Backpressure system of extrusion grinding machine

Abstract

According to the backpressure system of the extrusion grinding machine, the extrusion grinding machine comprises a front-end tool and a rear-end tool which are used for clamping a workpiece, a micropore for clamping the workpiece is communicated with a feeding port of the front-end tool and a discharging port of the rear-end tool, and the feeding port of the front-end tool is communicated with an abrasive particle flow input mechanism; the material outlet is respectively communicated with a grinding material box and a back pressure device which are positioned below the material outlet through pipelines, the back pressure device comprises a back pressure cylinder, the pipelines are connected with a back pressure reversing valve, the back pressure reversing valve comprises a first outlet and a second outlet, the first outlet is communicated with the grinding material box, and the second outlet is communicated with the back pressure cylinder; and an outlet of the backpressure cylinder is communicated with the grinding material box through a backpressure discharging valve. Backpressure generated by the backpressure cylinder and abrasive particle flow entering the backpressure cylinder form reverse pressure until the backpressure is adjusted to preset pressure, outlet pressure of the micropores cannot be suddenly reduced to normal pressure from high pressure at the front ends of the micropores, scattering of the abrasive particle flow in the uncontrollable direction at the outlets of the micropores is reduced, and the abrasion resistance of the micropores is improved. And the phenomenon that the roundness of a micropore outlet is damaged is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of extrusion grinders, in particular to a back pressure system for an extrusion grinder. Background Art

[0002] The aperture of the micropores of the electric valve plate or the fuel injector is relatively small, generally 0.15-0.3㎜. Such micropores are generally drilled by electric sparks. After electric spark drilling, burrs will remain at the opening. The burrs will affect the flow of the electric valve plate or the fuel injector, and thus affect its spray effect. Generally, the micropores need to be ground by an extrusion grinder. The function of the extrusion grinder is to remove burrs and polish the inner wall of the micropores by passing high-pressure abrasives (abrasive flow) through the micropores. The extrusion grinder includes a workbench and a front-end tooling and a rear-end tooling arranged thereon. The front-end tooling and the rear-end tooling are used together to clamp the electric valve plate or the fuel injector. The high-pressure abrasive passes from the front-end tooling through the electric valve plate to the rear-end tooling, and is discharged from the pre-opened outlet of the rear-end tooling.

[0003] For the micropore extrusion of single-hole valve plates or control valves of some high-pressure common rail injectors, although controllable extrusion grinding under real-time online flow monitoring has been achieved, the roundness of the micropores after extrusion and grinding is not ideal when observed under a microscope. Some micropores are extruded into ellipses, and some micropores are even squeezed out with notches. This is because the outlet end of the micropore is directly connected to an open pipeline back to the fuel tank, causing the outlet pressure of the micropore to suddenly drop from the high pressure at the front end (usually 60-100 bar) to normal pressure. The abrasive (abrasive flow) is scattered in an uncontrollable direction at the outlet, and the cutting force of the abrasive destroys the roundness of the micropore outlet, causing the micropore roundness to be destroyed. Although the flow rate meets the requirements, the product quality does not meet the requirements and cannot be used. Utility Model Content

[0004] In order to solve the technical problems existing in the above background technology, the utility model provides a back pressure system for an extrusion grinder.

[0005] The technical solution of this utility model is as follows:

[0006] A back pressure system for an extrusion grinder, comprising a front end tooling and a rear end tooling for clamping a workpiece, wherein a micropore for clamping the workpiece is connected to a feed port of the front end tooling and a discharge port of the rear end tooling, wherein the feed port of the front end tooling is connected to an abrasive flow input mechanism, and the discharge port of the rear end tooling is connected to an abrasive box and a back pressure device located below the front end tooling via a pipeline, respectively. The back pressure device comprises a back pressure cylinder, and a back pressure reversing valve is connected to the pipeline. The back pressure reversing valve comprises a first outlet and a second outlet, wherein the first outlet is connected to the abrasive box, and the second outlet is connected to the inlet of the back pressure cylinder, and the outlet of the back pressure cylinder is connected to the abrasive box via a back pressure discharge valve.

[0007] The backpressure system has at least three states:

[0008] In the grinding state, the second outlet can be opened when the abrasive flow input mechanism is in the open state, and the first outlet and the back pressure discharge valve are closed;

[0009] In the pressure maintaining state, in the grinding state, the first outlet is opened and the second outlet is closed;

[0010] In the adjustment state, the first outlet can be opened when the abrasive flow input mechanism is in the closed state, the second outlet is closed, and the back pressure discharge valve is opened.

[0011] When the first outlet and the back-pressure discharge valve are closed, the abrasive flow input mechanism applies a stable pressure to the micropores of the workpiece to be ground, and the abrasive flow therein passes through the micropores of the workpiece and enters the back-pressure cylinder. The back-pressure cylinder is started to adjust the pressure of the hydraulic oil, so that the back-pressure pressure generated by the back-pressure cylinder and the abrasive flow entering the back-pressure cylinder form a reverse pressure until the back-pressure pressure is adjusted to the preset pressure, thereby realizing closed-loop control of the back-pressure pressure, preventing the outlet pressure of the micropore from suddenly dropping from the high pressure at its front end to normal pressure, reducing the scattering of the abrasive flow in uncontrollable directions at the outlet of the micropore, and reducing the phenomenon of damage to the outlet roundness of the micropore.

[0012] The structure of the back pressure device is that the back pressure device also includes a hydraulic pump and a pressure regulating valve respectively connected to the back pressure cylinder, and the hydraulic pump and the pressure regulating valve are arranged on the side of the back pressure cylinder away from the workpiece.

[0013] The installation position of the abrasive box and the back pressure device is that a support frame is provided below the extrusion grinder, and the abrasive box and the back pressure device are arranged in the support frame.

[0014] The abrasive flow is a recyclable abrasive. In order to facilitate the abrasive flow to enter the abrasive box and then return to the abrasive flow input mechanism for recycling, the abrasive box is connected to the inlet of the abrasive flow input mechanism through an external reflux mechanism.

[0015] The burrs of the micropores of the workpiece and the grinding chips generated by the abrasive flow will remain in the abrasive flow. The abrasive flow of the utility model is oily abrasive. In order to facilitate the filtering of larger particles of burrs and increase the number of times the abrasive flow is used, the first outlet is connected to the abrasive box through a first pipe. A filter assembly is provided on the inner side of the upper part of the abrasive box. The filter assembly includes a filter screen. The outlet of the first pipe is located above the filter screen, and the larger particles of burrs in the abrasive flow are filtered through the filter screen.

[0016] There is a lot of abrasive flow remaining in the back pressure cylinder. In order to filter the burrs in the abrasive flow, the outlet of the back pressure discharge valve is connected to the filter assembly through a second pipe.

[0017] The specific structure of the above-mentioned filter screen is that the filter screen is a cylindrical filter cartridge, the bottom of the filter cartridge is detachably connected to a bottom cover, the filter cartridge is inserted into the cover plate on the upper part of the abrasive box, and its bottom is lower than the lower surface of the cover plate. The outlets of the first pipe and the second pipe are located inside the filter cartridge.

[0018] In order to facilitate the cleaning of grinding chips and burrs in the abrasive flow, a magnetic attraction piece is provided on the inner bottom surface of the filter cartridge.

[0019] The beneficial effects of the present invention are:

[0020] The workpiece to be polished with micro-holes is pressed by the front-end tooling and the rear-end tooling, the first outlet and the back-pressure discharge valve are closed, and the abrasive flow input mechanism is started to apply a stable pressure of 100 bar to the micro-holes of the workpiece, so that the abrasive flow therein passes through the micro-holes of the workpiece and polishes the inlet, outlet and inner wall of the micro-hole. The abrasive flow from the outlet of the micro-hole passes through the back-pressure reversing valve and enters the back-pressure cylinder. The back-pressure cylinder is started to adjust the pressure of the pressure oil of the hydraulic pump so that the back-pressure pressure generated by the back-pressure cylinder forms a reverse pressure with the abrasive flow entering the back-pressure cylinder until the back-pressure pressure is adjusted to the preset pressure. The preset pressure can generally be set to 40 bar to realize closed-loop control of the back-pressure pressure. Continuous extrusion and polishing in this state will not cause the outlet pressure of the micro-hole to suddenly drop from the high pressure at its front end to normal pressure, thereby reducing the scattering of the abrasive flow in uncontrollable directions at the outlet of the micro-hole and reducing the phenomenon of damage to the roundness of the outlet of the micro-hole.

[0021] After the flow rate of the abrasive flow reaches the preset value, the abrasive flow input mechanism is closed, and no more abrasive flow is input to the micropores. The second outlet is closed, and the first outlet is opened to discharge the abrasive flow in the pipeline into the abrasive box, so that there is still an abrasive flow with a pressure of 40 bar in the back pressure cylinder. When waiting for the next extrusion cycle, the back pressure can quickly reach the preset value of 40 bar.

[0022] In order to maintain the stability of the back pressure system and the number of times the abrasive flow is used, a filter assembly is provided on the abrasive box. The filter assembly can filter the abrasive flow discharged from the first pipe and the second pipe, so that the grinding chips and burrs in the abrasive flow can be intercepted by the filter mesh;

[0023] Moreover, the grinding chips and burrs can be magnetically attracted to the magnetic attraction part, which is convenient for absorbing smaller grinding chips and collecting the grinding chips and burrs, and preventing them from being washed into the abrasive box by the abrasive flow through the filter screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In the attached figure:

[0025] Figure 1 It is a structural diagram;

[0026] Figure 2 This is the schematic diagram of the back pressure system;

[0027] Figure 3 for Figure 1 A in the middle is an enlarged structural diagram;

[0028] The components represented by the reference numerals in the figure are:

[0029] 1. Front-end tooling; 2. Rear-end tooling; 3. Workpiece; 4. Abrasive box; 41. Cover plate; 5. Back-pressure cylinder; 6. Hydraulic pump; 7. Pressure regulating valve; 8. Support frame; 9. Back-pressure reversing valve; 91. First outlet; 92. Second outlet; 10. Back-pressure unloading valve; 11. First pipeline; 12. Second pipeline; 13. Filter cartridge; 14. Bottom cover; 15. Top cover; 16. Magnetic element; 17. Reflux mechanism. DETAILED DESCRIPTION

[0030] See also Figure 1 and Figure 2 As shown, a back pressure system for an extrusion grinder is provided. The extrusion grinder includes a front fixture 1 and a rear fixture 2 for clamping a workpiece 3. The micropores for clamping the workpiece 3 are connected to the feed port of the front fixture 1 and the discharge port of the rear fixture 2. The feed port of the front fixture 1 is connected to an abrasive flow input mechanism. The above is prior art and will not be described in detail. In this embodiment, the discharge port of the rear fixture 2 is connected to an abrasive box 4 and a back pressure device located below it through pipes. A support frame 8 is provided below the extrusion grinder, and the abrasive box 4 and the back pressure device are arranged within the support frame 8. A hydraulic pump 6 and a pressure regulating valve 7 are arranged on the side of the back pressure cylinder 5 away from the workpiece 3.

[0031] The back pressure device includes a back pressure cylinder 5, a hydraulic pump 6 and a pressure regulating valve 7 respectively connected to the back pressure cylinder 5, and a back pressure reversing valve 9 is connected to the pipeline. The back pressure reversing valve 9 is a three-way reversing valve. The back pressure reversing valve 9 includes an inlet, a first outlet 91 and a second outlet 92. The first outlet 91 is connected to the abrasive box 4, and the second outlet 92 is connected to the inlet of the back pressure cylinder 5. The outlet of the back pressure cylinder 5 is connected to the abrasive box 4 through the back pressure unloading valve 10.

[0032] The backpressure system has at least three states:

[0033] In the grinding state, the second outlet 92 can be opened when the abrasive flow input mechanism is in the open state, and the first outlet 91 and the back pressure discharge valve 10 are closed;

[0034] In the pressure maintaining state, in the grinding state, the first outlet 91 is opened and the second outlet 92 is closed;

[0035] In the adjustment state, the first outlet 91 can be opened when the abrasive flow input mechanism is in the closed state, the second outlet 92 is closed, and the back pressure discharge valve 10 is opened.

[0036] When the first outlet 91 and the back-pressure discharge valve 10 are closed, the abrasive flow input mechanism applies a stable pressure to the micropores of the workpiece 3 to be ground, and the abrasive flow therein passes through the micropores of the workpiece 3 and enters the back-pressure cylinder 5. The back-pressure cylinder 5 is started to adjust the pressure of the hydraulic oil, so that the back-pressure pressure generated by the back-pressure cylinder 5 forms a reverse pressure with the abrasive flow entering the back-pressure cylinder 5 until the back-pressure pressure is adjusted to the preset pressure, thereby realizing closed-loop control of the back-pressure pressure, preventing the outlet pressure of the micropore from suddenly dropping from the high pressure at its front end to normal pressure, reducing the scattering of the abrasive flow in an uncontrollable direction at the outlet of the micropore, and reducing the phenomenon of damage to the outlet roundness of the micropore.

[0037] The abrasive flow is a recyclable abrasive. In order to facilitate the abrasive flow to enter the abrasive box 4 and return to the abrasive flow input mechanism for recycling, the abrasive box 4 is connected to the inlet of the abrasive flow input mechanism through an external reflux mechanism 17.

[0038] In the grinding state, the workpiece 3 being squeezed and ground, such as the electric valve plate or the oil nozzle, has a stable pressure of 100br applied to the front end of the micropore. The abrasive flows through the micropore. At this time, the back pressure discharge valve 10 is closed, the back pressure reversing valve 9 is energized, the second outlet 92 is connected, the first outlet 91 is closed, and the abrasive flows into the back pressure cylinder 5. The hydraulic pump 6 starts to send hydraulic oil into the back pressure cylinder 5. The system controls the pressure regulating valve 7 to adjust the pressure of the hydraulic oil and presses the piston of the back pressure cylinder 5 downward, forming a force in the opposite direction to the abrasive entering the back pressure cylinder 5. The back pressure sensor of the extrusion grinder monitors the back pressure value in real time and feeds back to the control system to adjust the current of the pressure regulating valve 7 until the back pressure is equal to the set pressure of 40bar, thereby realizing closed-loop control of the back pressure and realizing continuous extrusion of the micropore at the front end pressure of 100bar and the back pressure of 40bar.

[0039] In the pressure-maintaining state, when the flow rate of the abrasive flow reaches the preset value, the front-end pressure of the micropore is canceled, that is, the abrasive flow input mechanism is closed, the abrasive flow no longer passes through the micropore of the workpiece 3, the back-pressure reversing valve 9 loses power, the second outlet 92 is closed, and the first outlet 91 is connected, so that the abrasive in the pipeline is discharged to the abrasive box 4, releasing the pressure in the pipeline; the back-pressure discharge valve 10 is still in the closed state, and the abrasive flow with a pressure of 40 bar is maintained in the back-pressure cylinder 5. When waiting for the next extrusion cycle, the back pressure can quickly reach the preset value of 40 bar, avoiding repeated adjustment of the back pressure;

[0040] The back-pressure cylinder 5 includes an upper limit sensor and a lower limit sensor, which is a prior art. In the regulated state, during the extrusion process, when the piston rod of the back-pressure cylinder 5 rises to the upper limit sensor position, the front-end pressure of the micropore is removed, the abrasive flow no longer passes through the micropore, the back-pressure reversing valve 9 loses power, the second outlet 92 closes, and the first outlet 91 opens, discharging the abrasive flow in the pipeline into the abrasive box 4, releasing the pressure in the pipeline. The back-pressure discharge valve 10 is energized and opened. Under the pressure provided by the hydraulic pump 6, the back-pressure cylinder 5 presses the abrasive back into the abrasive box 4 until the piston of the back-pressure cylinder 5 reaches the lower limit sensor position, closing the back-pressure discharge valve 10 and waiting for the next extrusion cycle.

[0041] The burrs and grinding debris generated by the abrasive flow grinding the micropores of the workpiece 3 will remain in the abrasive flow. The abrasive flow of the utility model is oily abrasive. In order to facilitate the filtering of larger burrs and increase the number of times the abrasive flow is used, the first outlet 91 is connected to the abrasive box 4 through the first pipe 11. The abrasive box 4 is provided with a filter assembly on the inner side of the upper part. The filter assembly includes a filter screen. The outlet of the first pipe 11 is located above the filter screen, and the filter screen is used to filter the larger burrs in the abrasive flow. There is a lot of abrasive flow remaining in the back pressure cylinder 5. In order to filter the burrs in the abrasive flow therein, the outlet of the back pressure discharge valve 10 is connected to the filter assembly through the second pipe 12.

[0042] See also Figure 1 and Figure 3 As shown, the specific structure of the above-mentioned filter screen is that the filter screen is a cylindrical filter cartridge 13, and a top cover 15 is provided at the upper end of the filter cartridge 13. The top cover 15 is provided with a socket adapted to the first pipe 11 and the second pipe 12. The bottom of the filter cartridge 13 is detachably connected to the bottom cover 14. The filter cartridge 13 is inserted into the cover plate 41 on the upper part of the abrasive box 4, and its bottom is lower than the lower surface of the cover plate 41. The outlets of the first pipe 11 and the second pipe 12 are located inside the filter cartridge 13.

[0043] To facilitate the removal of grinding debris and burrs from the abrasive flow, a magnetic element 16 is provided on the upper surface of the bottom cover 14. The bottom cover 14 is threadedly connected to the filter cartridge 13, making it easy to remove the bottom cover 14 and clean the grinding debris and burrs from the magnetic element 16. The grinding debris and burrs are magnetically attracted to the magnetic element 16, facilitating the absorption of smaller grinding debris and burrs, thereby facilitating their collection and preventing them from being washed into the abrasive box 4 by the abrasive flow through the filter screen.

Claims

1. A back pressure system for an extrusion grinder, comprising a front end tooling (1) and a rear end tooling (2) for clamping a workpiece (3), wherein a micropore for clamping the workpiece (3) is connected to a feed port of the front end tooling (1) and a discharge port of the rear end tooling (2), and the feed port of the front end tooling (1) is connected to an abrasive flow input mechanism, characterized in that: The discharge port of the rear end tooling (2) is connected to the abrasive box (4) and the back pressure device located below it through pipelines; The back pressure device comprises a back pressure cylinder (5), a back pressure reversing valve (9) is connected to the pipeline, the back pressure reversing valve (9) comprises a first outlet (91) and a second outlet (92), the first outlet (91) is communicated with the abrasive box (4), the second outlet (92) is communicated with the inlet of the back pressure cylinder (5), the outlet of the back pressure cylinder (5) is communicated with the abrasive box (4) via a back pressure discharge valve (10), and the first outlet (91) and the second outlet (92) are not opened at the same time.

2. The back pressure system of an extrusion grinding machine according to claim 1, characterized in that: The back pressure device further comprises a hydraulic pump (6) and a pressure regulating valve (7) respectively connected to the back pressure cylinder (5); the hydraulic pump (6) and the pressure regulating valve (7) are arranged on a side of the back pressure cylinder (5) away from the workpiece (3).

3. The back pressure system of an extrusion grinding machine according to claim 1, characterized in that: A support frame (8) is provided below the extrusion grinder, and the abrasive box (4) and the back pressure device are arranged inside the support frame (8).

4. The back pressure system of an extrusion grinding machine according to claim 1, characterized in that: The abrasive box (4) is connected to the inlet of the abrasive flow input mechanism through an external reflux mechanism (17).

5. The back pressure system of an extrusion grinding machine according to claim 1, characterized in that: The first outlet (91) is connected to the abrasive box (4) through a first pipe (11). A filter assembly is provided on the inner side of the upper portion of the abrasive box (4). The filter assembly includes a filter screen. The outlet of the first pipe (11) is located above the filter screen.

6. The back pressure system of an extrusion grinding machine according to claim 5, characterized in that: The outlet of the back pressure discharge valve (10) is connected to the filter assembly via a second pipeline (12).

7. The back pressure system of an extrusion grinding machine according to claim 6, characterized in that: The filter screen is a cylindrical filter cartridge (13), the bottom of the filter cartridge (13) is detachably connected to a bottom cover (14), the filter cartridge (13) is inserted into a cover plate (41) on the upper part of the abrasive box (4), the bottom of the filter cartridge (13) is lower than the lower surface of the cover plate (41), and the outlets of the first pipe (11) and the second pipe (12) are located inside the filter cartridge (13).

8. The back pressure system of an extrusion grinding machine according to claim 7, characterized in that: A magnetic attraction member (16) is provided on the inner bottom surface of the filter cylinder (13).

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