the intermediate hydraulic circuit and the head-side oil chamber of the right intermediate cylinder, and the head-side oil chamber and right intermediate of the left intermediate cylinder A hydraulic fluid supply line extending from the first intermediate line and the pressure source to a position where both the first intermediate line and the second intermediate line are blocked, and a second intermediate line communicating with the rod side oil chamber of the cylinder. 4-port 3-position servo that switches the position where the second intermediate line and tank communicate with each other, and the position where the first intermediate line and tank communicate with each other, and the second intermediate line and pressure source communicate with each other. A valve is interposed, a rod of one front cylinder of the left and right front cylinders and a spool of the servo valve by a first link, and a rod of an intermediate cylinder on the side to which the first link is connected; A longitudinal position where the sleeve of the servo valve is connected by a second link, and the first link and the second link have a link ratio corresponding to the steering ratio of the front steering shaft and the intermediate steering shaft. A multi-axis vehicle characterized in that it is rotatably supported by the vehicle.   A position where the first intermediate line and the second intermediate line communicate with each other between the servo valve and the left and right intermediate cylinders of the first intermediate line and the second intermediate line; A first branch line branched from each of the first intermediate line and the second intermediate line, with a four-port two-position intermediate independent mode switching valve for switching to a position for blocking the second intermediate line; The second branch line is configured to communicate with the hydraulic oil supply line via a direction switching valve, and the direction switching valve is configured to shut off the first branch line and the second branch line; The first branch line and the hydraulic oil supply line communicate with each other, the second branch line communicates with the tank, the first branch line communicates with the tank, and the second branch line communicates. Multi-axle vehicle according to claim 1, characterized in that a valve 4-port three-position switching to the position for communicating the hydraulic oil supply line.   The multi-axle vehicle according to claim 1, wherein the pressure source selects and uses the highest pressure of all the hydraulic oil supply lines to the left and right front cylinders.

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