Control valve unit and work vehicle

Abstract

To enable the elimination of operation against a will with a control valve, even if a part of a body of a worker erroneously contacts with an operation tool and the like.SOLUTION: A control valve unit is equipped with manual operation valves 15 and 16 that supply a working fluid of a working fluid channel to a hydraulic actuator, a pilot operation valve that is operated by the pilot pressure of a pilot channel 23 and controls the supplying / discharging of the working fluid of the working fluid channel, and a lock member 31 that engages to an engaging portion Sa of a spool S of the manual operation valves 15 and 16 by the energizing force of an energizing member 32. A lock releasing channel 35 is provided, which moves the lock member 31 to a non-engaging position by the pilot pressure of the pilot channel 23. The lock member 31 engages with the engaging portion Sa to prevent the operation of the spool S when the manual operation valves 15 and 16 are at a non-operating position and the pressure of the lock releasing channel 35 is released.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control valve unit and a work vehicle. [Background technology]

[0002] Taking an example of a front loader that is equipped with a boom cylinder and a bucket cylinder and enables bucket work, as shown in Patent Document 1, there is a type that uses an operating lever that enables manual operation of a boom control valve that controls the boom cylinder and a bucket control valve that controls the bucket cylinder.

[0003] In this patent document, the system is configured such that either the boom control valve or the bucket control valve can be selectively operated by selecting the operating direction of a single operating lever.

[0004] Patent document 2 describes a first control valve that controls the hydraulic oil that extends and retracts the boom cylinder, in which a cylindrical spool is inserted into a through hole in the main body that constitutes the valve, and an operating member such as a lever is connected to the part of the spool that protrudes from the main body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-285564 A [Patent Document 2] Patent Publication No. 2021-107735 Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Document 1, an operating lever for manually operating a control valve that supplies and discharges hydraulic oil to a hydraulic cylinder is disposed near the driver's seat. Also, as described in Patent Document 2, the spool of the control valve may be configured to be directly operated by a lever or the like. Therefore, for example, after work is completed, there is a possibility that a part of the worker's body may accidentally come into contact with the operating lever, causing the control valve to be operated against his or her will.

[0007] Thus, it is necessary to prevent the control valve from being operated against one's will. [Means for solving the problem]

[0008] A characteristic configuration of a control valve unit according to the present invention includes a hydraulic oil flow path to which hydraulic oil is supplied from a hydraulic oil pump, a pilot flow path to which pilot pressure is applied from a pilot oil pump, a manually operated valve that supplies hydraulic oil in the hydraulic oil flow path to a hydraulic actuator by manual operation, a locking member that can be engaged with an engaging portion formed in a spool of the manually operated valve by the biasing force of a biasing member, and an unlocking flow path that moves the locking member to a disengaged position against the biasing force of the biasing member by the pilot pressure of the pilot flow path, and when the manually operated valve is in the disengaged position and the pressure in the locking release flow path is released, the locking member engages with the engaging portion by the biasing force of the biasing member, thereby disabling operation of the spool. a back pressure discharge flow passage that discharges back pressure of the locking member when the locking member is actuated to the disengagement position by the action of a pilot pressure, and the unlocking flow passage and the back pressure discharge flow passage are provided on the same side of the locking member when viewed from a direction perpendicular to a movement direction of the locking member between a position where the locking member engages with the engagement portion and the disengagement position. It is at the point.

[0009] According to this characteristic configuration, for example, when pilot pressure is applied to the pilot flow path from the pilot oil pump, the pilot pressure applied to the unlocking flow path is also maintained at a high value, and the locking member is held in the disengaged position against the biasing force of the biasing member. On the other hand, when the pilot pressure in the pilot flow path is released (including when it drops significantly), for example, as when the pilot oil pump stops, the pilot pressure applied to the unlocking flow path is also released, and when the manually operated valve is in the disengaged position, the locking member engages with the engagement portion of the spool, making it impossible to operate the manually operated valve.

[0010] For example, in a work vehicle equipped with the control valve unit and in which the pilot oil pump is driven by the vehicle's engine or electric motor, when the work is completed, the engine or electric motor stops and the manually operated valve is in a non-operating position (e.g., neutral position), the locking member automatically engages with the engagement portion of the spool, so that the manually operated valve can be maintained in the non-operating position even if part of the worker's body accidentally comes into contact with an operating tool or the like. Therefore, even if a part of the operator's body accidentally comes into contact with an operating tool or the like, the control valve can be prevented from being operated against his or her will. When the locking member is actuated to the disengaged position by the action of the pilot pressure, the back pressure of the locking member is discharged through the back pressure discharge passage, thereby enabling the locking member to be operated smoothly. As an additional configuration to the above configuration, the unlocking flow path and the back pressure discharge flow path may be provided along the spool when viewed from a direction perpendicular to a movement direction of the locking member between the position where it engages with the engagement portion and the disengagement position.

[0011] In addition to the above configuration, a pilot operated valve may be provided that controls the supply and discharge of hydraulic oil in the hydraulic oil passage in response to a pilot pressure applied to the pilot passage.

[0012] The pilot pressure applied to the pilot flow passage enables the pilot operated valve to control the supply and discharge of hydraulic oil to the working flow passage.

[0013] As an additional configuration to the above configuration, a pilot drain passage for discharging pilot oil when the pilot pressure acting on the pilot operated valve is released. The back pressure discharge flow path includes:When the locking member is actuated to the disengaged position by the action of the pilot pressure, the back pressure of the locking member is discharged to the pilot drain passage. You can do that.

[0014] According to this, the pilot pressure of the pilot flow path is applied to the locking member via the unlocking flow path to release the engagement of the locking member, and at the time of release, the back pressure of the locking member is discharged from the back pressure discharge flow path to the pilot drain flow path, thereby allowing the locking member to operate smoothly.

[0015]

[0016]

[0017]

[0018]

[0019] A characteristic configuration of the work vehicle according to the present invention is that it is equipped with a control unit having the above-described configuration, the hydraulic oil pump, and the pilot oil pump.

[0020] According to this characteristic configuration, when pilot pressure is applied from the pilot oil pump to the pilot flow path, the pilot pressure applied to the unlocking flow path is also maintained at a high value, and the locking member is held in the disengaged position against the biasing force of the biasing member. In contrast, when the pilot pressure in the pilot flow path is released (including when it drops significantly), for example, as when the pilot oil pump stops, the pilot pressure applied to the unlocking flow path is also released, and when the manually operated valve is in the disengaged position, the locking member engages with the engagement portion of the spool, making it impossible to operate the manually operated valve. Therefore, even if a part of the worker's body accidentally comes into contact with an operating tool or the like on the work vehicle, the control valve can be prevented from being operated against his or her will.

[0021] As an additional configuration to the above configuration, a unit case may be provided that constitutes the control valve unit, and the hydraulic oil pump and the pilot oil pump may be driven by an engine or an electric motor of the work vehicle.

[0022] According to this, when a work vehicle is equipped with a unit case that constitutes a control valve unit and the pilot oil pump is driven by the vehicle's engine or electric motor, when the work is completed, the engine or electric motor stops and the manually operated valve is in a non-operating position (e.g., neutral position), the locking member automatically engages with the engaging portion of the spool, so that the manually operated valve can be maintained in the non-operating position even if part of the worker's body accidentally comes into contact with an operating tool, etc.

[0023] As an additional configuration to the above configuration, a boom driven by a boom cylinder as the hydraulic actuator and a bucket driven by a bucket cylinder as the hydraulic actuator are provided, and a hydraulic actuator for controlling the boom cylinder is provided. The above A boom control valve as a manually operated valve and a bucket cylinder control valve as a manually operated valve The above The hydraulic machine may further include a bucket control valve as a manually operated valve, the boom control valve, and an operating tool for manually operating the bucket control valve.

[0024] According to this, when the pilot pressure in the pilot flow path is released and the operating tool is in a non-operated state, the spool of the boom control valve and the spool of the bucket control valve are disabled, thereby eliminating the inconvenience of the control valve being operated even if part of the worker's body comes into contact with the operating tool. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a side view showing a skid steer loader. [Diagram 2] FIG. 4 is a hydraulic circuit diagram of the control valve unit. [Diagram 3] FIG. 4 is a cross-sectional view of the locking mechanism in a locked state. [Figure 4]FIG. 4 is a cross-sectional view of the locking mechanism in an unlocked state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Basic configuration] 1 shows a skid steer loader A as an example of a work vehicle. This skid steer loader A has an engine E disposed at the rear of a vehicle body 3 having a pair of left and right front wheels 1 and a pair of left and right rear wheels 2, and a cabin 4 disposed at the front of the vehicle body 3.

[0027] This skid steer loader A is equipped with a pair of left and right booms 6, a bucket 7 supported on the front ends of the booms 6, left and right boom cylinders 11 (an example of a hydraulic actuator) that drive the boom 6, and left and right bucket cylinders 12 (an example of a hydraulic actuator) that set the attitude of the bucket 7. Also, equipped inside the cabin 4 are a driver's seat 8, and an operating lever 9 (an example of an operating tool) that controls the boom cylinders 11 and bucket cylinders 12.

[0028] The rear end portions of the left and right booms 6 are supported so as to be freely swingable on the rear end portion of the vehicle body 3 via a pair of front and rear link members 5. The front ends of the left and right booms 6 are raised by the extension operation of the boom cylinders 11, and lowered by the contraction operation of the boom cylinders 11.

[0029] The bucket 7 is supported so as to be freely swingable about a support shaft 13 that is in a horizontal position relative to the front end of the boom 6, and its position about the support shaft 13 is determined by the extension and contraction of the bucket cylinder 12.

[0030] [Control valve unit] As shown in FIG. 2, the control valve unit B is provided on the vehicle body 3, and includes a boom control valve 15 (an example of a manually operated valve), a bucket control valve 16 (an example of a manually operated valve), and a pilot operated valve 17 inside a unit case Bc.

[0031] The control valve unit B mechanically operates the boom control valve 15 and the bucket control valve 16 in conjunction with the operation of the operating lever 9, thereby supplying and discharging hydraulic oil to the boom cylinder 11 and the bucket cylinder 12, thereby enabling the boom cylinder 11 and the bucket cylinder 12 to be driven separately.

[0032] Moreover, the boom control valve 15 and the bucket control valve 16 are configured to hold the spool S in a neutral position (an example of a non-operating position) as shown in FIG. 2 when the operating lever 9 is not operated.

[0033] The pilot-operated valve 17 is operated by setting a pilot pressure controlled by a pair of electromagnetic proportional valves 18, and enables the supply and discharge of hydraulic oil via a dedicated service port 19 formed in the unit case Bc when a new hydraulic cylinder or the like is installed in the vehicle body 3.

[0034] Furthermore, the control valve unit B is provided with a lock mechanism L that holds the boom control valve 15 and the bucket control valve 16 in their respective neutral positions when the engine E is stopped.

[0035] By providing such a locking mechanism L, even if part of the worker's body accidentally comes into contact with an operating tool after work is completed, the phenomenon in which the boom control valve 15 or the bucket control valve 16 is operated against his or her will is eliminated, and the phenomenon in which the boom 6 or the bucket 7 is operated against his or her will when work is subsequently resumed can be prevented.

[0036] Incidentally, as one example of the operation form of the operating lever 9, it can be considered that it is supported so as to be operable in the forward / backward and left / right directions, and by selecting between these operations, the lifting and lowering control of the boom 6 and the attitude control of the bucket 7 can be performed.

[0037] 2, the control valve unit B includes a hydraulic oil passage 21, a hydraulic oil drain passage 22, a pilot passage 23, and a pilot drain passage 24. In this control valve unit B, hydraulic oil is supplied to the hydraulic oil passage 21 from a hydraulic oil pump 25 driven by the engine E, and pilot pressure is applied to the pilot passage 23 from a pilot oil pump 26 driven by the engine E.

[0038] [Control valve unit: lock mechanism] As shown in FIGS. 3 and 4, the spool S is accommodated in a valve housing 30 which functions as a unit case Bc accommodating the spool C so as to be movable in a direction along the longitudinal direction of the spool S.

[0039] As shown in Figures 3 and 4, the locking mechanism L includes an engagement portion Sa formed by reducing the diameter of a portion of the spool S of the boom control valve 15 and the bucket control valve 16, a locking member 31 that can be engaged and disengaged separately from each of the engagement portions Sa, and a compression coil type spring 32 (an example of a biasing member) that biases the locking member 31 in the engagement direction.

[0040] The locking member 31 is accommodated in the valve housing 30 so as to be movable in a direction perpendicular to the movement direction of the spool S. The locking member 31 includes a shaft-shaped portion 31a that is engageable with and disengageable from the engagement portion Sa and is fitted into the hole-shaped portion 30a of the valve housing 30, a large-diameter portion 31b that is larger in diameter than the shaft-shaped portion 31a and is fitted into the cylinder-shaped portion 30b of the valve housing 30, and a spring receiving portion 31c that is larger in diameter than the large-diameter portion 31b and is accommodated in the spring accommodating space 30c.

[0041] In this locking mechanism L, a seal ring 33 is provided on the inner circumference of the hole-shaped portion 30a to suppress the flow of pilot oil around the inner circumference of the hole-shaped portion 30a, and the inner circumference of the cylindrical portion 30b and the outer circumference of the large diameter portion 31b are brought into close contact with each other to suppress the flow of pilot oil at this close contact area.

[0042] Furthermore, a gap through which pilot oil can flow is formed between the inner periphery of the spring accommodating space 30c and the outer periphery of the spring receiving portion 31c.

[0043] The valve housing 30 forms an unlocking passage 35 at the boundary between the hole-shaped portion 30a and the cylindrical portion 30b, through which pilot pressure from the pilot passage 23 is applied, and forms a backpressure discharge passage 36 between the outer periphery of the spring receiving portion 31c and the gap through which pilot oil can flow, which connects the gap to the pilot drain passage 24.

[0044] The locking mechanism L is configured such that the protruding position is determined by the biasing force of the spring 32 acting on the spring receiving portion 31c, causing the end of the spring receiving portion 31c to abut against the boundary between the cylindrical portion 30b and the spring accommodating space 30c.

[0045] [Operation of the locking mechanism] Because the lock mechanism L is configured in this manner, when the engine E is operating, the pilot pressure in the pilot flow path 23 increases, and the pilot pressure in the unlocking flow path 35 increases, so that the shaft-shaped portion 31a of the locking member 31 disengages from the engaging portion Sa of the spool S, as shown in FIG. 4, and is held in an unlocked position spaced outward from the outer periphery of the spool S, making it possible to operate the boom control valve 15 and the bucket control valve 16.

[0046] When the pilot pressure in the unlocking passage 35 increases and the locking member 31 moves to the unlocking position, the pilot oil in the spring accommodating space 30c is discharged to the pilot drain passage 24 via the back pressure discharge passage 36.

[0047] In contrast, when the engine E is stopped, such as after bucket work is completed, the pilot pressure in the pilot passage 23 is released (greatly reduced), and when the pilot pressure in the unlocking passage 35 decreases, the locking member 31 protrudes due to the biasing force of the spring 32.

[0048] As a result of the locking member 31 protruding in this manner, the shaft-shaped portion 31a reaches a state in which it engages with the engaging portion Sa, as shown in Fig. 3. As a result, when the engine E is stopped, the locking mechanism L is transitioned to a locked state, and the biasing force of the spring 32 disables operation of the boom control valve 15 and the bucket control valve 16, without the need for manual operation of the locking mechanism L.

[0049] As a result, the boom control valve 15 and the bucket control valve 16, which serve as manually operated valves, are maintained in a non-operated position (for example, a neutral position), and even if part of the operator's body accidentally comes into contact with the operating lever 9, the boom control valve 15 and the bucket control valve 16 are maintained in the non-operated position, and when the engine E is started thereafter, the inconvenience of the boom 6 and the bucket 7 being operated against one's will can be eliminated.

[0050] [Another embodiment] The present invention may be configured as follows other than the above-described embodiment (common numbers and symbols as in the embodiment are used to designate components having the same functions as in the embodiment).

[0051] (a) In a work vehicle configured so that all systems of the vehicle body 3 are stopped when work is completed, the hydraulic oil pump 25 and pilot oil pump 26 are driven by electric motors.

[0052] Even if the lock mechanism L is configured to be driven by an electric motor instead of an engine E as in this alternative embodiment (a), the electric motor can be stopped when the work is completed, thereby making it possible to transition the lock mechanism L to a locked state.

[0053] (b) The work vehicle is not limited to the skid steer loader A, but may be a small loader or a vehicle configured to have a unit having a boom 6 and a bucket 7 on the vehicle body 3 to enable bucket work, such as a tractor.

[0054] (c) It is also possible to form a radially penetrating through hole (an example of an engagement portion Sa) in the spool S of the manually operated valve, and configure the locking mechanism L so as to disable operation of the spool S by inserting a part of the locking member 31 into the through hole using the biasing force of the spring 32.

[0055] (d) The pilot operated valve 17 may be provided outside the control valve unit B, and the pilot flow path 23 and the back pressure discharge flow path 36 provided in the control valve unit B may be connected to a pilot oil supply path and a drain oil path, respectively, for the pilot operated valve 17. Alternatively, the pilot operated valve 17 may be omitted, and the pilot flow path 23 and the back pressure discharge flow path 36 provided in the control valve unit B may be connected to the pilot oil pump 26 and the hydraulic oil tank (not shown), respectively. [Industrial Applicability]

[0056] The present invention can be used in a control valve unit that controls a hydraulic actuator and in a work vehicle. [Explanation of symbols]

[0057] 4 Engine 6. Boom 7. Bucket 9 Operating lever (operating tool) 11 Boom cylinder (hydraulic actuator) 12 Bucket cylinder (hydraulic actuator) 15 Boom control valve (manually operated valve) 16 Bucket control valve (manually operated valve) 17 Pilot Operated Valve 21 Hydraulic oil flow path 23 Pilot Channel 24 Pilot drain passage 25 Hydraulic Oil Pump 26 Pilot oil pump 31 Locking member 32 Spring (biasing member) 35 Unlocking channel 36 Back pressure exhaust flow path A Skid steer loader (work vehicle) B Control valve unit Bc unit case E-Engine S-spool Sa Engagement part

Claims

1. a hydraulic oil flow path to which hydraulic oil is supplied from a hydraulic oil pump; a pilot flow passage to which a pilot pressure is applied from a pilot oil pump; a manually operated valve that is manually operated to supply hydraulic oil from the hydraulic oil passage to a hydraulic actuator; a locking member that can be engaged with an engaging portion formed on a spool of the manually operated valve by a biasing force of a biasing member; an unlocking flow path that moves the locking member to a disengaged position against the biasing force of the biasing member by a pilot pressure of the pilot flow path, when the manually operated valve is in a non-operated position and the pressure in the unlocking flow path is released, the locking member engages with the engaging portion by the biasing force of the biasing member, thereby disabling operation of the spool, a back pressure discharge passage for discharging back pressure of the locking member when the locking member is actuated to the disengaged position by the action of a pilot pressure, a control valve unit in which the unlocking flow path and the back pressure discharge flow path are provided on the same side of the locking member when viewed in a direction perpendicular to a movement direction of the locking member between a position where it engages with the engagement portion and the disengagement position.

2. A control valve unit as described in claim 1, wherein, when viewed from a direction perpendicular to the movement direction of the locking member between the position where it engages with the engaging portion and the disengagement position, the unlocking flow path and the back pressure discharge flow path are arranged along the spool.

3. 3. The control valve unit according to claim 1, further comprising a pilot operated valve that controls the supply and discharge of hydraulic oil in the hydraulic oil passage in response to a pilot pressure applied to the pilot passage.

4. a pilot drain passage for discharging pilot oil when a pilot pressure acting on the pilot operated valve is released; 4. The control valve unit according to claim 3, wherein the back pressure discharge passage discharges the back pressure of the locking member to the pilot drain passage when the locking member is actuated to the disengaged position by the action of a pilot pressure.

5. A work vehicle comprising the control valve unit according to any one of claims 1 to 4, the hydraulic oil pump, and the pilot oil pump.

6. 6. A work vehicle according to claim 5, further comprising a unit case that constitutes the control valve unit, and wherein the hydraulic oil pump and the pilot oil pump are driven by an engine or an electric motor of the work vehicle.

7. The hydraulic actuator includes a boom that is driven by a boom cylinder, and a bucket that is driven by a bucket cylinder, 7. The work vehicle according to claim 5 or 6, further comprising: a boom control valve as the manually operated valve that controls the boom cylinder, a bucket control valve as the manually operated valve that controls the bucket cylinder, and operating tools for manually operating the boom control valve and the bucket control valve.

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