CN101413838A - Apparatus for measuring plunger sub-oil film viscous friction - Google Patents

Abstract

The invention discloses a device for measuring viscous friction force of an oil film on a plunger pump of a plunger pump. Including cylinder, sensing rod, connecting rod, fastening screw, sensor cable, friction sensor, fixing nut, plunger bushing, spring collar, guide rod and one-way valve assembly. The guide rod and the bush are connected together by the spring collar to form a floating bush assembly supported by static pressure. The three-dimensional viscous force of the oil film is sensed by the sensing rod and transmitted to the oil film through the more rigid connecting rod. The friction sensor, the cable of the friction sensor is led to the center of the cylinder through the wire groove on the cylinder, and is transmitted out through the main shaft of the plunger pump. This structure makes reasonable use of the gap between the plunger chambers on the cylinder body, so that the relatively large friction sensor has enough installation space, reliable structure, stable performance, and ingenious design and application of the overall mechanical structure , so that the structure is compact and the volume is reduced.

Description

A device for measuring viscous friction force of plunger pair oil film

technical field

The invention relates to an oil film viscous friction measuring device for a key friction pair of an axial plunger pump, in particular to a plunger pair oil film viscous friction measuring device.

Background technique

The axial piston pump/motor is one of the most important power components in the hydraulic field, and its plunger pair is the working area where the reciprocating motion of the plunger generates oil suction and pressure. The friction and lubrication performance of the oil film of the plunger pair directly determines the performance of the plunger pump. However, due to the narrow space of the cylinder where the plunger cavity is located, and the oil film viscous friction of the plunger pair exists in both axial and circumferential directions of the plunger, the viscous friction of the oil film requires a special structure to sense forces in all directions. The traditional experimental methods mainly include the following methods:

1. Static single plunger structure. It is to process a single plunger cavity separately, install it statically on the test bench, and the state of the oil passing through the plunger in a certain state in the plunger cavity can be detected for research. Both Zhejiang University of Technology and the University of Missouri Columbia in the United States have built such experimental devices. Such a device is very different from the actual structure of the plunger pump, and basically cannot realize the function of the plunger pump, and only conducts qualitative research on a single component. The limitations are relatively large.

2. Semi-dynamic single plunger structure. A plunger cavity is still processed separately and fixed on the frame, and the plunger can be driven to slide in the plunger cavity by a crank connecting rod and other mechanisms, thereby realizing the reciprocating motion of the plunger to simulate the working condition of the plunger. Such an experimental device has been developed at RWTH Aachen University in Germany. But because it is only the work of a single plunger, and there is no rotation effect of the plunger, there is still a certain gap with the work of the actual plunger pump motor.

3. Approximate dynamic single plunger structure, based on the idea of a model pump, adopts a single plunger, a single plunger is fixed, and the swash plate rotates to drive the plunger to slide in the plunger cavity, and the column is driven by the friction of the swash plate. The rotation effect of the plug has been added, so the working conditions are more realistic. Purdue University in the United States has developed such a test bench. However, the experimental device still has certain limitations due to failure to consider the mutual disturbance between the plungers and the flow distribution structure.

With the development of micro-sensor technology, based on the idea of model pumps, it is urgent to develop a new type of test technology for the friction test of the plunger oil film of the plunger pump without changing the structure of the plunger pump. The device makes it possible to test the friction force of the plunger auxiliary oil film in all directions.

Contents of the invention

The object of the present invention is to provide a kind of plunger auxiliary oil film viscous friction force measurement device, make the plunger bushing float by hydrostatic support so as to be able to sense the viscous friction force from all directions of the oil film, and design the sensing force of three-dimensional force sensor The device utilizes the gap between the plunger chambers to measure the frictional force, and ensures that the original working structure and function of the plunger pump remain unchanged.

The technical solution adopted by the present invention to solve its technical problems is:

Including cylinder, sensing rod, connecting rod, sensor cable, friction sensor, plunger bushing, spring collar, guide rod and check valve; The collar connects the guide rod and the plunger bushing together to form a floating bushing assembly supported by static pressure, in which the guide rod and the plunger chamber have an interference fit, and the plunger bush and the spring collar are opposite to the guide rod Floating, the ball head of the sensing rod fixed on one end of the connecting rod with a fixing nut extends into the sensing hole of the plunger bushing to sense the viscous friction force, and the other end of the connecting rod is fixed on the friction by the fastening screw at the same time On the force sensor, the friction sensor is installed in the installation groove opened on the cylinder body, and the oil drawn from multiple plunger chambers equipped with check valves supports the high-pressure oil in the support groove of the plunger bushing.

The outer surface of the distribution end surface of the cylinder body 1 is a plane or a concave spherical surface.

The friction sensor is a three-dimensional force, two-dimensional force, or one-dimensional force sensor, and the sensing rod is a three-dimensional force, two-dimensional force, or one-dimensional force sensing rod.

The plunger bushing has multiple static pressure support windows, and the high-pressure oil drawn from the plunger chamber on the cylinder supports the plunger bushing.

The number of plunger cavities on the cylinder is 1-11.

The beneficial effects that the present invention has are:

Viscous friction force in all directions of the oil film of the plunger pair of the plunger pump is measured by the cylinder body of the present invention without substantially changing the structure of the plunger pump. The present invention is produced with the deepening of people's research on the plunger pump motor, which enables people to further study the friction and lubrication of the plunger pair of the plunger pump motor, so that the actual working conditions can be simulated in the plunger pump motor Carry out the performance test of the friction force of the plunger pair. The present invention adopts the design of mechanical principles and has reliable performance; the ingenious design and application of the overall mechanical structure makes the structure compact and the volume smaller.

Description of drawings

Figure 1 is the general installation diagram of the plunger pair friction test device.

Fig. 2 is a sectional view of the plunger pair friction testing device.

Fig. 3 is an assembly diagram of the test sensing part of the plunger pair friction test device.

Fig. 4 is a schematic diagram of the hydrostatic support oil supply circuit of the plunger pair friction test device.

Fig. 5 is a schematic diagram of the three-groove oil supply structure of the floating bush of the plunger pair friction test device.

In the figure: 1. Cylinder body, 2. Induction rod, 3. Connecting rod, 4. Fastening screw, 5. Sensor cable, 6. Friction sensor, 7. Fixed nut, 8. Plunger bushing , 9. Spring collar, 10. Guide rod, 11. Check valve.

Detailed ways

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

As shown in Fig. 1, Fig. 2 and Fig. 3, the present invention includes a cylinder body 1, a sensing rod 2, a connecting rod 3, a fastening screw 4, a sensor cable 5, a friction sensor 6, a fixing nut 7, a column Plug bushing 8, spring collar 9, guide rod 10 and one-way valve 11; in the plunger chamber of cylinder 1, the guide rod 10 and plunger bushing 8 are linked together by spring collar 9 A floating bushing assembly supported by static pressure is formed. The guide rod 10 in the floating bushing assembly is in interference fit with the rear end of the plunger cavity, and the plunger bushing 8 and the spring collar 9 can float relative to the guide rod 10. Moreover, the bosses of the spring collar 9 and the guide rod 10 are used to mutually limit the maximum displacement of the floating. Therefore, the floating plunger bushing 8 can be driven to float by the axial and radial viscous friction force of the oil, so it can sense the axial and radial viscous friction force generated by the plunger movement and the oil, and use the fixed screw The cap 7 is fixed on the connecting rod 3. The ball head of the sensing rod 2 extends into the sensing hole of the plunger bushing 8 to sense the viscous friction force. The connecting rod 3 is fixed on the friction sensor 6 by the set screw 4 at the same time. On the surface, the friction force can lead the viscous friction force signal from multiple directions out of the wire groove of the cylinder body 1 by the wire. The friction sensor 6 and the connecting rod 3 are fixed in the mounting groove provided between the two plunger cavities on the cylinder body 1 by the set screw 4 . As shown in FIG. 4 , the oil introduced from a plurality of plunger chambers equipped with one-way valves 11 supports the high-pressure oil in the support groove of the plunger bushing 8 .

In order to ensure that the plunger bushing 8 can be located in the center of the plunger chamber of the cylinder body 1, a plurality of hydrostatic support grooves are opened on the plunger bushing 8, and the oil from several different plunger chambers The liquid is transmitted to each static pressure tank, because the oil pressure in each plunger chamber changes alternately, so the oil drawn from multiple plunger chambers with different phases ensures that at least one plunger chamber The oil is high-pressure, and then the oil in the high-pressure plunger cavity is introduced into the static pressure support groove of the plunger bushing 8 through the check valve, so that the plunger bushing 8 is forced to center with high-pressure oil, so that the plunger The bushing 8 is in a floating state and can sensitively sense the change of viscous friction force from the oil in the plunger cavity.

The outer surface of the distribution end surface of the cylinder body 1 is a plane or a concave spherical surface.

The friction sensor 6 is a three-dimensional force, two-dimensional force, or one-dimensional force sensor; the sensing rod 2 is a three-dimensional force, two-dimensional force, or one-dimensional force sensing rod.

The plunger bushing 8 has a plurality of static pressure support windows, and the high-pressure oil drawn from the plunger chamber on the cylinder body 1 supports the plunger bushing.

The number of plunger cavities on the cylinder is 1-11.

As shown in Figure 2, Figure 3, and Figure 4, in the plunger chamber of the cylinder, the guide rod and the plunger bushing are connected together by a spring collar to form a floating bushing assembly supported by static pressure. The guide rod in the bush assembly and the rear end of the plunger cavity are interference fit, the plunger bush and the spring collar can float relative to the guide rod, and the bosses of the spring collar and the guide rod are used to limit the maximum floating displacement. Therefore, the floating plunger bushing can be driven to float by the axial and radial viscous friction force of the oil. The plunger bushing can sense the axial and radial viscous friction force generated by the plunger movement and the oil, and use The fixed nut is fixed on the connecting rod, and the ball head of the sensing rod extends into the sensing hole of the plunger bush to sense the viscous friction force. The connecting rod is fixed on the friction sensor by the set screw at the same time, and the friction force can be The viscous friction signals from multiple directions are drawn out from the wire groove of the cylinder by the wires. As shown in Figure 1, the friction sensor and connecting rod are fixed by set screws in the installation groove opened between the two plunger cavities on the cylinder body. This groove makes reasonable use of the effective space between the plunger cavities, so It is guaranteed that the test can be carried out on-line without changing the structure of the plunger pump. Figure 3 is the assembly diagram of the three-dimensional model of the entire measurement structure. A connecting rod with sufficient rigidity is designed to ensure that the force induced by the sensing contact can be accurately transmitted to the sensor. Moreover, the design of the entire connection structure cleverly utilizes the fan-shaped gap between the two plunger cavities on the two cylinder bodies, making the structure compact, stable and reliable. It can be installed as a whole in the effective space on the cylinder body, and the effect after installation is shown in Figure 1.

As shown in Figure 5(a) and Figure 5(b), in order to ensure that the plunger bushing can be located in the center of the plunger cavity of the cylinder body, multiple hydrostatic support grooves are opened on the plunger bushing , the introduction of high-pressure oil can support the plunger bushing in a floating state. As shown in Figure 4, the oil drawn from multiple different plunger chambers is transferred to each static pressure tank, because the oil pressure in each plunger chamber alternately changes from high to low, so it is drawn from multiple different The oil in the plunger chambers of the phases ensures that the oil in at least one plunger chamber is high-pressure, and then the oil in the high-pressure plunger chambers is introduced into the hydrostatic support groove of the plunger bushing through the check valve, so that The plunger bushing is forced to center with high-pressure oil, so that the plunger bushing is in a floating state, and can sensitively feel the change of viscous friction force from the oil in the plunger cavity.

Claims (5)

1. A plunger auxiliary oil film viscous friction measuring device, characterized in that it includes a cylinder body (1), a sensing rod (2), a connecting rod (3), a sensor cable (5), a friction sensor ( 6), plunger bushing (8), spring collar (9), guide rod (10) and check valve (11); (9) Connect the guide rod (10) and the plunger bushing (8) together to form a floating bushing assembly supported by static pressure, wherein the guide rod (10) and the plunger cavity are interference fit, and the plunger bushing The sleeve (8) and the spring collar (9) float relative to the guide rod together, and the ball head of the induction contact rod (2) fixed on one end of the connecting rod (3) with the fixing nut (7) extends into the plunger lining The viscous friction is sensed in the sensing hole of the sleeve (8), and the other end of the connecting rod (3) is fixed on the friction sensor (6) by the fastening screw (4) at the same time, and the friction sensor (6) is installed on the cylinder In the mounting groove provided on the body (1), the oil from a plurality of plunger chambers equipped with check valves (11) supports the high-pressure oil in the support groove of the plunger bushing (8). 2. A plunger auxiliary oil film viscous friction measuring device according to claim 1, characterized in that: the outer surface of the distribution end surface of the cylinder (1) is a plane or a concave spherical surface. 3. A plunger auxiliary oil film viscous friction measuring device according to claim 1, characterized in that: the friction sensor (6) is a three-dimensional force, two-dimensional force, or one-dimensional force sensor, and the sensing touch The rod (2) is a sensing rod for three-dimensional force, two-dimensional force, and one-dimensional force. 4. A plunger auxiliary oil film viscous friction measuring device according to claim 1, characterized in that: the plunger bushing (8) has a plurality of static pressure support windows, which are controlled by the cylinder (1) The high-pressure oil drawn from the plunger cavity supports the plunger bushing. 5. The device for measuring viscous friction force of the plunger auxiliary oil film according to claim 1, characterized in that: the number of plunger cavities on the cylinder is 1-11.

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