CN101516715B - Steering system for working vehicle - Google Patents

Steering system for working vehicle Download PDF

Info

Publication number
CN101516715B
CN101516715B CN2007800345490A CN200780034549A CN101516715B CN 101516715 B CN101516715 B CN 101516715B CN 2007800345490 A CN2007800345490 A CN 2007800345490A CN 200780034549 A CN200780034549 A CN 200780034549A CN 101516715 B CN101516715 B CN 101516715B
Authority
CN
China
Prior art keywords
valve
pressure
control
working rig
hydraulic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN2007800345490A
Other languages
Chinese (zh)
Other versions
CN101516715A (en
Inventor
中村和则
中村刚志
木原光男
东宏行
岛津淳志
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Construction Machinery Co Ltd
Original Assignee
Hitachi Construction Machinery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2006350432A external-priority patent/JP4993575B2/en
Application filed by Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Priority claimed from PCT/JP2007/075033 external-priority patent/WO2008081843A1/en
Publication of CN101516715A publication Critical patent/CN101516715A/en
Application granted granted Critical
Publication of CN101516715B publication Critical patent/CN101516715B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Operation Control Of Excavators (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Power Steering Mechanism (AREA)

Abstract

The present invention provides a hydraulic steering system for a working vehicle, wherein a hydraulic steering unit (5) produces, based on pressurized oil from a pilot pump (13), a control pressure corresponding to the amount and direction of rotation of a steering wheel (109), and a signal from pressure sensors (6a, 6b), which detect the control pressure, and a signal from a front operation detection device (31) are inputted into a controller (132). A controller (32) and solenoid valves (33a, 33b) increase the stroke of a steering valve (4) with an increase in control pressures detected by the pressure sensors (6a, 6b), and when the controller and the solenoid valves detect operation of a front working machine, they perform control so that the stroke of the steering valve (4) is greater than the case where they do not detect operation of the front working machine. The speed of steering wheel is set to an optimum value both when traveling and the front working machine are operated at the same time and when only traveling is operated. By this, sufficient work efficiency and safety are secured and operability is enhanced.

Description

The steering swivel system of working truck
Technical field
The present invention relates to the steering swivel system of working trucks such as wheel type loader.
Background technology
The steering swivel system of working trucks such as wheel type loader has: Hydraulic Pump, the hydraulic steering cylinder that is driven by the hydraulic oil from the ejection of this Hydraulic Pump, to the direction of the hydraulic oil supplied with to hydraulic steering cylinder from Hydraulic Pump and the convertible valve that flow is controlled; Hand of rotation and rotation amount according to bearing circle (handle) switch convertible valve, thereby hydraulic steering cylinder is carried out drive controlling.Under this situation, adopt the fluid-link steering unit that is known as ORBITROL (trade name) to implement according to the switching that the hand of rotation of bearing circle (handle) and rotation amount carry out convertible valve.Here, this fluid-link steering unit has hydraulic valve and the HM Hydraulic Motor that the rotary manipulation with bearing circle moves linkedly, produces the hydraulic pressure with this rotation amount and hand of rotation corresponding discharge.
In the steering swivel system of such working truck, usually with the fluid-link steering configuration of cells on major loop, direction of passage dish operation convertible valve, and hydraulic steering cylinder carried out drive controlling.Under this situation, the hydraulic valve of fluid-link steering unit disposes as convertible valve, and the hydraulic pressure that hydraulic valve units produces directly is imported into hydraulic steering cylinder.
Concerning the steering swivel system of this common working truck, known the fluid-link steering unit is used as the operating system of convertible valve, can be easily the rotary manipulation of travel direction dish (for example patent documentation 1) (through less power).In this steering swivel system, adopt pioneer pump as hydraulic power source, the hydraulic pressure switching part (compression zone) of the hydraulic pilot convertible valve that will produce by the fluid-link steering unit, thus convertible valve is switched.In convertible valve, have and be used for converting the hydraulic pressure that imports from the fluid-link steering unit to throttling path that convertible valve switches the control presssure of usefulness.
On the other hand, known a kind of structure, the operating system of convertible valve is made up of the electricity that comprises controller and electromagnetic valve/hydraulic steering unit, carries out the switching (for example patent documentation 2) of convertible valve with the mode of electricity/hydraulic pressure.In this steering swivel system, through the rotary manipulation angle (steering angle) of potentiometer detection bearing circle, and with this detected value input controller.Controller is to electromagnetic valve output and the cooresponding command signal of this detected value (electric signal), and electromagnetic valve is exported and the cooresponding control presssure of this command signal.This control presssure is imported into the hydraulic pressure switching part (compression zone) of convertible valve, and convertible valve is switched.
In addition; In the steering swivel system of patent documentation 2 records; To multiple type be set in the controller with respect to the gain (command signal/steering angle) of the command signal of steering angle detected value in advance, change-over switch operated through the operator, can be from wherein selecting a gain.Thus; Can be adjusted to turning velocity rotary manipulation, wheel (actuating speed of hydraulic steering cylinder) when being suitable for going and during actual job any one with respect to bearing circle, can be respectively in motion or obtain best steering operation property during actual job.In addition, also proposed a kind of variation, the speed sensor that detects moving velocity promptly has been set, command signal has been changed according to moving velocity.
Patent documentation 1: real the opening of Japan put down the 1-154974 communique
Patent documentation 2: japanese kokai publication hei 10-45014 communique
When working trucks such as wheel type loader carry out operation, a kind of operation of working rig before the operation while going is arranged.As one of which example, the digging operation of the mound that carries out through wheel type loader etc. is arranged.In this operation, vehicle body is advanced, scraper bowl is pushed against on the mound excavates, after the excavation, scraper bowl (excavation sand) limit rising edge is retreated, change vehicle body towards.Then, vehicle body is moved, and on truck etc., put soil through going separately.
Yet,,, cause tired reason so if the turning velocity of wheel is slow with respect to the rotary manipulation of bearing circle, the operator can pay close attention to steering operation because this operation is operation when going with preceding working rig.Therefore, under this situation, preferably the rotary manipulation with respect to bearing circle accelerates the turning velocity of wheel, thus, can reduce operator's fatigue, improves operating efficiency.And in going separately, the turning velocity of wheel is accelerated with respect to the rotary manipulation of bearing circle, then safety is higher.
In the steering swivel system of the working truck that patent documentation 1 is put down in writing; Owing to can not change variation ratio with respect to turning velocity rotary manipulation, wheel of bearing circle, thus go with preceding working rig in operation can not obtain best wheel steering speed with each stage of going separately.
In the steering swivel system of the working truck that patent documentation 2 is put down in writing; Owing to can change gain (command signal/steering angle) with respect to the command signal of steering angle detected value through the operation change-over switch, thus can be respectively go with preceding working rig in operation obtain best wheel steering speed with each stage of going separately.But; From go with preceding working rig in the operation (for example digging operation) of operation transform to separately and go (for example to putting the mobile of soil point) when dividing a word with a hyphen at the end of a line; Or when transforming to the operation of operation when going from going separately with preceding working rig; Each operator need operate change-over switch and change gain, extremely trouble.
Summary of the invention
The object of the present invention is to provide a kind of steering swivel system of working truck; Go at the same time respectively and operate before operation and each stage of going separately of working rig; Make wheel steering speed become best value with respect to the rotary manipulation of bearing circle; Can guarantee operating efficiency and safety, and operability is good.
(1) to achieve these goals, the hydrostatic steering system of working truck of the present invention has: Hydraulic Pump; Hydraulic steering cylinder by the hydraulic oil driving that sprays from this Hydraulic Pump; To the direction of the hydraulic oil supplied with to above-mentioned hydraulic steering cylinder from above-mentioned Hydraulic Pump and the convertible valve that flow is controlled; Bearing circle by operator's rotary manipulation.Rotary manipulation according to above-mentioned bearing circle switches above-mentioned convertible valve, and the above-mentioned hydraulic steering cylinder of drive controlling.Wherein, this steering swivel system also has: the preceding operation machine operation testing agency of serviceability that is used to detect the preceding working rig of the body forward structure that is arranged on above-mentioned working truck; Based on the rotary manipulation of above-mentioned bearing circle and by operation machine operation testing agency before above-mentioned detect above-mentioned before the serviceability of working rig to the switching direction of above-mentioned convertible valve and the steering operation control mechanism of controlling through flow.
In the present invention who constitutes like this, operation machine operation testing agency and steering operation control mechanism before being provided with are based on the rotary manipulation of bearing circle with by the serviceability of the detected preceding working rig of preceding operation machine operation testing agency; Control to the switching direction of convertible valve with through flow, thus, go at the same time and operate before in the operation of working rig; When before operation, carrying out steering operation during working rig; Control so that increase during the operation of working rig before the passing through throughput ratio and do not detect of convertible valve, thus, owing to accelerate with respect to the wheel steering speed of the rotary manipulation of bearing circle; Can easily switch in the operation of working rig so go at the same time with before operating and to turn to; Thus, can reduce operator's fatigue, improve operating efficiency.
And before not detecting during the operation of working rig; Control so that few during the operation of working rig before the passing through throughput ratio and detect of convertible valve; Thus; During steering operation in going separately, since slack-off with respect to the wheel steering speed of the rotary manipulation of bearing circle, so improved safety.
In addition, if working rig before the operation then owing to automatically change wheel steering speed, so need not operator's operation, can access good operability.
Like this; The operation of the present invention's working rig before going simultaneously respectively and operating and each stage of going separately, can make wheel steering speed become best value with respect to the rotary manipulation of bearing circle; Operating efficiency and safety can be guaranteed, and good operability can be accessed.
(2) in above-mentioned (1); Preferably; Above-mentioned steering operation control mechanism has: the fluid-link steering unit; Itself and above-mentioned bearing circle link, and the rotary manipulation through this bearing circle moves, and produce rotation amount and hand of rotation the corresponding the 1st and the 2nd control presssure with above-mentioned bearing circle based on the hydraulic oil of guide's hydraulic power source; The the 1st and the 2nd pressure sensor, it detects the 1st and the 2nd control presssure that is produced by above-mentioned fluid-link steering unit respectively; First control mechanism, its based on the 1st and the 2nd control presssure that detects by the above-mentioned the 1st and the 2nd pressure sensor and by operation machine operation testing agency before above-mentioned detect above-mentioned before the serviceability of working rig, the stroke of above-mentioned convertible valve is controlled.
Thus, because according to the rotary manipulation of bearing circle and the serviceability of preceding working rig, the stroke of control convertible valve; And the control convertible valve pass through flow; Operation and each stage of going separately of working rig can make wheel steering speed become best value with respect to the rotary manipulation of bearing circle so go at the same time respectively as described above and before operating; Operating efficiency and safety can be guaranteed, and good operability can be accessed.
In addition, owing to constitute the rotary manipulation of direction of passage dish the fluid-link steering unit is moved, and switch convertible valve, so can be with the rotary manipulation of less power travel direction dish based on the 1st and the 2nd control presssure that produces by the fluid-link steering unit.
(3) in above-mentioned (2); For example, above-mentioned first control mechanism is controlled as follows, along with being increased by the above-mentioned the 1st and the 2nd pressure sensor difference the detected the 1st and the 2nd control presssure; Make the stroke of above-mentioned convertible valve become big; And, when detect through operation machine operation testing agency before above-mentioned above-mentioned before during the operation of working rig, big when making the operation of stroke above-mentioned preceding working rig of above-mentioned convertible valve than not detecting.
Thus, as stated, go at the same time respectively and operate before operation and each stage of going separately of working rig, can make wheel steering speed become best value with respect to the rotary manipulation of bearing circle, can guarantee operating efficiency and safety.
(4) in above-mentioned (2); Above-mentioned first control mechanism is controlled as follows; Along with the 1st and the 2nd control presssure that is detected respectively by the above-mentioned the 1st and the 2nd pressure sensor increases, make the stroke of above-mentioned convertible valve become big, and; When detect through operation machine operation testing agency before above-mentioned above-mentioned before during the bigger operation of the action of working rig, big when making the bigger operation of the action of stroke above-mentioned preceding working rig of above-mentioned convertible valve than not detecting.
Thus; In time go at the same time and operate before during the operation of working rig; The action of working rig is less and when needing prudent microoperation operation before carrying out; Owing to control the stroke of convertible valve less, thus can be really and carry out the microoperation operation exactly, can prevent that in the past drop Loaded goods and vehicle body action of working rig is disorderly.And during the common operation that the action of working rig is bigger before carrying out; Owing to control the stroke of convertible valve bigger, turn to so easily switch during the operation of working rig before can going at the same time and operate, thus; Can alleviate operator's fatigue, improve operating efficiency.
(5) in above-mentioned (2)～(4), preferably, above-mentioned convertible valve has: as the valve plunger of valve plug; The the 1st and the 2nd compression zone, it is positioned at the two ends of this valve plunger, and is imported into driving pressure respectively, correspondingly drives above-mentioned valve plunger and above-mentioned stroke is changed with this driving pressure.Above-mentioned first control mechanism has: the 1st and the 2nd electromagnetic valve, and itself and the corresponding setting respectively of the above-mentioned the 1st and the 2nd compression zone move through control current, and output and this control current corresponding driving pressure; Controller is imported the detected value of the above-mentioned the 1st and the 2nd pressure sensor and preceding operation machine operation testing agency, and based on the calculating that these detected values are stipulated, is exported above-mentioned control current to the above-mentioned the 1st and the 2nd electromagnetic valve.
Thus, the serviceability of the preceding working rig that first control mechanism can detect based on the 1st and the 2nd control presssure that is produced by the fluid-link steering unit with by preceding operation machine operation testing agency is controlled the stroke of convertible valve.
(6) in addition, in above-mentioned (5), preferably, above-mentioned controller has: the 1st computing mechanism, be used to calculate the 1st target drives pressure, and the 1st target drives pressure carries out along with the increase of the control presssure that detects through above-mentioned the 1st pressure sensor increases; The 2nd computing mechanism is used to calculate the 2nd target drives pressure, and the 2nd target drives pressure is along with the increase of the control presssure that detects through above-mentioned the 2nd pressure sensor increases; The 3rd computing mechanism; When detecting the operation of above-mentioned preceding working rig through operation machine operation testing agency before above-mentioned; To the above-mentioned the 1st and the 2nd target drives pressure revise so that its become than detect above-mentioned before big value during the operation of working rig; Export above-mentioned control current to the above-mentioned the 1st and the 2nd electromagnetic valve, to obtain the 1st and the 2nd target drives pressure by above-mentioned the 3rd computing mechanism correction.
Thus; First control mechanism makes the stroke of convertible valve become big along with the increase of the 1st and the 2nd control presssure that is detected respectively by the 1st and the 2nd pressure sensor; And; Before being detected by preceding operation machine operation testing agency during the operation of working rig, the stroke that can control convertible valve is big when making it than the operation of working rig before not detecting.
(7) in addition; In above-mentioned (1), preferably, also has sequence valve; It has and is configured in set mechanism between above-mentioned Hydraulic Pump and the above-mentioned convertible valve and front and back pressure differential expected value that be used to set above-mentioned convertible valve; Make the front and back pressure reduction of above-mentioned convertible valve remain on above-mentioned expected value through control, can the hydraulic oil from the ejection of above-mentioned Hydraulic Pump preferentially be supplied to above-mentioned hydraulic steering cylinder, and residual flow is supplied to the operation that drives working rig use hydraulic circuit; Above-mentioned steering operation control mechanism has: the fluid-link steering unit; Itself and above-mentioned bearing circle link, and move through the rotary manipulation of this bearing circle, based on the hydraulic oil generation of guide's hydraulic power source and the rotation amount and the hand of rotation control corresponding pressure of above-mentioned bearing circle; Guide's oil circuit, it will import the compression zone of above-mentioned convertible valve by the control presssure that above-mentioned fluid-link steering unit produces and above-mentioned convertible valve will be switched; Second control mechanism, its according to detect by operation machine operation testing agency before above-mentioned above-mentioned before the serviceability of working rig the front and back pressure differential expected value of the above-mentioned convertible valve set by the set mechanism of said sequence valve is changed.
Like this, change through front and back pressure differential expected value, according to the serviceability of preceding working rig the convertible valve set by the set mechanism of sequence valve; The front and back pressure reduction of convertible valve changes, convertible valve pass through the flow Be Controlled, therefore; As stated; Go at the same time respectively and operate before operation and each stage of going separately of working rig, can make wheel steering speed become best value with respect to the rotary manipulation of bearing circle; Operating efficiency and safety can be guaranteed, and good operability can be obtained.
In addition; Since with the blocked operation of the corresponding convertible valve of rotary manipulation of bearing circle be to carry out with the mode of hydraulic pressure through the fluid-link steering unit; And; With the control of passing through flow of the corresponding convertible valve of serviceability of preceding working rig is to carry out through the front and back pressure differential control based on the convertible valve of sequence valve, therefore, just in case on as the control mechanism of unique electric system et out of order; Also can move the handling maneuver of vehicle, can guarantee higher safety through the fluid-link steering unit.
And, owing to the blocked operation with the corresponding convertible valve of rotary manipulation of bearing circle is that the operating portion that the control presssure that is produced by the fluid-link steering unit imports convertible valve is carried out, therefore, can be with the rotary manipulation of less power travel direction dish.
(8) in above-mentioned (7); For example; Detect by operation machine operation testing agency before above-mentioned above-mentioned before during the operation of working rig, above-mentioned second control mechanism changes above-mentioned expected value so that big during by the operation of set mechanism target value set above-mentioned preceding working rig than not detecting of said sequence valve.
Thus, as stated, go at the same time respectively and operate before operation and each stage of going separately of working rig, can make wheel steering speed become best value with respect to the rotary manipulation of bearing circle, can guarantee operating efficiency and safety.
(9) in above-mentioned (7); Detect by operation machine operation testing agency before above-mentioned above-mentioned before during the bigger operation of the action of working rig, above-mentioned second control mechanism changes above-mentioned expected value so that big during by the bigger operation of the action of set mechanism target value set above-mentioned preceding working rig than not detecting of said sequence valve.
Thus; Even go at the same time and before operating during the operation of working rig; Before carrying out the action of working rig less, when needing prudent microoperation operation, owing to control the front and back pressure reduction of convertible valve less, therefore; Can be really and carry out the microoperation operation exactly, can prevent that in the past drop goods and vehicle body action of working rig is disorderly.And during the common operation that the action of working rig is bigger before carrying out; Owing to control the front and back pressure reduction of convertible valve bigger, therefore, go at the same time and operate before can easily switch during the operation of working rig and turn to; Can alleviate operator's fatigue thus, improve operating efficiency.
(10) in addition, in above-mentioned (7), preferably, above-mentioned second control mechanism has: electromagnetic valve, move through control current, and output and this control current control corresponding pressure; Expected value change control presssure compression zone is located on the said sequence valve, according to the above-mentioned control presssure of above-mentioned electromagnetic valve output to changing by above-mentioned set mechanism target value set; Controller; Import the detected value of above-mentioned preceding operation machine operation testing agency; And based on this detected value calculate with above-mentioned before the serviceability of working rig be worth accordingly; Export above-mentioned control current to above-mentioned electromagnetic valve, be worth accordingly so that the above-mentioned expected value of being set by above-mentioned set mechanism changes to this serviceability with above-mentioned preceding working rig.
Thus, second control mechanism can change according to the detected value of the preceding operation machine operation testing agency front and back pressure differential expected value to the convertible valve set by the set mechanism of sequence valve.
The effect of invention
According to the present invention; Go at the same time respectively and operate before operation and each stage of going separately of working rig, can make wheel steering speed become best value with respect to the rotary manipulation of bearing circle; Operating efficiency and safety can be guaranteed, and good operability can be obtained.
In addition, according to the present invention, can access good operability through the rotary manipulation of less power travel direction dish.
And, according to the present invention, just in case the electric system et out of order, also can positively move the handling maneuver of vehicle, can guarantee higher safety.
Description of drawings
Fig. 1 is the figure as the outward appearance of an example expression wheel type loader of using working truck of the present invention.
Fig. 2 is the figure of steering swivel system of the working truck of expression an embodiment of the invention.
Fig. 3 is the figure of an example of operation detection device before at length representing.
Fig. 4 is the functional block diagram of the contents processing of expression controller.
Fig. 5 is the functional block diagram of the contents processing of the controller in the steering swivel system of working truck of expression the 2nd embodiment of the present invention.
Fig. 6 is the figure of steering swivel system of the working truck of expression the 3rd embodiment of the present invention.
Fig. 7 is the functional block diagram of the contents processing of expression controller.
Fig. 8 is the functional block diagram of the contents processing of the controller in the steering swivel system of working truck of expression the 4th embodiment of the present invention.
Description of reference numerals
1 driving engine
2 Hydraulic Pumps
The 2a variable capacity control
4 convertible valves
5 steering units
6a, 6b pressure sensor
7,7A sequence valve
The 7a ingress port
7b the 1st outlet port
7c the 2nd outlet port
11 calibrate valves
12 gerotor pumps
17a, 17b oil circuit
18a, 18b flow regulating valve
24a, 24b compression zone
The 24c compression zone
25 springs
26a, 26b activate oil circuit
Operation detection device before 31
32 controllers
32a the 1st basic driver calculation of pressure portion
32b the 2nd basic driver calculation of pressure portion
32c, 32Ac coefficient of correction calculating part
32d the 1st target drives calculation of pressure portion
32e the 2nd target drives calculation of pressure portion
32f the 1st control current calculating part
32g the 2nd control current calculating part
33a, 33b electromagnetic valve
45,46,47 reciprocable valve
48 pressure sensors
100 wheel type loaders
101 body forward structures
102 body tails
103a, 103b hydraulic steering cylinder
Working rig before 104
106 operator'ies compartment
107 trailing wheels
108 driver's seats
109 bearing circle
110 function lever apparatus
111 scraper bowls
112 lift arms
113 scraper bowl hydraulic actuating cylinders
114 arm hydraulic cylinders
Hydraulic circuit is used in 121 operations
131a, 131b guide's oil circuit
132 controllers
132a sequence valve setting pressure calculating part
132b electromagnetic valve delivery pressure calculating part
132c control current calculating part
The specific embodiment
Below, with reference to accompanying drawing embodiment of the present invention is described.
Fig. 1 is the figure as the outward appearance of an example expression wheel type loader of using working truck of the present invention.
In Fig. 1; 100 expression wheel type loaders; Wheel type loader 100 has body forward structure 101 and body tail 102, and body forward structure 101 can be linked towards the mode that can change with respect to body tail 102 with body forward structure 101 through a pair of hydraulic steering cylinder 103a, 103b (with reference to Fig. 2) with body tail 102 with the relative rotation.Working rig 104 and front-wheel 105 before on body forward structure 101, being provided with are provided with operator's compartment 106 and trailing wheel 107 on body tail 102.In operator's compartment 106, be provided with driver's seat 108, bearing circle 109, function lever apparatus 110 and acceleration pedal, fine motion pedal operating mechanisms such as (not shown).Before working rig 104 constitute by scraper bowl 111 and lift arm 112, scraper bowl 111 through scraper bowl hydraulic actuating cylinder 114 flexible tilt, the dumping action, lift arm 112 is through the flexible action up and down of arm hydraulic cylinder 113.
Fig. 2 is the figure of steering swivel system of the working truck of expression the 1st embodiment of the present invention.
In Fig. 2, the steering swivel system of this embodiment has: primary mover (diesel engine) 1; Have by the Hydraulic Pump 2 of the variable capacity control of this prime mover driven (regulating control) 2a; Above-mentioned a pair of hydraulic steering cylinder 103a, 103b by the hydraulic oil driving that sprays from this Hydraulic Pump 2; Convertible valve 4 is to controlling to the direction and the flow of the hydraulic oil of hydraulic steering cylinder 103a, 103b supply from Hydraulic Pump 2; Fluid-link steering unit 5 links with bearing circle 109, and the rotary manipulation of direction of passage dish 109 moves, and based on the hydraulic oil generation of guide's hydraulic power source (pump) 13 and the rotation amount and the hand of rotation control corresponding pressure of bearing circle 109; Sequence valve 7; Be configured between Hydraulic Pump 2 and the convertible valve 4; Carry out the front and back pressure reduction of the inlet restriction formula oil circuit of convertible valve 4 is remained on the control of expected value (afterwards stating); To preferentially supply to hydraulic steering cylinder 103a, 103b from the hydraulic oil of Hydraulic Pump 2 ejection thus, and will supply to operation with hydraulic circuit 121 from the residual flow of the hydraulic oil of Hydraulic Pump 2 ejections.
Convertible valve 4 has as the valve plunger 4c of valve plug and a pair of compression zone 4a, the 4b that are positioned at the two ends of this valve plunger 4c, when driving pressure is imported into compression zone 4a, 4b, with this driving pressure driving valve plunger 4c correspondingly, makes changes stroke.Convertible valve 4 has the meter characteristic that makes the aperture area increase along with the stroke increase of valve plunger 4c.
Operation is the scraper bowl hydraulic actuating cylinder 114 and the arm hydraulic cylinder 113 supply hydraulic oil of usual practice such as above-mentioned previous crops industry machine 104 with hydraulic circuit 121, and makes the loop of scraper bowl 111 and lift arm 112 actions, has known control cock device.
Fluid-link steering unit 5 has calibrate valve 11 and gerotor pump 12, and the operator is rotated operation to bearing circle 109, and calibrate valve 11 correspondingly rotates with its hand of rotation, and certain operating position A or B about being switched to from graphic center position.
When calibrate valve 11 is switched to the A position, be fed into gerotor pump 12 from the hydraulic oil of guide's hydraulic power source 13 via internal path, the oil circuit 15 of the A position of oil circuit 14, calibrate valve 11, gerotor pump 12 is rotated action through the supply of this hydraulic oil.The hydraulic oil that has passed through gerotor pump 12 is got back to fuel tank via the internal path of the A position of oil circuit 16, calibrate valve 11, oil circuit 17a and through the flow regulating valve 18a that is located on this oil circuit 17a again.On oil circuit 17a, pass through the corresponding pressure of flow (control presssure) of flow regulating valve 18a generation and hydraulic oil this moment.Convertible valve 11 as after state, be switched to the C position in diagram left side from graphic center position based on the pressure (control presssure) that produces by this flow regulating valve 18a.
On the other hand; The spinning movement of gerotor pump 12 feeds back to calibrate valve 11; 12 pairs of flows with the corresponding hydraulic oil of rotary manipulation amount (addendum modification of calibrate valve 11) of bearing circle 109 of gerotor pump measure the professional etiquette of going forward side by side when quantitatively rotating; Calibrate valve 11 is got back to center position, cuts off from the supply of oil circuit 14 to the hydraulic oil of oil circuit 15.Thus, the hydraulic oil of oil circuit 17a becomes tank pressure, and convertible valve 4 is got back to graphic center position.
Be switched at calibrate valve under the situation of B position, carry out and above-mentioned opposite action.That is, supply to gerotor pump 12 from the hydraulic oil of guide's hydraulic power source (pump) 13 via internal path, the oil circuit 16 of the B position of oil circuit 14, calibrate valve 11, gerotor pump 12 is rotated action through the supply of this hydraulic oil.The hydraulic oil that has passed through gerotor pump 12 is got back to fuel tank via the internal path of the B position of oil circuit 15, calibrate valve 11, oil circuit 17b and through the flow regulating valve 18b that is located at this oil circuit 17b again.Through the flow corresponding pressure (control presssure) of flow regulating valve 18b generation with hydraulic oil, be switched to the D position on diagram right side this moment from graphic center position on oil circuit 17b.
12 pairs of flows with the corresponding hydraulic oil of rotary manipulation amount (addendum modification of calibrate valve 11) of bearing circle 109 of gerotor pump measure the professional etiquette of going forward side by side when quantitatively rotating, and calibrate valve 11 is got back to center position, and cut off from the supply of oil circuit 14 to the hydraulic oil of oil circuit 16.Thus, the hydraulic oil of oil circuit 17b becomes tank pressure, and convertible valve 4 is got back to graphic center position.
Sequence valve 7 has ingress port 7a and the 1st and the 2 two outlet port 7b, 7c; Ingress port 7a is connected with Hydraulic Pump 2 through oil circuit 21; The 1st outlet port 7b is connected with convertible valve 4 through oil circuit 22, and the 2nd outlet port 7c is connected with hydraulic circuit 121 with operation through oil circuit 23.In addition; Sequence valve 7 is the guiding valves that can between the switching position F in switching position E that illustrates the right side and diagram left side, move; When the valve plunger of sequence valve 7 is positioned at the position E on diagram right side; Make the access standard-sized sheet between ingress port 7a and the 1st outlet port 7b, and make the access full cut-off between ingress port 7a and the 2nd outlet port 7c, when being positioned at the position F in diagram left side; Make the access full cut-off between ingress port 7a and the 1st outlet port 7b, and make the access standard-sized sheet between ingress port 7a and the 2nd outlet port 7c.In addition; Position E from the diagram right side moves (promptly to the position F in diagram left side along with the valve plunger of sequence valve 7; Along with right-hand to moving) to diagram; The aperture area of the access between ingress port 7a and the 1st outlet port 7b tightens (diminishing) gradually; The aperture area of the access between ingress port 7a and the 2nd outlet port 7c is opened (becoming big) gradually, along with the valve plunger of sequence valve 7 moves (that is, along with to the diagram left to moving) from the position F in diagram left side to the position E on diagram right side; The aperture area of the access between ingress port 7a and the 2nd outlet port 7c tightens (diminishing) gradually, and the aperture area of the access between ingress port 7a and the 1st outlet port 7b is opened (becoming big) gradually.
In addition; The compression zone 24b that sequence valve 7 has compression zone 24a that the valve plunger of sequence valve 7 is suppressed to the position E on diagram right side and spring 25 and the valve plunger of sequence valve 7 is suppressed to the position F in diagram left side; The pressure of the outlet side of convertible valve 4 (the actuating oil circuit 26a between convertible valve 4 and hydraulic steering cylinder 103a, the 103b, the pressure of 26b; Or the load pressure of hydraulic steering cylinder 103a, 103b) import compression zone 24a via guide's oil circuit 27, the pressure of the entrance side of convertible valve 4 (pressure of the oil circuit 22 between sequence valve 7 and the convertible valve 4) imports compression zone 24b via guide's oil circuit 28.
Because compression zone 24a, 24b suppress the valve plunger of sequence valve 7 each other round about; So being imported into the situation that the pressure of the entrance side of compression zone 24a and convertible valve 4 is imported into compression zone 24b, the pressure of the outlet side of convertible valve 4 means; For to the valve plunger of sequence valve 7 to the right-hand front and back pressure reduction that acts on the inlet restriction formula oil circuit of convertible valve 4 to suppressing of diagram (below, suitably be called for short and make " the front and back pressure reduction of convertible valve 4 ").
Spring 25 is configured for setting the set mechanism of the front and back pressure differential expected value of convertible valve 4; If acting on the front and back pressure reduction of the last convertible valve 4 of compression zone 24a, the 24b of sequence valve 7 becomes than big by spring 25 target value set; Then make the valve plunger of sequence valve 7 right-hand to moving to diagram; The aperture area that makes ingress port 7a and the 1st export the access between the port 7b tightens gradually and reduces the supply flow rate to convertible valve 4, thereby the front and back pressure reduction of convertible valve 4 is reduced.At this moment, the residual flow from Hydraulic Pump 2 is fed into operation with hydraulic circuit 121.If acting on the front and back pressure reduction of the last convertible valve 4 of compression zone 24a, the 24b of sequence valve 7 becomes than little by spring 25 target value set; The valve plunger that then makes sequence valve 7 on the contrary is to illustrating left to moving; And the aperture area that makes the access between ingress port 7a and the 1st outlet port 7b opens gradually and increases the supply flow rate to convertible valve 4, thereby the front and back pressure reduction of convertible valve 4 is increased.Thus, sequence valve 7 is controlled, so that the front and back pressure reduction of the inlet restriction formula oil circuit of convertible valve 4 is remained on by spring 25 (set mechanism) target value set.
And the steering swivel system of this embodiment also has: detect the pressure sensor 6a that oil circuit 17a goes up the pressure (control presssure) that is produced by flow regulating valve 18a; Detect the pressure sensor 6b that oil circuit 17b goes up the pressure (control presssure) that is produced by flow regulating valve 18b; Preceding operation detection device 31; Controller 32; Electromagnetic valve 33a, 33b.The detection signal of pressure sensor 6a, 6b and before the detection signal of operation detection device 31 be transfused to controller 32, the computing that controller 32 is stipulated according to this input value, and to the control current of electromagnetic valve 33,33b output regulation.Electromagnetic valve 33a, 33b move according to this control current, and output and control current corresponding driving pressure.This driving pressure is imported into compression zone 4a, the 4b of convertible valve 4.
Fig. 3 is the figure of an example of operation detection device before the expression.As previously mentioned, in the operator's compartment 106 of wheel type loader, be provided with function lever apparatus 110.This function lever apparatus 110 have can omnipotent operation control lever 110c; When this control lever 110c is operated on a direction (for example fore-and-aft direction) of cross; Function lever apparatus 110a as scraper bowl 111 usefulness of preceding working rig 104 plays a role; Control lever 110c when the other direction (for example left and right directions) of cross is gone up operation, is played a role as the function lever apparatus 110b of lift arm 112 usefulness of preceding working rig 104.In addition, function lever apparatus 110a, 110b are the hydraulic pilot formula, generate the operational ton on each direction of operating with control lever 110c respectively and press with the corresponding operated pilot of the direction of operating that with the center position is the boundary.This operated pilot press via guide's oil circuit 43a or 43b and guide's oil circuit 44a or 44b import to not shown scraper bowl with control cock and lift arm with in the control cock; Through these control cock are carried out blocked operation, come drive controlling scraper bowl hydraulic actuating cylinder 114 and arm hydraulic cylinder 113.Scraper bowl constitutes the part of the control cock device that is had with hydraulic circuit 121 as operation with control cock with control cock and lift arm.
43a, the last reciprocable valve 45 that is connected with of 43b on the guide oil road; 44a, the last reciprocable valve 46 that is connected with of 44b on the guide oil road; Outgoing side in these reciprocable valve 45,46 also is connected with reciprocable valve 47, and the top pressure that the operated pilot that in guide oil road 43a, 43b and guide's oil circuit 44a, 44b, generates is pressed takes out through reciprocable valve 47.Outgoing side in this reciprocable valve 47 is connected with pressure sensor 48, and the pressure that is taken out by reciprocable valve 47 is detected by pressure sensor 48.The detection signal of pressure sensor 48 is input to controller 32 as preceding operation signal.Operation detection device 31 before reciprocable valve 45～47 and pressure sensor 48 constitute.
Fig. 4 is the functional block diagram of the contents processing of expression controller 32.Controller 32 has the 1st basic driver calculation of pressure 32a of portion, the 2nd basic driver calculation of pressure 32b of portion, coefficient of correction calculating part 32c, the 1st target drives calculation of pressure 32d of portion, the 2nd target drives calculation of pressure 32e of portion, the 1st control current calculating part 32f, the 2nd control current calculating part 32g.
The 1st basic driver calculation of pressure 32a of portion is the member that the base value to the delivery pressure (the 1st driving pressure) of the electromagnetic valve 33a of the stroke on the diagram right side compression zone 4a that is imported into convertible valve 4, that be used to control convertible valve 4 calculates; Detection signal from pressure sensor 6a input pressure; Make itself and the table contrast that is stored in the memory device then, calculate cooresponding the 1st basic driver pressure of pressure with this moment.In the table of memory device, be set with the relation of input pressure and the 1st basic driver pressure, promptly make the 1st basic driver pressure become big along with input pressure increases.
The 2nd basic driver calculation of pressure 32b of portion is the member that the base value to the delivery pressure (the 2nd driving pressure) of the electromagnetic valve 33b of the stroke in the diagram compression zone 4b that is imported into convertible valve 4, that be used to control convertible valve 4 left side calculates; Detection signal from pressure sensor 6b input pressure; And make itself and the table contrast that is stored in the memory device, calculate cooresponding the 2nd basic driver pressure of pressure with this moment.In the table of memory device, be set with the relation of input pressure and the 2nd basic driver pressure, promptly make the 2nd basic driver pressure become big along with input pressure increases.
Coefficient of correction calculating part 32c be with have or not before working rig 104 operation (below; Be called preceding operation) member that correspondingly coefficient of correction of driving pressure calculated; Operation signal before operation detection device 31 is imported in the past (operated pilot by pressure sensor 48 detects is pressed); Make itself and the table contrast that is stored in the memory device, calculate the cooresponding coefficient of correction of preceding operation signal with this moment.In the table of memory device, be set with the relation of preceding operation signal (operated pilot pressure) and coefficient of correction; For example; With being regarded as the preceding operation signal of situation that the operator operated the control lever 110c of function lever apparatus 110 is that the value P0 that presses of operated pilot is as threshold value; By pressure sensor 48 detected these threshold values of operated pilot pressure ratio P0 hour; Coefficient of correction is less the 1st value (for example 0.5), if operated pilot presses to this threshold value P0 when above, coefficient of correction becomes 2nd value bigger than the 1st value (for example 1.0).
The 1st target drives calculation of pressure 32d of portion is a multiplier, and the 1st basic driver pressure that is calculated by the 1st basic driver calculation of pressure 32a of portion and the coefficient of correction that is calculated by coefficient of correction calculating part 32c are multiplied each other, and calculates the 1st target drives pressure.
The 2nd target drives calculation of pressure 32e of portion is a multiplier, and the 2nd basic driver pressure that is calculated by the 2nd basic driver calculation of pressure 32b of portion and the coefficient of correction that is calculated by coefficient of correction calculating part 32c are multiplied each other, and calculates the 2nd target drives pressure.
The 1st control current calculating part 32f makes the 1st target drives pressure that is calculated by the 1st target drives calculation of pressure 32d of portion and the table contrast that is stored in the memory device, and to calculating with the control current of the cooresponding electromagnetic valve 33a of the 1st target drives pressure.In the table of memory device, be set with the relation of the 1st target drives pressure and control current, promptly control current increased along with the 1st target drives pressure increases.This control current is through not shown amplifier amplification, and quilt is outputed to electromagnetic valve 33a.
The 2nd control current calculating part 32g makes the 2nd target drives pressure that is calculated by the 2nd target drives calculation of pressure 32e of portion and the table contrast that is stored in the memory device, and to calculating with the control current of the cooresponding electromagnetic valve 33b of the 2nd target drives pressure.In the table of memory device, be set with the relation of the 2nd target drives pressure and control current, promptly control current increased along with the 2nd target drives pressure increases.This control current is through not shown amplifier amplification, and quilt is outputed to electromagnetic valve 33b.
More than; Fluid-link steering unit 5, pressure sensor 6a, 6b (the 1st and the 2nd pressure sensor), controller 32, electromagnetic valve 33a, 33b constitute; The serviceability of the preceding working rig 101 that detects based on the rotary manipulation of bearing circle 109 with by preceding operation detection device 31 (preceding operation machine operation testing agency) is to the switching direction of convertible valve 4 and the steering operation control mechanism of controlling through flow.
In addition; Controller 32 with electromagnetic valve 33a, 33b is; Based on by pressure sensor 6a, detected each control presssure of 6b (the 1st and the 2nd pressure sensor) (the 1st and the 2nd control presssure) and by preceding operation detection device 31 (preceding operation machine operation testing agency) detected before the serviceability of working rig 101; The control mechanism that the stroke of convertible valve 4 is controlled, and be along with by pressure sensor 6a, the 6b increase of detected each control presssure respectively, make the stroke of convertible valve 4 become big; And; Before detecting during the operation of working rig 101 through preceding operation detection device 31, with do not detect before compare the control mechanism that the stroke of convertible valve 4 is controlled biglyyer during the operation of working rig 101.
Below, the action like this embodiment of above-mentioned formation is described.
At first; Go simultaneously and operate before the operation of working rig 101; Before operation during working rig 101; Owing to become in the coefficient of correction calculating part 32c of controller 32 more than the preset threshold P0, so in coefficient of correction calculating part 32c, calculate the 2nd bigger value (for example 1.0) as coefficient of correction from the preceding operation signal of preceding operation detection device 31 (operated pilot by pressure sensor 48 detects is pressed).
In addition; Go at the same time and operate before in the operation of working rig 101; For example make under the situation that calibrate valve 11 switched to the A position at operator's rotary manipulation bearing circle 109; In oil circuit 17a, produce pressure, this pressure is detected by pressure sensor 6a, and controller 32 calculates in the 1st basic driver calculation of pressure 32a of portion and cooresponding the 1st basic driver pressure of this pressure.In the 1st target drives calculation of pressure 32d of portion, the 1st basic driver pressure and above-mentioned the 2nd bigger value are multiplied each other, calculate the 1st target drives pressure.And, in the 1st control current calculating part 32f, calculate and the 1st target drives pressure corresponding control current, and export cooresponding control current to electromagnetic valve 33a.Electromagnetic valve 33a moves through this control current, thereby generates and the 1st target drives pressure corresponding driving pressure, and this driving pressure is imported into the compression zone 4a of convertible valve 4.Its result, convertible valve 4 correspondingly drives and makes changes stroke with valve plunger 4c to the C position with this driving pressure, sets and the corresponding aperture area of this stroke.Under this situation, the aperture area of convertible valve 4 becomes and the cooresponding bigger aperture area of the 2nd value of coefficient of correction.Thus; The flow that passes through of convertible valve 4 increases; Rotary manipulation with respect to bearing circle 109; The actuating speed of hydraulic steering cylinder 103a, 103b (turning velocity of wheel) accelerates, can reduce go simultaneously and operate before the fatigue of operator when steering operation in the operation of working rig 101, improve operating efficiency.
And in going separately; Because the preceding operation signal (operated pilot by pressure sensor 48 detects is pressed) from preceding operation detection device 31 is littler than the threshold value P0 that is set among the coefficient of correction calculating part 32c; So in coefficient of correction calculating part 32c, calculate the 1st less value (for example 0.5) as coefficient of correction.
In addition; In this goes separately; Under the situation about for example switching to the A position at operator's rotary manipulation bearing circle 109 and with calibrate valve 11, in oil circuit 17a, produce pressure, this pressure is detected by pressure sensor 6a; Controller 32 calculates and cooresponding the 1st basic driver pressure of this pressure in the 1st basic driver calculation of pressure 32a of portion.In the 1st target drives calculation of pressure 32d of portion, the 1st basic driver pressure and above-mentioned the 1st less value are multiplied each other, calculate the 1st target drives pressure.And, in the 1st control current calculating part 32f, calculate and the 1st target drives pressure corresponding control current, and export cooresponding control current to electromagnetic valve 33a.Electromagnetic valve 33a moves through this control current, and generates and the 1st target drives pressure corresponding driving pressure, and this driving pressure is imported into the compression zone 4a of convertible valve 4.Its result is exactly, and convertible valve 4 and this driving pressure correspondingly drive valve plunger 4c and stroke is changed to the C position, set and the corresponding aperture area of this stroke, promptly set the corresponding less aperture area of the 1st value with coefficient of correction.Thus, the flow that passes through of convertible valve 4 reduces, and with respect to the rotary manipulation of bearing circle 109, the actuating speed of hydraulic steering cylinder 103a, 103b (turning velocity of wheel) is slack-off, has improved the safety when going steering operation separately.
Under the situation about switching to the B position at operator's rotary manipulation bearing circle 109 and with calibrate valve 11 too.
In this such embodiment; Go at the same time respectively and operate before operation and each stage of going separately of working rig 101; Make wheel steering speed become best value, can guarantee operating efficiency and safety with respect to the rotary manipulation of bearing circle 109.
In addition, before operation, during working rig 101,,, can access good operability so do not need operator's operation owing to carry out the change of wheel steering speed automatically.
And; Owing to detect the control presssure that produces by fluid-link steering unit 5; And become the stroke of the earth control convertible valve 4 along with the increase of the control presssure of this detection; So compare with the mode of direct drive convertible valve 4, fluid-link steering unit 5 can also can access good operability in this through the rotary manipulation of less power travel direction dish 4.
With reference to Fig. 5 the 2nd embodiment of the present invention is described.In the 1st embodiment; In the employed table of calculating of the coefficient of correction calculating part 32c of Fig. 4; The threshold setting of preceding operation signal (operated pilot pressure) is become to be regarded as the operator has carried out the operated pilot pressure of operation to the control lever 110c of function lever apparatus 110 value P0; But, in this embodiment, this threshold setting is become different values.
Promptly; In this embodiment; Relation for preceding operation signal in the table of the coefficient of correction calculating part 32Ac that is stored in Fig. 5 (operated pilot pressure) and coefficient of correction; Before the preceding operation signal (operated pilot pressure) of transverse axis is divided into the action of working rig smaller, as the operated pilot of the prudent microoperation operation of needs press the action of scope and preceding working rig bigger, as the operated pilot pressure scope of common operation task, the value Pa of the operated pilot pressure of its boundary is set as threshold value.
Go at the same time and operate before during the operation of working rig 101; In the scraper bowl 111 of preceding working rig 101, exist under the state or the state above scraper bowl 111 is positioned at of Loaded goods; Need prudent operation, in this case, when rotary manipulation bearing circle 109; If turning velocity accelerates, might take place then that loading and unloading thing in the scraper bowl is scattered, the vehicle body action is disorderly.
In this embodiment; Go at the same time and operate before in the operation of working rig, carrying out before the action of working rig smaller, when needing the operation of prudent microoperation, it is below the threshold value Pa that operated pilot is pressed; Because coefficient of correction becomes the 1st less value (for example 0.5); So the stroke of convertible valve 4 can Be Controlled must diminish, can be really and carry out the microoperation operation exactly, can prevent Loaded goods in the past working rig 101 be scattered or the vehicle body action disorderly.And during the common operation that the action of working rig 101 is bigger before carrying out; Operated pilot press to surpass threshold value Pa, because coefficient of correction becomes the 2nd bigger value (for example 1.0), so the stroke Be Controlled of convertible valve 4 must become big; Go at the same time and operate before during the operation of working rig; Can easily switch and turn to minimizing operator's fatigue, raising operating efficiency.
According to this such embodiment, can access the effect identical with the 1st embodiment, and, go at the same time and operate before during the operation of working rig, can be really and carry out the microoperation operation exactly.
With reference to Fig. 6 and Fig. 7 the 3rd embodiment of the present invention is described.
Fig. 6 is the figure of steering swivel system of the working truck of this embodiment of expression.
In Fig. 6; In the steering swivel system of this embodiment; Replace pressure sensor 6a shown in Figure 1,6b and electromagnetic valve 33a, 33b; The control presssure that use produces fluid-link steering unit 5 imports compression zone 4a, guide's oil circuit 131a of 4b, the 131b of convertible valve 4, through the control presssure that is produced by fluid-link steering unit 5 convertible valve 4 is directly switched.
In addition, in the steering swivel system of this embodiment, replace sequence valve 7 shown in Figure 1, use can be altered to the front and back pressure reduction of the inlet restriction formula oil circuit of convertible valve 4 the sequence valve 7A of expected value.
Promptly; Sequence valve 7 in sequence valve 7A and the 1st embodiment is same; The compression zone 24b that has compression zone 24a that the valve plunger of sequence valve 7A is suppressed to the position E on diagram right side and spring 25, the valve plunger of sequence valve 7A is suppressed to the position F in diagram left side; And have the 2nd compression zone 24c that the valve plunger of sequence valve 7A is suppressed to the position F in diagram left side, control presssure is imported into this compression chamber 24c via guide's oil circuit 29.
Spring 25 is configured for setting the set mechanism of the front and back pressure differential expected value of convertible valve 4, and compression zone 24c constitutes the expected value correction mechanism that the front and back pressure differential expected value of being set by spring 25 is revised.The front and back pressure reduction that acts on the last convertible valve 4 of compression zone 24a, the 24b of sequence valve 7A is set through spring 25; If it is bigger than the expected value of being revised by compression zone 24c; Then make the valve plunger of sequence valve 7A right-hand to moving to diagram; The aperture area that makes ingress port 7a and the 1st export the access between the port 7b tightens gradually and reduces the supply flow rate to convertible valve 4, and the front and back pressure reduction of convertible valve 4 is diminished.At this moment, the residual flow from Hydraulic Pump 2 is fed into operation with hydraulic circuit 121.If the front and back pressure reduction that acts on the last convertible valve 4 of compression zone 24a, the 24b of sequence valve 7A is than little by spring 25 and compression zone 24c target value set; Then on the contrary; The valve plunger that makes sequence valve 7A is to illustrating left to moving; And the aperture area of the access between ingress port 7a and the 1st outlet port 7b is opened gradually, thus increase supply flow rate to convertible valve 4, the front and back pressure reduction of convertible valve 4 is increased.Thus, sequence valve 7A controls as follows, promptly sets the front and back pressure reduction of the inlet restriction formula oil circuit of convertible valve 4 through spring 25, and this front and back pressure reduction is remained on the expected value of being revised by compression zone 24c.
Here, spring 25 is set the base value (steady state value) of above-mentioned expected value, and compression zone 24c adjusts this base value through control presssure, sets expected value for variable value.The control presssure that imports among the compression zone 24c is configured to the little value of conversion pressure value than the elastic force pressure of spring 25 so that the elastic force pressure sum of spring 25 and compression zone 24c acts on the mode that the diagram left makes progress.We can say that also spring 25 and compression zone 24c are configured for setting the set mechanism of the front and back pressure differential expected value of convertible valve 4.
And; The steering swivel system of this embodiment also has the preceding operation detection device 31 identical with the 1st embodiment; And have controller 132 and electromagnetic valve 133; The detection signal of preceding operation detection device 31 is imported into controller 132, and the computing that controller 132 is stipulated is to electromagnetic valve 133 output control current.Electromagnetic valve 133 moves through this control current, output and this control current control corresponding pressure.This control presssure is imported into the compression zone 24c of sequence valve 7A via guide's oil circuit 29.
Fig. 7 is the functional block diagram of the contents processing of expression controller 132.Controller 132 has sequence valve setting pressure calculating part 132a, electromagnetic valve delivery pressure calculating part 132b, control current calculating part 132c.
Sequence valve setting pressure calculating part 132a is the member to calculating with preceding operation corresponding order valve setting pressure; Operation signal before operation detection device 31 is imported in the past (operated pilot through pressure sensor shown in Figure 3 48 detects is pressed); And make itself and the table contrast that is stored in the memory device, calculate the cooresponding setting pressure of preceding operation signal with this moment.In the table of memory device, be set with the relation of preceding operation signal (operated pilot pressure) and setting pressure; For example; With being regarded as value P0 that the operated pilot of preceding operation signal of situation that the operator operated the control lever 110c of function lever apparatus 110 presses as threshold value; By pressure sensor 48 detected these threshold values of operated pilot pressure ratio P0 hour; Setting pressure is the 1st less value Pseta, if operated pilot presses to more than this threshold value P0, then setting pressure becomes the 2nd value Psetb bigger than the 1st value Pseta.Here, the sequence valve setting pressure that is calculated by calculating part 132a means the front and back pressure differential expected value of the convertible valve 4 that sets through the set mechanism that is made up of the spring 25 of sequence valve 7A and compression zone 24c as previously mentioned.The 1st value Pseta is for example 20Kg/cm 2, the 2nd value Psetb is for example 30Kg/cm 2
Electromagnetic valve delivery pressure calculating part 32b is the member of the delivery pressure (control presssure) that is used to calculate electromagnetic valve 33, and this delivery pressure is used to obtain the setting pressure that calculated by sequence valve setting pressure calculating part 32a.Make this setting pressure and the table contrast that is stored in the memory device, calculate delivery pressure with the cooresponding electromagnetic valve 33 of this setting pressure.In the table of memory device, be set with the relation of setting pressure and delivery pressure, promptly delivery pressure diminished along with setting pressure increases.Here, for example if the conversion pressure value (base value) of the elastic force pressure of the diagram left of spring 25 is 30Kg/cm 2, be that the 1st value Pseta is 20Kg/cm then at the sequence valve setting pressure that calculates by calculating part 32a 2, in this case, in electromagnetic valve delivery pressure calculating part 32b, calculate 10Kg/cm 2Control presssure, be that the 2nd value Psetb is 30Kg/cm at the sequence valve setting pressure that calculates by calculating part 32a 2Situation under, calculate 0Kg/cm at electromagnetic valve delivery pressure calculating part 32b 2Control presssure.
Control current calculating part 32c is the member of the control current (drive current) that is used to calculate electromagnetic valve 35, and this control current is used to obtain the delivery pressure of the electromagnetic valve 33 obtained by electromagnetic valve delivery pressure calculating part 32b.Make the delivery pressure and the table contrast that is stored in the memory device of the electromagnetic valve of obtaining by electromagnetic valve delivery pressure calculating part 32 33, calculate control current with the cooresponding electromagnetic valve 33 of this delivery pressure.In the table of memory device, be set with the relation of delivery pressure and control current, promptly control current increased along with delivery pressure increases.This control current is through not shown amplifier amplification, and quilt is outputed to electromagnetic valve 33.
More than; The compression zone 24c of fluid-link steering unit 5, guide's oil circuit 131a, 131b, controller 132, electromagnetic valve 133, guide's oil circuit 29, sequence valve 7A constitutes; Based on the rotary manipulation of bearing circle 109 and by preceding operation detection device 31 (preceding operation machine operation testing agency) detected before the serviceability of working rig 101, to the switching direction of convertible valve 4 and the steering operation control mechanism of controlling through flow.
In addition; The compression zone 24c of controller 132, electromagnetic valve 33, guide's oil circuit 29, sequence valve 7A constitutes, and is the control mechanism that the front and back pressure differential expected value of the convertible valve 4 set of spring 25 changes according to the serviceability of the preceding working rig 101 that is detected by preceding operation detection device 31 (preceding operation machine operation testing agency) to the set mechanism by sequence valve 7A.
As this embodiment of above-mentioned formation in; Before operation during working rig 101; In the sequence valve setting pressure calculating part 132a of controller 132; Calculate bigger value promptly the 2nd value Psetb be imported into the compression zone 24c of sequence valve 7A as setting pressure with this value control corresponding pressure, in sequence valve 7A, set and should be worth as the front and back pressure differential expected value of convertible valve 4.Sequence valve 7A makes the front and back pressure reduction of convertible valve 4 remain on the control of its expected value.Thus; The flow that passes through of convertible valve 4 increases; Accelerate with respect to the hydraulic steering cylinder 103a of the rotary manipulation of bearing circle 109, the actuating speed (turning velocity of wheel) of 103b; Can reduce go at the same time and operate before fatigue during operator's steering operation in the operation of working rig 101, improve operating efficiency.
And in going separately; In the sequence valve setting pressure calculating part 132a of controller 132; Calculating less value is that the 1st value Pseta is as setting pressure; Be imported into the compression zone 24c of sequence valve 7A with this value control corresponding pressure, in sequence valve 7A, setting as the front and back pressure differential expected value of convertible valve 4 should value.Sequence valve 7A makes the front and back pressure reduction of convertible valve 4 remain on the control of this expected value.Thus, the flow that passes through of convertible valve 4 reduces, owing to do not accelerate with respect to the hydraulic steering cylinder 103a of the rotary manipulation of bearing circle 109, the actuating speed (turning velocity of wheel) of 103b, so the safety when having improved the steering operation when going separately.
In addition; Same with the 1st embodiment, can obtain good operability with the rotary manipulation of less power travel direction dish 109; And; In case the electric system et out of order of controller 132, electromagnetic valve 33 etc. also can positively carry out the handling maneuver of wheel type loader, can guarantee higher safety.
With reference to Fig. 8 the 4th embodiment of the present invention is described.
In above-mentioned the 3rd embodiment; In the employed table of calculating of the sequence valve setting pressure calculating part 132a of Fig. 7; The threshold setting of preceding operation signal (operated pilot pressure) is become to be regarded as the operator control lever 110c of function lever apparatus 110 has been carried out the value P0 that the operated pilot of operation is pressed, still, in this embodiment; With with respect to the identical ground of the distortion in the 2nd embodiment of the 1st embodiment, its threshold setting is become different values.
Promptly; In this embodiment; In the relation of preceding operation signal (operated pilot pressure) in the table of the sequence valve setting pressure calculating part 132a that is stored in Fig. 8 and the setting pressure of sequence valve 7a; Before the preceding operation signal (operated pilot pressure) of transverse axis is divided into the operated pilot of the action microoperation operation smaller, that needs are prudent of working rig press the action of scope and preceding working rig bigger, the operated pilot of operation task is pressed scope usually, set as threshold value with the value Pa of the operated pilot pressure of its boundary.
Thus; Go at the same time and operate before in the operation of working rig; Before carrying out the action of working rig smaller, when needing prudent microoperation operation, operated pilot is pressed to below the threshold value Pa, because the setting pressure of sequence valve 7A becomes the 1st less value Pseta (20Kg/cm for example 2), so the front and back pressure reduction Be Controlled of convertible valve 4 must diminish, can be really and carry out the microoperation operation exactly, can prevent Loaded goods in the past working rig 101 drop and the vehicle body action disorderly.And during the common operation that the action of working rig 101 is bigger before carrying out, operated pilot is pressed and is surpassed threshold value Pa, because the setting pressure of sequence valve 7A becomes the 2nd bigger value Psetb (30Kg/cm for example 2), so the front and back pressure reduction Be Controlled of convertible valve 4 must become greatly, go at the same time and operate before can easily switch in the operation of working rig and turn to, reduced operator's fatigue, improved operating efficiency.

Claims (10)

1. the hydrostatic steering system of a working truck has:
Hydraulic Pump (2);
Hydraulic steering cylinder (103a, 103b) by the hydraulic oil driving that sprays from this Hydraulic Pump;
To the direction of the hydraulic oil supplied with to said hydraulic steering cylinder from said Hydraulic Pump and the convertible valve (4) that flow is controlled;
By the bearing circle (109) of operator's rotary manipulation,
Rotary manipulation according to said bearing circle switches said convertible valve, and the said hydraulic steering cylinder of drive controlling, it is characterized in that this hydrostatic steering system also has:
Be used to detect the preceding operation machine operation testing agency (31) of serviceability of the preceding working rig (104) of the body forward structure (101) that is arranged on said working truck;
Based on the rotary manipulation of said bearing circle (109) and by operation machine operation testing agency (31) before said detect said before the serviceability of working rig (104), to the switching direction of said convertible valve (4) and the steering operation control mechanism of controlling through flow (5,6a, 6b, 32,33a, 33b; 5,131a, 131b, 132,133,29,24c).
2. the hydrostatic steering system of working truck as claimed in claim 1 is characterized in that:
Said steering operation control mechanism has:
Fluid-link steering unit (5) links with said bearing circle (109), and the rotary manipulation through this bearing circle moves, and produces rotation amount and hand of rotation the corresponding the 1st and the 2nd control presssure with said bearing circle based on the hydraulic oil of guide's hydraulic power source (13);
The the 1st and the 2nd pressure sensor (6a, 6b) detects the 1st and the 2nd control presssure that is produced by said fluid-link steering unit respectively;
First control mechanism (32,33a, 33b); Based on the 1st and the 2nd control presssure that detects by the said the 1st and the 2nd pressure sensor and by operation machine operation testing agency (31) before said detect said before the serviceability of working rig (104), the stroke of said convertible valve (4) is controlled.
3. the hydrostatic steering system of working truck as claimed in claim 2 is characterized in that:
Said first control mechanism (32,33a, 33b) is controlled as follows; Along with increasing by the said the 1st and the 2nd pressure sensor (6a, 6b) difference the detected the 1st and the 2nd control presssure; Make the stroke of said convertible valve (4) become big; And, when detect through operation machine operation testing agency (31) before said said before during the operation of working rig (104), big when making the operation of stroke said preceding working rig of said convertible valve than not detecting.
4. the hydrostatic steering system of working truck as claimed in claim 2 is characterized in that:
Said first control mechanism (32,33a, 33b) is controlled as follows; Along with the 1st and the 2nd control presssure that is detected respectively by the said the 1st and the 2nd pressure sensor (6a, 6b) increases; Make the stroke of said convertible valve (4) become big; And, when detect through operation machine operation testing agency (31) before said said before during the bigger operation of the action of working rig (104), big when making the bigger operation of the action of stroke said preceding working rig of said convertible valve than not detecting.
5. like the hydrostatic steering system of each described working truck of claim 2～4, it is characterized in that:
Said convertible valve (4) has: as the valve plunger of valve plug; The the 1st and the 2nd compression zone (4a, 4b), the said the 1st and the 2nd compression zone (4a, 4b) is positioned at the two ends of this valve plunger, and is imported into driving pressure respectively, and drive said valve plunger and make said changes stroke according to this driving pressure,
Said first control mechanism has:
The the 1st and the 2nd electromagnetic valve (33a, 33b) with the corresponding setting respectively of the said the 1st and the 2nd compression zone, moves through control current, and output and this control current corresponding driving pressure;
Controller (32) is imported the detected value of the said the 1st and the 2nd pressure sensor (6a, 6b) and preceding operation machine operation testing agency (31), and based on the calculating that these detected values are stipulated, is exported said control current to the said the 1st and the 2nd electromagnetic valve.
6. the hydrostatic steering system of working truck as claimed in claim 5 is characterized in that:
Said controller (32) has:
The 1st computing mechanism (32a) is used to calculate the 1st target drives pressure, and said the 1st target drives pressure is along with the increase through the detected control presssure of said the 1st pressure sensor (6a) increases;
The 2nd computing mechanism (32b) is used to calculate the 2nd target drives pressure, and said the 2nd target drives pressure is along with the increase of the control presssure that detects through said the 2nd pressure sensor (6b) increases;
The 3rd computing mechanism (32c, 32d, 32e); When detecting the operation of said preceding working rig (104) through operation machine operation testing agency (31) before said; To the said the 1st and the 2nd target drives pressure revise so that its become than detect said before big value during the operation of working rig
Export said control current to the said the 1st and the 2nd electromagnetic valve (33a, 33b), to obtain the 1st and the 2nd target drives pressure by said the 3rd computing mechanism correction.
7. the hydrostatic steering system of working truck as claimed in claim 1 is characterized in that:
Also has sequence valve (7A); It has the set mechanism (25) that is configured between said Hydraulic Pump (2) and the said convertible valve (4), is used to set the front and back pressure differential expected value of said convertible valve; Make the front and back pressure reduction of said convertible valve remain on said expected value through control; Can the hydraulic oil from the ejection of said Hydraulic Pump preferentially be supplied to said hydraulic steering cylinder (103a, 103b), and with residual flow supply to drive working rig operation with hydraulic circuit (121)
Said steering operation control mechanism has:
Fluid-link steering unit (5), itself and said bearing circle (109) link, and move through the rotary manipulation of this bearing circle, based on the hydraulic oil generation of guide's hydraulic power source (13) and the rotation amount and the hand of rotation control corresponding pressure of said bearing circle;
Guide's oil circuit (131a, 131b), it will import the compression zone (4a, 4b) of said convertible valve by the control presssure that said fluid-link steering unit produces and said convertible valve will be switched;
Second control mechanism (132,133,29,24c); Its according to by operation machine operation testing agency (31) before said detected said before the serviceability of working rig (104), the front and back pressure differential expected value of the said convertible valve set by the set mechanism (25) of said sequence valve is changed.
8. the hydrostatic steering system of working truck as claimed in claim 7 is characterized in that:
When detecting the operation of said preceding working rig (104) by operation machine operation testing agency (31) before said; Said second control mechanism (132,133,29,24c) changes said expected value, so that bigger during the operation of working rig before said than not detecting by set mechanism (25) target value set of said sequence valve.
9. the hydrostatic steering system of working truck as claimed in claim 7 is characterized in that:
Detect by operation machine operation testing agency (31) before said said before during the bigger operation of the action of working rig (104); Said second control mechanism (132,133,29,24c) changes said expected value, so that bigger during the bigger operation of the action of working rig before said than not detecting by set mechanism (25) target value set of said sequence valve.
10. the hydrostatic steering system of working truck as claimed in claim 7 is characterized in that:
Said second control mechanism has:
Electromagnetic valve (133), said electromagnetic valve moves through control current, and output and this control current control corresponding pressure;
Expected value change control presssure compression zone, said expected value change control presssure compression zone is located on the said sequence valve (7A), according to the said control presssure of said electromagnetic valve (133) output to changing by said set mechanism (25) target value set;
Controller (132); The detected value of operation machine operation testing agency (31) before said controller input is said; And based on this detected value calculate with said before the serviceability of working rig (104) be worth accordingly; Export said control current to said electromagnetic valve (133), so that the said expected value of being set by said set mechanism (25) changes to and should be worth accordingly with serviceability of said preceding working rig (104).
CN2007800345490A 2006-12-26 2007-12-26 Steering system for working vehicle Expired - Fee Related CN101516715B (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP350432/2006 2006-12-26
JP2006350432A JP4993575B2 (en) 2006-12-26 2006-12-26 Steering system for work vehicle
JP350453/2006 2006-12-26
JP2006350453A JP4941928B2 (en) 2006-12-26 2006-12-26 Steering system for work vehicle
PCT/JP2007/075033 WO2008081843A1 (en) 2006-12-26 2007-12-26 Steering system for working vehicle

Publications (2)

Publication Number Publication Date
CN101516715A CN101516715A (en) 2009-08-26
CN101516715B true CN101516715B (en) 2012-01-25

Family

ID=39657288

Family Applications (1)

Application Number Title Priority Date Filing Date
CN2007800345490A Expired - Fee Related CN101516715B (en) 2006-12-26 2007-12-26 Steering system for working vehicle

Country Status (2)

Country Link
JP (1) JP4941928B2 (en)
CN (1) CN101516715B (en)

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5631882B2 (en) * 2008-09-30 2014-11-26 ボルボ コンストラクション イクイップメント アーベー Hydraulic steering system including first and second steering members, and vehicle including hydraulic steering system
KR101652111B1 (en) * 2009-12-17 2016-08-29 두산인프라코어 주식회사 Hydraulic system for construction machinery
CN101954927B (en) * 2010-10-19 2012-01-11 中国人民解放军总装备部军械技术研究所 Multi-load hydraulic sensing system for single-power source and multi-system working
WO2013044488A1 (en) * 2011-09-29 2013-04-04 长沙中联重工科技发展股份有限公司 Control method of steering central shaft and hydraulic control system
JP6001846B2 (en) * 2011-12-08 2016-10-05 川崎重工業株式会社 Hydraulic control device and construction machine including the same
JP5362113B1 (en) * 2012-03-29 2013-12-11 株式会社小松製作所 Steering device for wheel loader
CN103465955A (en) * 2013-09-24 2013-12-25 徐州重型机械有限公司 Hydraulic control valve bank for locking steering shaft of crane, steering system and crane
JP6134263B2 (en) * 2013-12-27 2017-05-24 株式会社Kcm Hydraulic drive system
CN104029722B (en) * 2014-01-23 2016-09-07 广西柳工机械股份有限公司 Engineering machinery hydraulic steering
JP6554444B2 (en) * 2016-06-09 2019-07-31 日立建機株式会社 Work machine
JP6856548B2 (en) * 2017-01-10 2021-04-07 株式会社小松製作所 Work vehicle and control method
JP6858723B2 (en) * 2018-03-28 2021-04-14 日立建機株式会社 Wheel loader
JP7068983B2 (en) * 2018-09-28 2022-05-17 日立建機株式会社 Work vehicle
CN109250657B (en) * 2018-12-03 2023-08-01 江苏建筑职业技术学院 Steering system of aerial working platform and control method
JP7490478B2 (en) * 2020-07-10 2024-05-27 株式会社小松製作所 Working machine and method for controlling working machine
JP7417485B2 (en) * 2020-07-10 2024-01-18 株式会社小松製作所 Work machines and methods for controlling work machines

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2038465U (en) * 1988-06-02 1989-05-31 单佺 In-situ turning gear for motor vehicles
US5996701A (en) * 1997-12-19 1999-12-07 Komatsu Ltd. Control method and system for construction machine
CN2487628Y (en) * 2000-07-15 2002-04-24 厦工集团三明重型机器有限公司 Steering hydraulic device for refuse compaction vehicle

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6255564A (en) * 1985-09-04 1987-03-11 Nec Corp Logic analyzer with useless data suppressing function
JPH1045014A (en) * 1996-08-07 1998-02-17 Komatsu Ltd Steering device capable of varying control angle of steering wheel
JPH11115780A (en) * 1997-10-15 1999-04-27 Komatsu Ltd Displacement control method of steering pump for work vehicle and its device
US6073442A (en) * 1998-04-23 2000-06-13 Caterpillar Inc. Apparatus and method for controlling a variable displacement pump
DE19931143B4 (en) * 1999-07-06 2004-10-14 Sauer-Danfoss Holding Aps Hydraulic steering device
JP4247986B2 (en) * 2003-12-10 2009-04-02 株式会社小松製作所 Vehicle steering control device
JP4212510B2 (en) * 2004-04-16 2009-01-21 Ｔｃｍ株式会社 Industrial vehicle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2038465U (en) * 1988-06-02 1989-05-31 单佺 In-situ turning gear for motor vehicles
US5996701A (en) * 1997-12-19 1999-12-07 Komatsu Ltd. Control method and system for construction machine
CN2487628Y (en) * 2000-07-15 2002-04-24 厦工集团三明重型机器有限公司 Steering hydraulic device for refuse compaction vehicle

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JP特开平10-45014A 1998.02.17

Also Published As

Publication number Publication date
CN101516715A (en) 2009-08-26
JP4941928B2 (en) 2012-05-30
JP2008155898A (en) 2008-07-10

Similar Documents

Publication Publication Date Title
CN101516715B (en) Steering system for working vehicle
CN101489853B (en) Steering system for working vehicle
EP2098437B1 (en) Steering system for working vehicle
JP4799624B2 (en) Hydraulic drive control device
KR970001723B1 (en) Hydraulic control system for construction machine
US20090320462A1 (en) Hydraulic drive apparatus and hydraulically-driven vehicle
US9334629B2 (en) Open-center hydraulic system with machine information-based flow control
JP6831648B2 (en) Hydraulic drive system
GB2448652A (en) Hydraulic traveling vehicle and method of controlling hydraulic traveling vehicle
KR20150108837A (en) Hydraulic driving device for construction machine
US20230145883A1 (en) Work machine and method for controlling work machine
JP4993575B2 (en) Steering system for work vehicle
KR101955751B1 (en) Construction machine
US11572674B2 (en) Working vehicle
CN110431274B (en) Hydraulic drive device for construction machine
JP7165016B2 (en) hydraulic excavator drive system
JP6936687B2 (en) Work vehicle
JP3666830B2 (en) Hydraulic regeneration circuit for hydraulic machine
JP5755865B2 (en) Hydraulic drive device and work machine equipped with hydraulic drive device
WO2020203884A1 (en) Excavator
JP3462690B2 (en) Construction machine hydraulic circuit
JP2021156063A (en) Hydraulic motion device of construction machine
JPH07197491A (en) Very small revolution-type hydraulic excavator

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
ASS Succession or assignment of patent right

Free format text: FORMER OWNER: TCM CORP.

C41 Transfer of patent application or patent right or utility model
TA01 Transfer of patent application right

Effective date of registration: 20110304

Address after: Tokyo, Japan, Japan

Applicant after: Hitach Construction Machinery Co., Ltd.

Address before: Tokyo, Japan, Japan

Applicant before: Hitach Construction Machinery Co., Ltd.

Co-applicant before: TCM Corp.

C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20120125

Termination date: 20161226