Bivariate plunger pump control mechanism piston displacement measuring device and piston detection method

Abstract

The present invention relates to a piston displacement measurement and detection method for a control mechanism of a piston pump, and particularly to a piston displacement measurement device and a piston detection method for a control mechanism of a double-variable piston pump, which solve the technical problems of being unable to directly measure the piston displacement of a high-pressure oil cylinder of the control mechanism, poor interchangeability of the control mechanism, long debugging time of the product, and low first-pass rate of the product. The piston displacement measurement device provided by the present invention includes a bottom plate, a mounting plate, a pin block, a positioning pin, a positioning ring, an extended dial rod, a measuring dial, and a dial frame. The measuring dial is connected to the piston through the pin block, converting the invisible displacement amount into a highly visible visual value, with fast response and strong visibility, facilitating the debugging and fault analysis of the control mechanism. The piston detection method adjusts the initial position of the control mechanism piston by measuring the piston displacement measurement accuracy and the centering accuracy, and can independently debug the control mechanism before product assembly.

Description

Technical Field

[0001] The present invention relates to a piston displacement measurement and detection method for a control mechanism of a piston pump, and particularly to a piston displacement measurement device and a piston detection method for a control mechanism of a double-variable piston pump. Background Art

[0002] The control mechanism controls the flow rate of the double-variable piston pump by controlling the swash plate inclination angle of the double-variable piston pump. Among them, the displacement of the piston in the high-pressure oil cylinder of the control mechanism determines the magnitude and direction of the swash plate inclination angle. The middle position of the piston displacement is the basic position for control, and the accuracy of both determines the output characteristics of the bi-directional variable piston pump. Therefore, the accuracy requirement for the displacement of the oil cylinder piston in the control mechanism is extremely high.

[0003] If the measurement of the oil cylinder piston displacement is inaccurate, there will be phenomena such as flow output at the middle position of the double-variable piston pump and inconsistent flow outputs of the piston pump when the swash plate is at two maximum inclination angles, which will make the working state of the hydraulic transmission mechanism asymmetric and ultimately cause the entire hydraulic transmission system to fail to work. Therefore, it is necessary to detect the piston displacement and centering of the oil cylinder in the control mechanism in order to meet the design requirements through adjustment and satisfy the product use requirements.

[0004] Due to the accumulation of machining errors of each part in the control mechanism, in order to better match the control mechanism with the product performance, the control mechanism needs to be adjusted multiple times during the product test process. In extreme cases, if the product performance requirements cannot be met, the control mechanism even needs to be replaced. Therefore, this kind of control mechanism adjusted along with the product is very difficult to match with other products. This leads to problems such as poor interchangeability of the control mechanism, long product debugging time, and low first-pass rate of products.

[0005] In addition, in actual work, the piston of the high-pressure oil cylinder in the control mechanism works in high-pressure oil, and its displacement cannot be directly measured, so the specific value of the displacement of the piston of the high-pressure oil cylinder in the control mechanism cannot be mastered. When a failure occurs, it is also impossible to conduct fault analysis by collecting the data of the displacement of the piston of the high-pressure oil cylinder in the control mechanism in the first time. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problems of being unable to directly measure the piston displacement of the high-pressure oil cylinder of the control mechanism, poor interchangeability of the control mechanism, long product debugging time, and low first-pass rate of products, and to provide a piston displacement measurement device and a piston detection method for a control mechanism of a double-variable piston pump.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A piston displacement measuring device for a control mechanism of a bidirectional variable piston pump, characterized in that it includes a bottom plate 11, a mounting plate 7 arranged on the bottom plate 11, a pin block 10, a positioning pin 8 for mounting and positioning the control mechanism 13, a positioning ring 9, an extended dial rod 2, a measuring gauge 4 and a gauge bracket 6;

[0009] The mounting plate 7 is provided with a high-pressure oil passage communicating with the oil circuit of the control mechanism, a positioning ring mounting hole 71, a pin block movement groove 72, and a positioning pin mounting hole;

[0010] The high-pressure oil passage is located at the upper end of the mounting plate 7, and high-pressure oil is introduced into the control mechanism 13 through a joint 1; the positioning pin mounting hole is located below the high-pressure oil passage and is used for mounting the positioning pin 8, and the control mechanism 13 is fixed on one side of the mounting plate 7 through the positioning pin 8;

[0011] The pin block movement groove 72 is arranged in the middle of the mounting plate 7, and the pin block 10 is installed in the pin block movement groove 72; one end of the pin block 10 is placed in the installation groove of the piston 14 and moves together with the piston 14; the other end passes through the mounting plate 7 and is connected to the measuring gauge 4 on the other side of the mounting plate 7;

[0012] The positioning ring mounting hole 71 is located at the center position of the pin block movement groove 72 and on the other side of the mounting plate 7; a through hole is opened in the center of the positioning ring 9, and an annular stop surface is provided on the outer side of one end. The positioning ring 9 is installed in the positioning ring mounting hole 71 through the other end of the pin block 10 during positioning testing, and the stop surface contacts the mounting plate 7;

[0013] A gap is left between the pin block 10 and the piston 14, between the through hole in the center of the pin block 10 and the positioning ring 9, and between the outer diameter of the positioning ring 9 and the positioning ring mounting hole 71;

[0014] The gauge bracket 6 is fixed at the lower end of the mounting plate 7, and a measuring gauge mounting hole is provided on the gauge bracket 6; one end of the extended dial rod 2 passes through the measuring gauge mounting hole and is threadedly connected to the dial rod of the measuring gauge 4, and the other end abuts against the surface of the pin block 10.

[0015] Further, the gap between the pin block 10 and the piston 14 is 0.02 - 0.04 mm.

[0016] Further, the gap between the through hole in the center of the pin block 10 and the positioning ring 9 is 0.02 - 0.04 mm.

[0017] Further, the gap between the outer diameter of the positioning ring 9 and the positioning ring mounting hole 71 on the mounting plate 7 is 0.02 - 0.04 mm.

[0018] Further, the pin block movement groove 72 is a waist-shaped hole, and its length is greater than the displacement of the piston 14.

[0019] The present invention also provides a method for detecting a piston of a control mechanism of a two-way variable plunger pump. Based on the above-mentioned displacement measuring device for the piston of the two-way variable plunger pump control mechanism, the special features are as follows: It includes the following steps:

[0020] Step 1: Install the control mechanism 13 on the mounting plate 7 through the positioning pin 8. At this time, the piston 14 is in the initial position; make the pin block 10 in the central position of the pin block movement groove 72, and adjust the reading of the measuring gauge 4 to the initial reading;

[0021] Step 2: Supply high-pressure oil to the control mechanism 13. Under the action of the high-pressure oil, the piston 14 starts to move to the other side from the initial position, driving the pin block 10 to move in the pin block movement groove 72, thereby driving the extension rod 2 so that the rod of the measuring gauge 4 extends or retracts with the movement of the pin block 10, and the reading of the measuring gauge 4 changes accordingly. The change amount is the displacement amount of the piston of the control mechanism;

[0022] Step 3: Determine whether the displacement amount of the piston of the control mechanism measured reaches the accuracy required by the product. If it does not reach the accuracy required by the product, adjust the adjusting nut on the control mechanism 13 to change the initial position of the piston 14, and return to Step 2 until the displacement amount of the piston 14 reaches the accuracy required by the product;

[0023] Step 4: Make the piston 14 move from a certain displacement amount to the initial position. The pointer of the measuring gauge 4 rotates in the opposite direction accordingly. When the piston 14 stops moving, the pointer of the measuring gauge 4 stops rotating at the same time. Record the reading of the measuring gauge 4. The difference from the initial reading is the centering value of the piston 14;

[0024] Step 5: Pass the positioning ring 9 through the pin block 10 and insert it into the positioning ring mounting hole 71 on the mounting plate 7 for positioning test. Judge whether the positioning ring 9 can be inserted and pulled out of the mounting plate 7 flexibly. If it can be inserted and pulled out flexibly and the centering value meets the specified requirements, then the centering accuracy of the piston 14 meets the usage requirements of the product; otherwise, adjust the adjusting nut on the control mechanism 13 to change the initial position of the piston 14, and repeat Steps 2 - 4 until both the displacement amount and the centering accuracy of the piston 14 meet the usage requirements of the product.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] 1. The displacement measuring device provided by the present invention connects the extension rod connected to the rod of the measuring gauge to the piston through the pin block, changing the displacement amount of the piston of the high-pressure oil cylinder of the invisible control mechanism into a highly visible visual value, with fast response and strong visibility, facilitating the debugging and fault analysis of the control mechanism;

[0027] 2. The displacement measuring device provided by the present invention can improve the measurement accuracy of the displacement of the piston of the high-pressure oil cylinder of the control mechanism by controlling the gap between the pin block and the piston;

[0028] 3. The piston detection method provided by the present invention measures the displacement accuracy and centering accuracy of the piston in the high-pressure oil cylinder of the control mechanism, adjusts the initial position of the piston of the control mechanism, and can independently debug the control mechanism before product assembly. The qualified control mechanism can be installed on any product of the same model, and can meet the matching requirements of the product without secondary debugging, with short debugging time, high first-pass rate and strong interchangeability of the product. Description of the Drawings

[0029] Figure 1 is a schematic view of the external structure of the high-pressure oil cylinder piston displacement measuring device provided by the present invention;

[0030] Figure 2 is a partial cross-sectional view of the high-pressure oil cylinder piston displacement measuring device provided by the present invention;

[0031] Figure 3 is a left view of the mounting plate of the high-pressure oil cylinder piston displacement measuring device provided by the present invention;

[0032] Figure 4 is a right view of the mounting plate of the high-pressure oil cylinder piston displacement measuring device provided by the present invention;

[0033] Figure 5 is a schematic view of the pin block structure of the high-pressure oil cylinder piston displacement measuring device provided by the present invention;

[0034] Figure 6 is Figure 5 right view of;

[0035] Description of the reference numerals is as follows:

[0036] 1 - joint, 2 - extended dial rod, 3 - screw, 4 - measuring gauge, 5 - screw, 6 - gauge bracket, 7 - mounting plate, 8 - positioning pin, 9 - positioning ring, 10 - pin block, 11 - bottom plate, 12 - screw, 13 - control mechanism, 14 - piston;

[0037] 71 - positioning ring mounting hole, 72 - pin block movement groove. Detailed Embodiments

[0038] To make the objectives, advantages and features of the present invention clearer, the following further describes in detail a two-way variable plunger pump control mechanism piston displacement measuring device and displacement detection method proposed by the present invention with reference to the drawings and specific embodiments. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention.

[0039] Such as Figure 1 、 Figure 2As shown in the figure, a piston displacement measuring device for a bidirectional variable piston pump control mechanism includes a bottom plate 11, a mounting plate 7 arranged on the bottom plate, a pin block 10, a positioning pin 8 for mounting and positioning the control mechanism, a positioning ring 9, an extended dial rod 2, a measuring gauge 4 and a gauge bracket 6. The mounting plate 7 is fixedly connected to the bottom plate 11 by screws. A high-pressure oil passage communicating with the oil circuit of the control mechanism is provided on the mounting plate 7. The high-pressure oil passage is located at the upper end of the mounting plate 7, and high-pressure oil is introduced into the control mechanism 13 through a joint 1.

[0040] As Figure 3 , Figure 4 shown in the figure, the mounting plate 7 is provided with a positioning ring mounting hole 71, a pin block movement groove 72, and a positioning pin mounting hole. The pin block movement groove 72 is a waist-shaped hole, and its length is greater than the displacement of the piston 14 of the control mechanism 13.

[0041] The positioning pin 8 is installed in the positioning pin mounting hole, and the control mechanism is fixed to one side of the mounting plate 7 through the positioning pin 8. The positioning ring mounting hole 71 is arranged on the other side of the mounting plate, at the central position of the pin block movement groove 72, and is used for installing the positioning ring 9. The pin block 10 is installed in the pin block movement groove 72, one end is placed in the installation groove of the piston 14 on the control mechanism 13, and moves together with the piston 14; the other end passes through the mounting plate 7 and is connected to the measuring gauge 4 on the other side of the mounting plate. Figure 5 , Figure 6 is the structural diagram of the pin block. A through hole is opened in the center of the positioning ring 9, and an annular stop surface is arranged on the outer side of one end. During positioning testing, it passes through the other end of the pin block 10 and is installed in the positioning ring mounting hole 71, and the stop surface contacts the mounting plate 7.

[0042] The gauge bracket 6 is used to fix the measuring gauge 4, and is provided with a measuring gauge mounting hole for installing the measuring gauge 4, and is fixed to the lower end of the mounting plate 7 by screws 12; the extended dial rod 2 is used to extend the dial rod of the measuring gauge 4 so that the measuring gauge 4 contacts the pin block 10; one end of the extended dial rod 2 is threadedly connected to the dial rod of the measuring gauge 4, and the other end is a plane, which abuts against the surface of the pin block 10. When the extended dial rod 2 abuts against the pin block 10, it is in a compressed state. When the pin block 10 drives the extended dial rod 2 to move to one side, the extended dial rod 2 continues to be compressed; when moving to the other side, the compressed part extends out. When the pin block 10 stops moving, it will block the further extension of the extended dial rod 2. The compression length of the extended dial rod 2 is determined by the piston stroke during design.

[0043] There are clearances between the pin block 10 and the piston 14, between the through holes at the centers of the pin block 10 and the positioning ring 9, and between the outer diameter of the positioning ring 9 and the positioning ring mounting hole 71 on the mounting plate 7. The clearance between the pin block 10 and the piston 14 is 0.02 - 0.04 mm, which is used to control the measurement accuracy of the displacement of the oil cylinder piston. The clearances between the through holes at the centers of the pin block 10 and the positioning ring 9, and between the outer diameter of the positioning ring 9 and the positioning ring mounting hole 71 on the mounting plate 7 are 0.02 - 0.04 mm respectively, which are used to accurately determine the centered state of the piston 14.

[0044] When the piston displacement measuring device of the bidirectional variable plunger pump control mechanism is in use, first install the joint 1, the mounting plate 7, and the bottom plate 11 together, then install the pin block 10 into the mounting groove on the piston 14 of the control mechanism 13, and then install them together onto the mounting plate 7, and then install the extension gauge rod 2, the measuring gauge 4, and the gauge holder 6.

[0045] The working principle of the piston displacement measuring device of the bidirectional variable plunger pump control mechanism provided by the present invention is as follows:

[0046] High-pressure oil is supplied to the control mechanism 13. The high-pressure oil enters one side of the high-pressure oil cylinder piston chamber of the control mechanism 13 through the high-pressure oil passage on the mounting plate 7. Under the action of the high-pressure oil, the piston 14 starts to move to one side from the initial position, driving the pin block 10 to move linearly in the pin block movement groove 72 on the mounting plate 7. Thus, the extension gauge rod 2 resting on the pin block 10 drives the gauge rod of the measuring gauge 4 to extend or retract along with the movement of the pin block 10, and the reading of the measuring gauge 4 is recorded. The difference from the initial reading is the displacement of the piston 14.

[0047] This embodiment also provides a method for detecting the piston of the bidirectional variable plunger pump control mechanism. Based on the above-mentioned high-pressure oil cylinder piston displacement measuring device, it includes the following steps:

[0048] Step 1: Install the control mechanism 13 onto the mounting plate 7 through the positioning pin 8. At this time, the piston 14 is in the initial position; make the pin block 10 in the central position of the pin block movement groove 72, and adjust the reading of the measuring gauge 4 to the initial reading.

[0049] Step 2: Supply high-pressure oil to the control mechanism 13. Under the action of the high-pressure oil, the piston 14 starts to move to the other side from the initial position, driving the pin block 10 to move in the pin block movement groove 72, thereby driving the extension gauge rod 2 to make the gauge rod of the measuring gauge 4 extend or retract along with the movement of the pin block 10. The reading of the measuring gauge 4 changes accordingly, and the change amount is the displacement of the control mechanism piston.

[0050] Step 3: Determine whether the displacement of the control mechanism piston measured reaches the accuracy required by the product. If it does not reach the accuracy required by the product, adjust the adjusting nut on the control mechanism 13 to change the initial position of the piston 14, and return to Step 2 until the displacement of the piston 14 reaches the accuracy required by the product;

[0051] Step 4: Move the piston 14 from a certain displacement to the initial position. Measure that the pointer of the measuring gauge 4 rotates in the opposite direction accordingly. When the piston 14 stops moving, the pointer of the measuring gauge 4 stops rotating simultaneously. Record the reading of the measuring gauge 4, and the difference from the initial reading is the centering value of the piston 14;

[0052] Step 5: Pass the positioning ring 9 through the pin block 10 and insert it into the positioning ring mounting hole 71 on the mounting plate 7 for positioning test. Determine whether the positioning ring 9 can be inserted into and pulled out of the mounting plate 7 flexibly. If it can be inserted into and pulled out flexibly and the centering value meets the specified requirements, then the centering accuracy of the piston 14 meets the usage requirements of the product; otherwise, adjust the adjusting nut on the control mechanism 13 to change the initial position of the piston 14, and repeat Step 2 to Step 4 until both the displacement and centering accuracy of the piston 14 meet the usage requirements of the product.

[0053] In Step 3, determine whether the displacement of the control mechanism piston measured reaches the accuracy required by the product. Since the part dimensions of the control mechanism 13 determine the basic dimension of the displacement, the measurement accuracy of the displacement can be obtained by simply comparing the measured displacement with the displacement determined by the control mechanism 13.

[0054] In this method, if the measured displacement accuracy does not reach the accuracy required by the product and the centering accuracy of the piston 14 does not meet the usage requirements of the product, the adjusting nut on the control mechanism 13 needs to be adjusted. After adjusting the adjusting nut on the control mechanism 13 due to either the displacement accuracy or the centering accuracy not meeting the requirements, the other one needs to be re-tested.

Claims

1. A method for detecting a piston of a control mechanism of a dual-variable piston pump, which uses a piston displacement measuring device. The piston displacement measuring device includes a bottom plate (11), a mounting plate (7) arranged on the bottom plate (11), a pin block (10), a positioning pin (8) for mounting and positioning the control mechanism (13), a positioning ring (9), an extended dial rod (2), a measuring dial (4) and a dial frame (6); The mounting plate (7) is provided with a high-pressure oil passage communicating with the oil circuit of the control mechanism, a positioning ring mounting hole (71), a pin block movement groove (72), and a positioning pin mounting hole; The high-pressure oil passage is located at the upper end of the mounting plate (7), and high-pressure oil is introduced into the control mechanism (13) through a joint (1); the positioning pin mounting hole is located below the high-pressure oil passage and is used for mounting the positioning pin (8), and the control mechanism (13) is fixed on one side of the mounting plate (7) through the positioning pin (8); The pin block movement groove (72) is arranged in the middle of the mounting plate (7), and the pin block (10) is installed in the pin block movement groove (72); one end of the pin block (10) is placed in the installation groove of the piston (14) and moves together with the piston (14); the other end passes through the mounting plate (7) and is connected to the measuring dial (4) on the other side of the mounting plate (7); The positioning ring mounting hole (71) is located at the central position of the pin block movement groove (72) and on the other side of the mounting plate (7); a through hole is opened in the center of the positioning ring (9), and an annular abutting surface is arranged on the outer side of one end. The positioning ring (9) is installed in the positioning ring mounting hole (71) through the other end of the pin block (10) during positioning testing, and the abutting surface contacts the mounting plate (7); There are gaps between the pin block (10) and the piston (14), the through holes in the centers of the pin block (10) and the positioning ring (9), and the outer diameter of the positioning ring (9) and the positioning ring mounting hole (71); The dial frame (6) is fixed at the lower end of the mounting plate (7), and a measuring dial mounting hole is arranged on the dial frame (6); one end of the extended dial rod (2) passes through the measuring dial mounting hole and is threadedly connected to the dial rod of the measuring dial (4), and the other end abuts against the pin block (10); It is characterized in that It includes the following steps: Step 1: Install the control mechanism (13) onto the mounting plate (7) through the positioning pin (8). At this time, the piston (14) is in the initial position. Place the pin block (10) at the center position of the pin block movement groove (72), and adjust the reading of the measuring gauge (4) to the initial reading. Step 2: Supply high-pressure oil to the control mechanism (13). Under the action of the high-pressure oil, the piston (14) moves from the initial position to one side, driving the pin block (10) to move within the pin block movement groove (72), thereby driving the extension gauge rod (2) to cause the gauge rod of the measuring gauge (4) to extend or retract along with the movement of the pin block (10). The reading of the measuring gauge (4) changes accordingly, and the change amount is the displacement of the piston of the control mechanism. Step 3: Determine whether the displacement of the piston of the control mechanism measured reaches the accuracy required by the product. If it does not reach the accuracy required by the product, adjust the adjusting nut on the control mechanism (13) to change the initial position of the piston (14), and return to Step 2 until the displacement of the piston (14) reaches the accuracy required by the product. Step 4: Move the piston (14) from a certain displacement to the initial position. The pointer of the measuring gauge (4) rotates in the opposite direction accordingly. When the piston (14) stops moving, the pointer of the measuring gauge (4) stops rotating simultaneously. Record the reading of the measuring gauge (4), and the difference from the initial reading is the centering value of the piston (14). Step 5: Pass the positioning ring (9) through the pin block (10) and insert it into the positioning ring mounting hole (71) on the mounting plate (7) for positioning test. Determine whether the positioning ring (9) can be inserted into and pulled out of the mounting plate (7) flexibly. If it can be inserted and pulled out flexibly and the centering value meets the specified requirements, then the centering accuracy of the piston (14) meets the usage requirements of the product; otherwise, adjust the adjusting nut on the control mechanism (13) to change the initial position of the piston (14), and repeat Steps 2 - 4 until both the displacement and centering accuracy of the piston (14) meet the usage requirements of the product.

2. The method for detecting a piston of a control mechanism of a dual-variable piston pump according to claim 1, characterized in that: The clearance between the pin block (10) and the piston (14) is 0.02 - 0.04 mm.

3. The piston detection method of the dual-variable piston pump control mechanism according to claim 2, characterized in that: The clearance between the through hole at the center of the pin block (10) and the positioning ring (9) is 0.02 - 0.04 mm.

4. The piston detection method of the dual-variable piston pump control mechanism according to claim 3, characterized in that: The clearance between the outer diameter of the positioning ring (9) and the positioning ring mounting hole (71) on the mounting plate (7) is 0.02 - 0.04 mm.

5. The piston detection method of the dual-variable piston pump control mechanism according to claim 4, characterized in that: The pin block movement groove (72) is an oval hole, and its length is greater than the displacement of the piston (14).

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