CN110273865A - The gentle regulating device of variable displacement motor discharge capacity - Google Patents

Abstract

The invention discloses a variable motor displacement gentle adjustment device, which includes an oil pump that provides a displacement control valve of the variable motor to control oil pressure. The oil pump is connected to the displacement control valve through a control oil circuit, and a throttle valve is arranged in series on the control oil circuit. And the accumulator, the pressure of the displacement control valve is slowly built up through the throttle valve, and the pressure of the displacement control valve is slowly released through the accumulator. The invention enables the pressure in the displacement control valve of the variable motor to be slowly established and released, avoiding the impact of the mechanical mechanism caused by the excessive instantaneous change range of the displacement of the variable motor under the control of the switch signal; the gentle displacement adjustment device is more reliable Higher and lower cost; the pressure change curve in the displacement control valve is determined by the accumulator charging pressure, volume, and the damping aperture and length of the throttle valve, which is less sensitive to oil viscosity changes caused by different temperatures.

Description

Variable motor displacement smooth adjustment device

technical field

The invention belongs to hydraulic technology, and in particular relates to a gentle adjustment device for variable motor displacement.

Background technique

The hydraulic system of the skid loader includes the working device hydraulic system and the walking hydraulic system. The walking hydraulic system includes the walking pump and the drive motors on the left and right sides. The drive motor drives the wheels on both sides of the skid loader to rotate through the chain. The skid loader The walking and steering of the machine is to enter the hydraulic oil pump into the driving motor through the main walking pump, and realize the steering and walking by adjusting the driving motor to realize the linear speed difference between the wheels on both sides. The drive motor adopts a variable motor, generally there are two motor displacements, one is the standard displacement, and the other is smaller than the standard displacement. When walking in the small displacement mode, the driving wheel rotates faster, which can achieve higher walking speed.

However, the motor displacement is usually controlled by a switch signal, and the motor displacement immediately changes at the moment of switching, resulting in a large walking impact, and the entire vehicle will experience sudden stops or rapid acceleration during operation, which will cause damage to the mechanical mechanism and the entire hydraulic system. Large impact will seriously affect the operating comfort and service life of the machine.

In order to solve this problem, a smooth adjustment device is added to the switching of the motor displacement. At present, there are mainly two structural forms.

One structure is shown in Figure 1a, a parallel orifice 100 and a pressure limiting valve 101 are added between the oil pump 4 and the displacement control valve 2 of the variable motor, wherein the displacement control valve 2 controls the displacement of the variable motor. The oil pump 4 is used as the pressure oil source to control the action of the displacement control valve 2, and is connected to the displacement control valve 2 through the oil circuit. pressure changes. This solution is less practical in actual application, and it is only suitable when the control pressure range is relatively large, and the effect of the components with a relatively large hydraulic volume of the variable mechanism of the variable motor is more obvious, but this kind of application environment is rare. Most variable motors have relatively small changes in the volume of the variable mechanism, and the control pressure is relatively low. In order to obtain a gentler pressure control curve, the diameter of the orifice 100 is required to be small. On the one hand, the smaller the orifice 100 is, the more difficult it is to process; on the other hand, if the orifice is too small, oil passage blockage may easily occur. Therefore, this scheme has great limitations in practical application.

The structure of another gentle adjustment device is shown in Figure 1b. An electric proportional pressure reducing valve 200 is added between the oil pump 4 and the displacement control valve 2 of the variable motor, wherein the displacement control valve 2 controls the displacement of the variable motor. The oil pump 4 is used as the pressure oil source to control the action of the displacement control valve 2, and is connected to the displacement control valve 2 through the oil circuit. The oil pump 4 controls the electric proportional pressure reducing valve 200 through the controller of the hydraulic system to output a proportional ramp signal to obtain a ramp pressure switch. Adjust and control the hydraulic displacement control valve 2 to act. The control pressure obtained by this scheme can be controlled arbitrarily according to the demand, and the flexibility is very large, but the switching process of the variable motor displacement is very short, less than 1 second, and the response speed and stability of the proportional control valve itself can easily increase the certainty of the switching process , and the cost of the electric proportional pressure reducing valve is relatively high. If the device itself does not have a programmable controller, a separate controller needs to be added for this purpose, and the implementation cost is relatively high.

Contents of the invention

The technical problem to be solved by the present invention is to provide a novel variable motor displacement gentle adjustment device, which can make hydraulic The oil is controlled to change smoothly so that the displacement of the variable motor changes slowly, reducing the severe impact on the equipment caused by the sudden change of displacement.

The present invention adopts following technical scheme to realize:

The variable motor displacement gentle adjustment device includes an oil pump that provides the displacement control valve of the variable motor to control the oil pressure. The oil pump is connected to the displacement control valve through a control oil circuit. The pressure of the displacement control valve is slowly built up through the throttle valve, and the pressure of the displacement control valve is slowly released through the accumulator; the control oil circuit is provided with a switch for pressure establishment and release of the displacement control valve reversing valve.

Further, the accumulator is arranged close to the displacement control valve, the throttle valve is arranged close to the oil pump, and the reversing valve is arranged on the control oil circuit between the throttle valve and the oil pump.

Further, the accumulator communicates with the control oil passage through the damping hole.

Further, the reversing valve has at least three oil ports, which are respectively connected to the oil pump, the throttle valve and the oil tank. The reversing valve includes hydraulic oil flowing from the oil pump to the displacement control valve to establish pressure and hydraulic oil from the displacement Two positions of the control valve to release pressure to tank flow.

Preferably, the reversing valve is a two-position three-way electromagnetic reversing valve.

Preferably, the variable motor is a radial piston variable motor or an axial piston variable motor.

Further, the reversing valve also has a cut-off working position that completely cuts off the throttle valve, the oil pump and the oil tank.

Preferably, the variable motor is a radial piston variable motor.

Further, the reversing valve is an electromagnetic proportional control valve.

In the variable motor displacement gentle adjustment device of the present invention, the accumulator, the throttle valve and the reversing valve are integrated on the valve block; they can also be distributed and then connected by pipelines; or integrated in other functional valves block.

The variable motor displacement gentle adjustment device of the present invention inputs the buffered and decompressed control oil into the displacement control valve that controls the displacement of the variable motor, and through the throttle valve, the pressure is slowly established in the displacement control valve to control the oil. It enters the displacement control valve through the reversing valve and the throttle valve in turn, and the displacement of the variable motor also changes slowly with the slow build-up of pressure, avoiding the excessive instantaneous change of the displacement of the variable motor under the control of the switch signal severe mechanical shock. The accumulator is directly connected to the displacement control valve through the control oil circuit, the control oil enters the accumulator through the damping hole, the pressure in the accumulator rises slowly, and the pressure in the displacement control valve builds up slowly following the accumulator. Conversely, due to the existence of the accumulator, the pressure control oil in the accumulator returns to the oil tank through the throttle valve and the reversing valve, the internal control pressure of the accumulator decreases slowly, and then the pressure oil pressure of the displacement control valve is released slowly and smoothly , to achieve smooth switching of the displacement control valve. The time to achieve buffering can be changed by adjusting the diameter and length of the damping hole in the throttle valve, the volume of the accumulator and the charging pressure.

In summary, the variable motor displacement gentle adjustment device of the present invention has the following beneficial effects: the present invention slowly builds and releases the pressure in the displacement control valve of the variable motor through the displacement smooth adjustment device, avoiding the displacement of the variable motor. The impact of the mechanical mechanism caused by the excessive instantaneous change of the volume under the control of the switch signal; the gentle adjustment device of the displacement can not use the electric proportional control element, which has higher reliability and lower cost; the pressure change curve in the displacement control valve It is determined by the accumulator charging pressure and volume, and the damping aperture and length of the throttle valve. It is not sensitive to changes in oil viscosity caused by different temperatures. It can be used on the travel drive motors of construction machinery such as skid steer loaders Applied to other occasions that require variable motor control.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Figures 1a and 1b are structural schematic diagrams of two kinds of variable variable motor gentle adjustment devices in the background art, respectively.

Fig. 2 is a schematic diagram of the hydraulic principle of the variable motor displacement smooth adjustment device in the embodiment.

Labels in the figure: 1-variable motor, 100-throttle hole, 101-pressure limiting valve, 200-electric proportional pressure reducing valve, 2-displacement control valve, 3-valve block, 4-oil pump, 5-reversing valve , 6-switch control signal, 7-accumulator, 8-throttle valve, 9-control oil circuit, 10-return oil circuit.

Detailed ways

Example

Referring to Fig. 2, the variable motor displacement gentle adjustment device in the illustration is a specific embodiment of the present invention, and the variable motor 1 is a travel drive motor applied on a skid steer loader, and adopts a radial piston variable motor or an axial plunger The variable motor is equipped with a displacement control valve 2, which is a piston cylinder or a hydraulic slide valve. The oil pump 4 is connected to the displacement control valve 2 through the control oil circuit 9, and the pressure established by the oil pump 4 controls the pressure of the displacement control valve 2. The movement of the piston cylinder pushes the oil distribution mechanism inside the variable motor 1 to move, so as to realize the displacement change of the variable motor 1 and realize the adjustment of the movement speed of the skid steer loader. The above is the working principle of the displacement adjustment of the variable motor, and the specific internal structure and hydraulic pipeline layout of the variable motor are conventional settings, and will not be repeated in this embodiment.

In this embodiment, by setting a gentle adjustment device on the control oil circuit 9, the displacement of the variable motor 1 can be switched smoothly, reducing the mechanical impact of the variable motor 1 on the equipment caused by the change of displacement.

Specifically, an accumulator 7 and a throttle valve 8 are arranged in series on the control oil passage 9 , the accumulator 7 is arranged close to the displacement control valve 2 , and the throttle valve 8 is arranged close to the oil pump 4 . In the process where the oil pump 4 builds up pressure into the displacement control valve 2 , the hydraulic fluid passes through the throttle valve 8 , so that the pressure inside the displacement control valve 2 changes slowly. At the same time, the accumulator 7 communicates with the control oil circuit through the damping hole, and the accumulator 7 is charged during the pressure build-up process of the displacement control valve 2. When the pressure inside the displacement control valve 2 is released, the accumulator The pressure release in the accumulator 7 controls the hydraulic fluid to return to the oil tank through the throttle valve 8, the internal control pressure of the accumulator 7 decreases slowly, and then the internal pressure of the displacement control valve 2 is released slowly and steadily. No matter whether the internal pressure of the displacement control valve 2 is building up or releasing the pressure, the piston cylinder of the displacement control valve can switch smoothly, which reduces the impact during the switching process of the variable motor speed adjustment.

On the control oil circuit 9, there is also a reversing valve 5 for switching the pressure build-up and release of the displacement control valve. The reversing valve 5 is arranged on the control oil circuit 9 between the throttle valve 8 and the oil pump 4. The reversing valve 5 has three working oil ports, which are respectively connected to the oil pump 4 on the control oil circuit 9 , the throttle valve 8 and connected to the oil tank through the oil return circuit 10 . The reversing valve 5 in this embodiment adopts a two-position three-way electromagnetic reversing valve, including two working positions where hydraulic oil flows from the oil pump to the displacement control valve to build up pressure and hydraulic oil flows from the displacement control valve to the oil tank to release pressure. , the spool of the reversing valve moves to one of the working positions to connect the oil pump 4 with the throttle valve 8, and the working oil port connected to the oil return circuit 10 is closed. The displacement control valve 2; the spool of the reversing valve moves to another working position to connect the throttle valve 8 with the oil return circuit 10, and the working oil port connected to the oil pump 4 is cut off. At this time, the displacement control valve 2 and the accumulator 7 The internal pressure oil slowly returns to the oil tank through the throttle valve 8. The action of the electromagnet of the reversing valve 5 is controlled by the electric signal sent by the control system of the skid steer loader, so that the spool of the reversing valve 5 can switch and move between two working positions.

In practical applications, the accumulator 7, the throttle valve 8 and the reversing valve 5 can be integrated and arranged on the same valve block 3 to form an integral module of a gentle adjustment device, or they can be arranged in a decentralized manner and then connected by pipelines; Or integrated in other functional valve blocks, the oil circuit design inside the valve block belongs to the conventional design according to the selected accumulator, throttle valve and reversing valve, and will not be described in this embodiment.

The skid steer loader to which this embodiment is applied has two driving speeds, that is, the variable motor 1 is a double-displacement variable motor. When the user operates the whole machine, he inputs a switch control signal 6 to the reversing valve 5 by operating the switch button, and the control pressure oil generated by the oil pump 4 enters the throttle valve 8 through the reversing valve 5, and the control pressure oil enters the accumulator through the throttle valve 8. accumulator 7 and displacement control valve 2, the pressure oil gradually enters the accumulator 7, the pressure in the displacement control valve 2 and the control oil circuit 9 rises slowly and steadily, the displacement control valve 2 realizes smooth switching, and the displacement of the variable motor 1 The volume decreases gradually, the piston cylinder of the displacement control valve 2 moves in place, and the pressure limiting valve of the oil pump 4 is triggered, so that the pressure in the control oil circuit and the internal pressure of the displacement control valve 2 is constant, and the speed of the skid steer loader can be increased smoothly, eliminating Heavy mechanical shock.

The user operates the switching button again to input a low-level switch control signal to the reversing valve 5, the spool of the reversing valve moves to switch the working position, and the pressure oil source of the oil pump 4 is cut off. The control pressure oil in the accumulator 7 returns to the oil tank through the throttle valve 8 and the reversing valve 5, the control pressure in the accumulator 7 decreases slowly, and then the pressure oil pressure of the displacement control valve 2 decreases slowly and steadily, and the displacement control valve 2 realizes Switch smoothly until the piston cylinder of the displacement control valve 2 returns to its original position, the displacement of the variable motor 1 increases gently, and the speed of the skid steer loader decreases smoothly, thereby reducing the large mechanical impact caused by the slowing down of the speed.

In theory, it can also be considered to add a working position to the reversing valve 5. After the spool of the reversing valve 5 moves to this working position, all the working oil ports connected to the reversing valve 5, the throttle valve 8, the oil pump 4 and the fuel tank are all Cut off, the pressure of the displacement control valve 2 can be maintained through the accumulator 7, at this time, the piston cylinder of the displacement control valve 2 can be kept at any position between the two limit positions, and the displacement of the variable motor 1 can be realized steplessly Adjustment switching, this method is only suitable for radial piston variable motors, and it is necessary to ensure the sealing performance of each connection part of the control oil circuit. It is also possible to use an electromagnetic proportional control valve for the reversing valve 5 to realize precise control of the position of the spool.

The above is only one of the specific implementations of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principles of the present invention should also be regarded as the protection scope of the present invention.

Claims (9)

1. The variable motor displacement gentle adjustment device, including an oil pump that provides the displacement control valve of the variable motor to control the oil pressure, and the oil pump is connected to the displacement control valve through the control oil circuit, and it is characterized in that: the control oil circuit is arranged in series There is a throttle valve and an accumulator, the pressure of the displacement control valve is slowly established through the throttle valve, and the pressure of the displacement control valve is slowly released through the accumulator; the control oil circuit is equipped with a switching displacement control Valve pressure build-up and release directional valve. 2. The variable motor displacement gentle adjustment device according to claim 1, the accumulator is arranged close to the displacement control valve, the throttle valve is arranged close to the oil pump, and the reversing valve is arranged between the throttle valve and the oil pump. between the control oil. 3. The variable motor displacement gentle adjustment device according to claim 2, wherein the accumulator communicates with the control oil circuit through a damping hole. 4. The variable motor displacement gentle adjustment device according to claim 3, the reversing valve has at least three oil ports, which are respectively connected to the oil pump, the throttle valve and the oil tank, and the reversing valve includes hydraulic oil from the oil pump The flow to the displacement control valve builds up the pressure and the hydraulic oil flows from the displacement control valve to the oil tank to release the pressure. 5. The variable displacement motor displacement gentle adjustment device according to claim 4, wherein the reversing valve is a two-position three-way electromagnetic reversing valve. 6. The device for gently adjusting the displacement of a variable motor according to claim 4, wherein the variable motor is a radial piston variable motor or an axial piston variable motor. 7. The variable displacement motor displacement gentle adjustment device according to claim 3, the reversing valve also has a cut-off working position that cuts off the throttle valve, the oil pump and the oil tank. 8. The device for gently adjusting the displacement of a variable motor according to claim 7, wherein the variable motor is a radial piston variable motor. 9. The variable motor displacement gentle adjustment device according to claim 3, wherein the reversing valve is an electromagnetic proportional control valve.