JPH0718703A - Operating lever for construction machine - Google Patents

Abstract

PURPOSE:To make a damper connected to an operating lever generate optimum damping force in accordance with changes in the temperature or the like of working fluid in a cylinder. CONSTITUTION:A damper 13 for a travel lever 11 is equipped with a piston assembly that makes slide movement inside a cylinder 16, interlocking with operation of a damper lever 14. A plurality of communicating holes bored in the direction of axis are provided to a plate and a holder that are provided to the piston assembly. As the holder is moved in reciprocation at a specified angle, the area of opening in a restrictor changes with overlapping parts in the communicating holes varied. A sensor 29 for detecting the temperature of working fluid is provided in the cylinder while a sensor 30 for detecting the operation angle of the travel lever 11 is mounted to a pivot 12. Signals from both of the sensors are taken into a control part, and an optimum area for the opening in the restrictor is calculated and the cylinder is turned thereby, making the holder turn relatively against the plate. Thereby, the degree of overlapping in the communicating holes can be varied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating lever device for operating a hydraulic actuator in a hydraulic excavator and other construction vehicles.

[0002]

2. Description of the Related Art As a construction vehicle, for example, a hydraulic excavator is
A hydraulic motor is provided as an actuator for running the vehicle. A control valve is provided to control the direction and flow rate of the pressure oil to the hydraulic motor, and a traveling lever is provided as an operation lever in the driver's seat in order to operate the control valve. When this travel lever is operated, the supply direction and supply amount of the pressure oil to the hydraulic motor change according to the operation direction and the operation amount, and the vehicle moves forward or backward,
And the running speed can be controlled.

FIG. 5 shows a conventional traveling lever device.
In the figure, 1 is a control valve, 2 is a traveling lever, respectively, and a driver can operate the control valve 1 by tilting the traveling lever 2. Reference numeral 3 is a damper for stabilizing the traveling lever 2 that controls the control valve 1. The damper 3 has a damper lever 5 which rotates about a rotation shaft 4 thereof in response to an operation of the traveling lever 2. A piston rod 6 is connected to the damper lever 5, and the piston rod 6 operates. It extends inside a cylinder 7 in which oil is enclosed, and its tip is connected to a piston 8 that slides along the inner surface of the cylinder 7. Further, the piston 8 is formed with a throttle portion 9 which allows the working oil to flow between the two chambers 7a and 7b in the cylinder 7 which is partitioned by the piston 8.

With the above structure, when the traveling lever 2 is operated to operate the control valve 1, the damper lever 5 is rotated accordingly and the piston 8 slides along the cylinder 7. Then, the hydraulic oil flows through the throttle portion 9, but the flow resistance generated at this time exerts a damping action for the operation of the traveling lever 2. Therefore, when the traveling lever 2 is stopped at a certain angle position, the damping action of the damper 3 keeps the traveling lever 2 in that position in a stable state without moving excessively.

[0005]

By the way, the damper 3 uses hydraulic oil, and the damping force is exerted by the flow resistance when the hydraulic oil passes through the throttle portion 9.
Hydraulic fluid changes its flow resistance depending on its viscosity,
When the oil temperature is low, the resistance becomes too large, and when the oil temperature rises, the flow resistance decreases accordingly, which causes a problem that the damping action of the damper 3 is not stable. In particular, as in work in cold regions or winter, the viscosity of the hydraulic oil of the damper 3 increases significantly and the damping force becomes too large, and the travel lever 2 is used to stop the vehicle from the full stroke position. It may take a considerably long time to return when returning 2 to the neutral position, and there is a drawback that the operability during traveling deteriorates. Further, when the oil temperature rises, the vibration is transmitted to the traveling lever 2 even if a slight vibration acts on the traveling lever 2.
Delicately moves to cause hunting of the control valve 1 and the running stability of the vehicle is lost, which causes a problem such as a so-called running jerky vibration state.

Further, the operating levers such as the traveling lever 2 are normally in the neutral position in the vertical state and are tilted to the front side or the front side of the driver's seat. It does not have to be constant. For example, in the vicinity of the neutral position of the operating lever, the damping action is lowered to some extent so that fine operation is possible, and in the side close to the full operating position from the intermediate position, a high damping action is provided to improve the stability of the operating lever. In some cases, it may be preferable to generate. In addition to this, for example, it may be better to change the damping force due to the damping action when the operation lever is operated alone and when two or more kinds of operation levers are operated in combination. However, the damper of the related art cannot change the damping force according to the operation status of the operation lever.

The present invention has been made in order to solve the problems of the prior art as described above, and the damping force by the damper connected to the operation lever is changed according to the temperature state of the working oil in the cylinder. The objective is to make changes that are optimal.

[0008]

In order to achieve the above-mentioned object, the present invention provides an operating lever for operating a control valve for controlling a hydraulic actuator of a construction vehicle, and a throttle portion in a cylinder in which a working fluid is sealed. A piston provided with is slidably mounted, the piston is slidably displaced in a cylinder in conjunction with the operation lever, and a damping action is exerted by the throttle portion. The throttle provided on the piston sliding in the cylinder is a variable throttle, and a temperature sensor for detecting the temperature of the working fluid is provided, and the opening area of the throttle is changed based on at least the temperature detected by the temperature sensor. It is characterized in that the control means is provided.

[0009]

[Operation] Construction vehicles usually work outdoors, so there are large differences in temperature conditions depending on the working environment.
For this reason, the viscosity of the working fluid of the damper changes greatly depending on the temperature. Therefore, measure the oil temperature of this working fluid,
The opening area of the throttle is changed according to the oil temperature. That is, when the oil temperature is high, the viscosity decreases, so the opening area of the throttle is made small, and when the oil temperature is low and the viscosity is high, the opening area of the throttle is made large. by this,
Even if there is a change in oil temperature, the damping force by the damper will be almost constant, the operation lever will not move more than necessary, will not become too heavy, and the response will be delayed when returning to the neutral position. There is no inconvenience.

From the viewpoint of operability, it may be preferable that the same damping force is not generated in the entire range of the stroke of the operating lever, but that the damping force is changed according to the angle of the operating lever. A preferable characteristic of the change in damping force according to the angle of the operating lever is recorded in advance in the control means, and the aperture opening may be changed depending on the operation angle position of the operating lever as well as the change in the aperture opening based on the oil temperature. If so, the operability of the operating lever is further improved. It is also possible to change the aperture area of the diaphragm when operating the operating lever independently and when operating the operating levers in combination.

[0011]

Embodiments of the present invention will be described below with reference to FIGS. First, in FIG. 1, 10 is a control valve,
11 indicates traveling levers as operating levers,
One end of the traveling lever 11 is connected to the rotating shaft 12,
It can be tilted back and forth about the pivot shaft 12. The travel lever 11 is always held in a vertical neutral position by the action of a return spring (not shown), and the driver operates the grip 11a at the tip of the travel lever 11 to tilt it forward. Then, when the vehicle moves forward and tilts to the front side, the vehicle moves backward and travels at an output torque corresponding to the tilt angle of the travel lever 11.

A damper 13 is provided to ensure the stability of the traveling lever 11. This damper 13
As shown in FIGS. 2 and 3, a damper lever 14 is provided, one end of the damper lever 14 is connected to an end portion of the traveling lever 11 via a rotating shaft 12, and the other end is engaged with a piston rod 15. I am fit. Piston rod 15
Is extended into a cylinder 16 in which hydraulic oil is sealed, and is connected to a piston assembly 17 that divides the inside of the cylinder 16 into two chambers 16a and 16b. The piston assembly 17 includes a plate portion 18 formed of an annular plate body connected and fixed to the piston rod 15, and a holder portion 1 mounted so that the plate portion 18 is sandwiched.
9 and 9. The holder portion 19 is formed with a through hole 19a through which the piston rod 15 can be inserted, and an annular recessed portion 19b formed at an intermediate portion in the thickness direction of the holder portion 19. The plate portion 18 is connected to the piston rod 15. In this state, it is slidably accommodated in the recess 19b. Further, one or a plurality of ridges 20 are provided on the outer peripheral surface of the holder portion 19 in the axial direction thereof.
Is a groove 21 formed in the inner surface of the cylinder 16 in the axial direction.
Is engaged with. Therefore, the holder portion 19 becomes rotatable relative to the plate portion 18, and the cylinder 16
However, it is slidable in the axial direction along with the plate portion 18 in the cylinder 16.

With the above-described structure, when the traveling lever 11 is operated, the control valve 10 is actuated to change the supply direction and the supply amount of the pressure oil to the hydraulic motor for traveling, so that the vehicle is driven. Moves forward or backward, and its traveling speed is controlled. At this time, depending on the operation of the traveling lever 11,
The damper lever 14 rotates, the piston rod 15 advances and retreats with respect to the cylinder 16, and the piston assembly 17
Slide along the inner surface of the cylinder 16. Here, the piston assembly 17 has two chambers 16 as described later.
A throttle portion that communicates a and 16b is formed, and the cylinder 16 when the piston assembly 17 is displaced is formed.
Due to the flow resistance of the hydraulic oil inside, a damping action for the operation of the traveling lever 11 is exerted. Then, when the traveling lever 11 is held at a predetermined angular position, even if there is vibration of the vehicle or the like, the damper 13 exerts a damping action, and there is no inconvenience that the traveling lever 11 moves unintentionally. The running stability of the vehicle is ensured.

The throttle portion formed in the piston assembly 17 and connecting the two chambers 16a and 16b in the cylinder 16 is a variable throttle whose opening area changes. That is, the plate portion 18 has a communication hole 2 penetrating in the axial direction.
2 is provided at a plurality of locations, and the holder portion 19 is also provided with a plurality of communication holes 23 at a plurality of locations. These communication holes 22
Although and 23 are not essential requirements, it is preferable that their numbers and sizes be the same. Since the plate portion 18 and the holder portion 19 can be rotated relative to each other, when the holder portion 19 is reciprocally rotated by a predetermined angle, the overlapping portions of the communication holes 22 and 23 are changed. . Two
Since the communication passage between the chambers 16a and 16b is a portion where both the communication holes 22 and 23 overlap, the opening area of the throttle portion is changed by rotating the plate portion 18. In order to rotate the holder portion 19, the cylinder 16 can be rotated on the support block 24 via the slide member 24a, and a stopper portion 16c is formed at an end of the cylinder 16 to slide the stopper portion 16c. By engaging with the end wall of 24a, it is supported so as not to be displaceable in the axial direction, and a pivot pin 25 is provided on the outer surface of this cylinder 16 so as to project. And this rotation pin 25
Drive lever 26 is connected to the drive lever 2
The other end of 6 is connected to a driving means 27 such as a stepping motor or an electromagnetic valve. Therefore, when this driving means 27 is operated, the holder portion 19 rotates together with the cylinder 16 and the communicating holes 22 and 23 are used. The opening area of the formed diaphragm portion changes. Further, together with the cylinder 16, the holder portion 19
In order to hold the piston rod 15 so as not to follow it when the
A rectangular detent portion 15a is formed on the inner side of the ridge, and a slide guide 28 is inserted into the detent portion 15a.

The opening area of the throttle portion formed by the communication holes 22 and 23 is changed according to the oil temperature of the working oil enclosed in the cylinder 16, and also depending on the operation angle position of the traveling lever 11. The opening area is changed.
For this purpose, an oil temperature sensor 29 for hydraulic oil is provided in the cylinder 16, and an angle sensor 30 for detecting the operation angle of the traveling lever 11 is attached to the rotary shaft 12. Then, as shown in FIG. 4, the signals from the oil temperature sensor 29 and the angle sensor 30 are taken into the control unit 30, and from the oil temperature and the angle of the traveling lever 11, the optimum throttle opening area is obtained. Is calculated, a signal is given to the driving means 27, the driving lever 26 is rotated by a predetermined angle, and thereby the cylinder 16 is rotated, whereby the piston assembly 1
By rotating the holder portion 19 constituting 7 relative to the plate portion 18, the overlapping degree of the communication holes 22 and 23 is changed so that the optimal aperture opening area determined by the control portion 31 is obtained. I am trying.

First, the opening area of the throttle portion is changed according to the oil temperature of the hydraulic oil. The viscosity of the hydraulic oil sealed in the cylinder 16 changes depending on the oil temperature, and the viscous resistance when passing through the throttle changes. Therefore, the control unit 31 is provided with an oil temperature-throttle opening conversion unit 32, and the oil temperature sensor 29 is connected to the oil temperature-throttle opening conversion unit 32. The oil temperature-throttle opening conversion unit 32 has a viscosity change characteristic (graph T in FIG. 4) with respect to the oil temperature recorded beforehand according to the type of hydraulic oil sealed in the cylinder 16, and the oil temperature sensor 29.
The opening area of the throttle portion is controlled in accordance with the change in viscosity so that a constant damping action is always exhibited based on the signal from. That is, when the oil temperature of the hydraulic oil is low, the degree of overlap between the communication holes 22 and 23 is increased to increase the opening area of the throttle portion, and when the oil temperature is high, the communication hole is increased. 22 and 23 are offset from each other to reduce the opening area. by this,
Even if the oil temperature changes, a constant damping action will always be exhibited.

Also, the damping action is adjusted by changing the opening area of the diaphragm portion according to the operating angle of the traveling lever 11. For this purpose, the control unit 31 includes an angle-diaphragm aperture conversion unit 33, and the angle-diaphragm aperture conversion unit 3 is provided.
An angle sensor 30 is connected to 3. That is, in the entire stroke of the traveling lever 11, in the vicinity of the neutral position, the stroke end position, the intermediate position thereof, and the operation direction, the stability of the operating force applied to the traveling lever 11 during operation is improved. There is a difference. Moreover,
From the viewpoint of operability, it is necessary to weaken the damping force to some extent when the running needs to be controlled minutely, and to increase the damping force when running stability is prioritized. In this way, from the viewpoint of the ergonomics of the driver and the relative relationship between the traveling stability and the operability, the traveling lever 1
It is also necessary to adjust the damping force according to the angular position of 1.

Therefore, for example, it may be necessary for the running of the vehicle to have the characteristics shown by the graph S in FIG. That is, the damping force of the former is made stronger in the forward direction, that is, when the traveling lever 11 is tilted forward, and in the backward direction, that is, when the traveling lever 11 is tilted toward the front side. Further, in the vicinity of the neutral position of the traveling lever 11 and the full operation position, the damping force is weakened in consideration of operability, and in the side closer to the full operation position from the intermediate position, the damping force is weakened in consideration of traveling stability. To control. Of course, if the vibration of the vehicle is strong or weak in the entire stroke of the operation angle of the traveling lever 11 due to the characteristics of the vehicle, the damping force is made particularly strong in accordance with the strength of this vibration, that is, in the position where the vibration is severe. Such control is also performed.

Here, the control data in the angle-diaphragm aperture conversion unit 33 is not fixed, and a plurality of types of control data are provided in advance according to the work environment, the type of work, etc., depending on the work situation. It is also possible to change the control characteristics as appropriate, or to give each vehicle a control characteristic unique to each vehicle. In this way, if the optimum damping action is exerted according to the working situation, the characteristics of the vehicle, etc., the running stability and operability are significantly improved.

As described above, the oil temperature-throttle opening conversion section 32
Thus, the adder 34 adds the data regarding the optimum throttle opening area calculated according to the oil temperature and the data regarding the optimum throttle opening area calculated according to the angle of the traveling lever 11 by the angle-throttle opening conversion unit 33. Then, the output signal from the adder 34 is input to the servo circuit 35, and the drive signal is given to the drive means 27 from the servo circuit 35. As a result, the damper 1 is affected by the oil temperature of the hydraulic oil.
The damping force of the damper 13 of the traveling lever 11 does not change, and the damping force of the damper 13 of the traveling lever 11 decreases at an operating angle that requires more operability because of the relationship between the operability and stability of the traveling lever 11. In the operation angle region where the force is small and the stability is required, the damping force of the damper 13 is increased to cause the traveling lever 11 to slightly move due to vibration or the like, which is unintended. As a result, running jerky and the like will not occur.

In the above-described embodiment, the traveling lever of the vehicle has been described, but other operating levers other than this can have the same structure. Also,
The operation lever may be a foot-operated type as well as a manually operated type. Further, although the opening area of the throttle portion is changed based on the oil temperature of the hydraulic oil in the cylinder and the operation angle of the traveling lever, the point is to control the opening area of the throttle portion at least by the oil temperature. In addition to the oil temperature and the operating angle of the travel lever, it is also possible to change the opening area of the throttle depending on whether the operating lever is operating independently or in combination. Is.

[0022]

As described above, according to the present invention, the throttle portion of the piston slidably provided in the cylinder of the damper is a variable throttle, and the temperature sensor for detecting the temperature of the working fluid is provided. Since the control means is provided to change the opening area of the throttle part based on the temperature detected by the temperature sensor, the damping force by the damper will be almost constant even if the oil temperature changes, and the operating lever will be more than necessary. It is easy to move, and the stability of the vehicle is not lost due to running jerky, or it becomes too heavy and does not interfere with minute movements, and there is a response when returning to the neutral position. There are no inconveniences such as delays, operability is good, and operation stability is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of an operation lever device showing an embodiment of the present invention.

FIG. 2 is a sectional view of a damper.

FIG. 3 is a sectional view taken along line XX of FIG.

FIG. 4 is an explanatory diagram of a configuration of a mechanism for varying the opening area of a diaphragm unit.

FIG. 5 is a configuration explanatory view of an operation lever device in the related art.

[Explanation of symbols]

 10 Control Valve 11 Travel Lever 13 Damper 14 Damper Lever 15 Piston Rod 16 Cylinder 17 Piston Assembly 18 Plate Part 19 Holder Part 22, 23 Communication Hole 29 Oil Temperature Sensor 30 Angle Sensor 31 Control Part 32 Oil Temperature-Throttle Opening Conversion Part 33 Angle- Aperture aperture converter

Claims (2)

[Claims] 1. An operating lever for actuating a control valve for controlling a hydraulic actuator of a construction vehicle, and a piston having a throttle portion slidably mounted in a cylinder in which a working fluid is sealed, and interlocking with the operating lever. Then, the piston is slidably displaced in the cylinder so that a damping force is generated by the throttle part.In this damper, the throttle part provided on the piston sliding in the cylinder serves as a variable throttle and operates. An operating lever device for a construction vehicle, comprising a temperature sensor for detecting a temperature of a fluid, and a control means for changing an opening area of a throttle portion based on at least a temperature detected by the temperature sensor. 2. The operation lever is provided with an angle detector for detecting a rotation angle thereof, and the control means is configured to change the opening area of the throttle portion by the operation angle of the operation lever together with the temperature of the working fluid. The operation lever device for a construction vehicle according to claim 1, wherein: