A mechanical high cycle gas pressure fatigue testing machine

Abstract

The present invention discloses a mechanical high-cycle gas pressure fatigue testing machine, including a cylindrical rotary valve, an outer sleeve, a high-pressure ventilation chamber, a pressure chamber, a low-pressure ventilation chamber, a sealing end cover, a cross coupling, and a servo motor; the cylindrical rotary valve is installed in the outer sleeve, and a sealing end cover is arranged on the inner side of the end of the cylindrical rotary valve, and the outer side of the end of the cylindrical rotary valve is connected to the servo motor through a cross coupling; the high-pressure ventilation chamber, the pressure chamber and the low-pressure ventilation chamber are arranged in sequence on the cylindrical rotary valve, and the tested object is arranged in the pressure chamber, and the high-pressure ventilation chamber and the low-pressure ventilation chamber are respectively provided with two air inlets for connecting the high-pressure gas source and the low-pressure gas source, and the cylindrical rotary valve is provided with ventilation holes at the high-pressure ventilation chamber and the low-pressure ventilation chamber, and the high-pressure ventilation chamber and the low-pressure ventilation chamber are alternately connected to the pressure chamber through the rotation of the cylindrical rotary valve, so as to apply a periodically changing dynamic pressure to the tested object. The present invention can be applied under high-pressure conditions and meet the requirements of high cycle life and high stability.

Description

Technical Field

[0001] The invention belongs to the field of test technology and relates to a gas pressure fatigue testing machine, in particular to a mechanical high-cycle gas pressure fatigue testing machine. Background Art

[0002] The gas pressure fatigue testing machine can provide gas pulsating pressure with adjustable frequency and amplitude for more than 1,000,000 cycles to the tested object, observe the deformation of the tested object under this condition, or measure the change of the output of the tested object, and finally obtain the characteristics and fatigue life parameters of the tested object under alternating cyclic pressure. Fatigue life test is required for various types of sensors. The sensor is installed on the pressure alternating load testing machine, and the sensor is subjected to the specified sinusoidal or trapezoidal wave alternating pressure test, and then pressure calibration is performed. With the development of industrial level, the application scope of pressure sensors is becoming more and more extensive, and the demand for pressure fatigue life detection is also increasing accordingly.

[0003] At present, the main technical difficulty of gas pressure fatigue testing machine is to meet the requirements of high cycle number and high reliability at the same time. Therefore, the structure of each component should be as simple and effective as possible during the design process. In the structural and system design of gas pressure fatigue testing machine, the cycle life and working stability of each component are mainly considered. Therefore, the commonly used solenoid valve square wave signal generator needs to replace key components frequently due to the limitation of the life of the solenoid valve and control circuit. In order to meet the requirements of gas pressure fatigue testing such as sensors, the test device needs to be easy and stable to operate, and the device itself needs to have a sufficient cycle life. Summary of the invention

[0004] The purpose of the present invention is to provide a mechanical high cycle gas pressure fatigue testing machine which can be applied under high pressure conditions and meet the requirements of high cycle life and high stability.

[0005] One aspect of the present invention provides a mechanical high cycle gas pressure fatigue testing machine, comprising a cylindrical rotary valve, an outer sleeve, a high pressure ventilation chamber, a pressure chamber, a low pressure ventilation chamber, a sealing end cover, a cross coupling, and a servo motor;

[0006] The cylindrical rotary valve is installed in the outer sleeve and can rotate in the outer sleeve. A sealing end cap is provided on the inner side of the end of the cylindrical rotary valve. The outer side of the end of the cylindrical rotary valve is connected to the servo motor through the cross coupling. The servo motor is used to drive the cylindrical rotary valve to rotate.

[0007] A high-pressure ventilation chamber, a pressure chamber and a low-pressure ventilation chamber are arranged in sequence on the cylindrical rotary valve, and the test piece is arranged in the pressure chamber. The high-pressure ventilation chamber and the low-pressure ventilation chamber are respectively provided with two air inlets for connecting the high-pressure gas source and the low-pressure gas source. The cylindrical rotary valve is provided with ventilation holes at the high-pressure ventilation chamber and the low-pressure ventilation chamber. Through the rotation of the cylindrical rotary valve, the high-pressure ventilation chamber and the low-pressure ventilation chamber are alternately connected to the corresponding high-pressure gas source and the low-pressure gas source, and the pressure chamber is alternately connected, thereby applying a periodically changing dynamic pressure to the test piece.

[0008] Preferably, the ventilation holes at the high-pressure ventilation chamber and the low-pressure ventilation chamber are opened at an angle of 45°.

[0009] Preferably, the interiors of the high-pressure ventilation chamber and the low-pressure ventilation chamber are cross-shaped air paths that intersect vertically and have the same inner diameter, and the outer sleeve has air holes at the high-pressure ventilation chamber and the low-pressure ventilation chamber, and the diameter of the air holes is the same as the inner diameter of the high-pressure ventilation chamber and the low-pressure ventilation chamber.

[0010] Preferably, the pressure chamber has eight air holes evenly distributed along the circumferential direction, four of which are in the same direction as the high-pressure ventilation chamber, and the other four are in the same direction as the low-pressure ventilation chamber. The outer sleeve has air holes at the pressure chamber, and the diameter of the air holes is twice that of the air holes inside the pressure chamber.

[0011] Preferably, the openings of the high-pressure ventilation chamber and the low-pressure ventilation chamber satisfy a ratio of 1:3 between the circumference of the outer diameter of the cylindrical rotary valve occupied by the openings and the circumference occupied by the non-openings.

[0012] Preferably, a sealing structure is provided between the pressure chamber and the high-pressure ventilation chamber and the low-pressure ventilation chamber for sealing between the pressure chamber and the high-pressure ventilation chamber and the low-pressure ventilation chamber.

[0013] Preferably, the sealing structure is a composite sealing system consisting of three O-rings and a polytetrafluoroethylene filling material.

[0014] Preferably, the outer sleeve is connected to the inner cylindrical rotary valve via a high-precision bearing.

[0015] Preferably, it also includes a pressure reducing valve, and the high-pressure gas source is connected to the high-pressure ventilation chamber through the pressure reducing valve.

[0016] The mechanical high cycle gas pressure fatigue testing machine of the above aspect of the present invention can be applied to high pressure conditions and meet the requirements of high cycle life and high stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0018] Figure 1 It is a schematic diagram of the principle of a mechanical high cycle gas pressure fatigue testing machine according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of the main structure of an embodiment of the present invention;

[0020] The reference numerals are:

[0021] 1- cylindrical rotary valve, 2- outer sleeve, 3- high-pressure ventilation chamber, 4- pressure chamber, 5- low-pressure ventilation chamber, 6- sealing end cover, 7- cross coupling, 8- servo motor, 9- pressure reducing valve. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] An embodiment of the present invention provides a mechanical high cycle gas pressure fatigue testing machine, Figure 1 FIG. 1 is a schematic diagram of the principle of a mechanical high cycle gas pressure fatigue testing machine according to an embodiment of the present invention. Figure 1 As shown, the mechanical high cycle gas pressure fatigue testing machine of the embodiment of the present invention includes: a cylindrical rotary valve 1, an outer sleeve 2, a high pressure ventilation chamber 3, a pressure chamber 4, a low pressure ventilation chamber 5, a sealing end cover 6, a cross coupling 7, a servo motor 8, and a pressure reducing valve 9.

[0024] Among them, the cylindrical rotary valve 1, the outer sleeve 2, the high-pressure ventilation chamber 3, the pressure chamber 4, the low-pressure ventilation chamber 5 and the sealing end cover 6 constitute a rotary valve type dynamic pressure generator, which is the main structure of the mechanical high-cycle gas pressure fatigue testing machine of an embodiment of the present invention. Figure 2 It is a schematic diagram of the main structure of an embodiment of the present invention.

[0025] like Figure 1 and Figure 2As shown, the cylindrical rotary valve 1 is installed inside the outer sleeve 2, and the outer sleeve 2 is connected to the cylindrical rotary valve 1 inside through a high-precision bearing to ensure that the cylindrical rotary valve 1 can rotate stably inside the outer sleeve 2. The cylindrical rotary valve 1 and the outer sleeve 2 are processed in coordination to ensure smooth installation and good sealing.

[0026] The end of the cylindrical rotary valve 1 is provided with a sealing end cap 6, which is connected to the inner side of the cylindrical rotary valve 1 through a thread to seal the gas path. The outer side of the end of the cylindrical rotary valve 1 is provided with a keyway structure, which is connected to the servo motor 8 through a cross coupling 7. The pressure distribution inside the pressure chamber 4 can be changed by controlling the speed and rotation mode of the servo motor 8.

[0027] The high-pressure ventilation chamber 3, the pressure chamber 4 and the low-pressure ventilation chamber 5 are arranged in sequence on the cylindrical rotary valve 1, and there are through holes inside, which are connected through the internal gas path of the cylindrical rotary valve 1. The cylindrical rotary valve 1 is divided into three parts: the high-pressure ventilation chamber 3, the pressure chamber 4 and the low-pressure ventilation chamber 5 through a composite sealing system composed of three "0" rings and polytetrafluoroethylene filling materials.

[0028] The high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 are respectively provided with two air inlets for connecting the high-pressure gas source and the low-pressure gas source, wherein the high-pressure gas source is connected to the high-pressure ventilation chamber 3 through a pressure reducing valve 9, and the pressure reducing valve 9 is used to control the air flow pressure. A sealing structure is provided between the pressure chamber 4 and the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 to ensure the sealing between the pressure chamber 4 and the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5. The high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 are respectively provided with two exhaust ports for discharging the high-pressure gas in the pressure chamber 4.

[0029] The cylindrical rotary valve 1 has the same diameter as the through holes in the pressure chamber 4 and the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5. The interiors of the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 are cross-shaped air paths that intersect vertically and have the same inner diameter. The outer sleeve 2 has air holes in the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5, and the diameter of the air holes is the same as the inner diameter of the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5.

[0030] The cylindrical rotary valve 1 has air holes at the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5. Through the rotation of the cylindrical rotary valve 1, the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 are alternately connected to the corresponding high-pressure gas source and low-pressure gas source. The air holes at the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 are opened in a form of 45° difference. The openings of the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 satisfy that the ratio of the outer diameter circumference of the cylindrical rotary valve 1 occupied by the openings to the circumference occupied by the non-openings is 1:3.

[0031] The interior of the pressure chamber 4 is composed of eight circumferentially evenly distributed air holes, four of which are oriented in the same direction as the high-pressure ventilation chamber 3 , and the other four are oriented in the same direction as the low-pressure ventilation chamber 5 . The outer sleeve 2 has air holes at the pressure chamber 4 , and the diameter of the air holes is twice that of the air holes inside the pressure chamber 4 .

[0032] The working process of the mechanical high cycle gas pressure fatigue testing machine of the embodiment of the present invention is as follows:

[0033] According to the requirements of the pressure fatigue test, the high-pressure gas source is set as the upper pressure limit, and the low-pressure gas source is set as the lower pressure limit. In the initial state, the low-pressure ventilation chamber 5 is connected to the pressure chamber 4 by controlling the servo motor 8. Since there is a phase difference between the air holes of the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5, the high-pressure ventilation chamber 3 is disconnected from the corresponding high-pressure gas source at this time, and the pressure of the pressure chamber 4 is the same as the pressure of the low-pressure gas source. The servo motor 8 is rotated at a constant speed. When the cylindrical rotary valve 1 rotates 45°, the air inlet of the high-pressure ventilation chamber 3 is opened, and the high-pressure gas source is connected to the pressure chamber 4, generating a rapidly rising pressure wave. In the process of the cylindrical rotary valve 1 rotating from 45° to 90°, the air inlet of the high-pressure ventilation chamber 3 is closed, and the exhaust ports of the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 are opened to discharge the excess gas in the pressure chamber 4, so that the gas in the pressure chamber 4 is restored to the same pressure value as the low-pressure gas source, thereby completing a dynamic signal cycle.

[0034] As a result, the high-pressure ventilation chamber 3 and the low-pressure ventilation chamber 5 are alternately connected to the pressure chamber 4, thereby generating an alternating dynamic pressure signal in the pressure chamber 4. By changing the rotation speed of the servo motor 8, the frequency of the dynamic signal can be adjusted, and the number of cycles of the pressure in the pressure chamber 4 is calculated according to the test frequency and test time. When the number of cycles reaches the test requirement, the motor is stopped and the test is completed. The speed v (r / min) of the servo motor 8 is determined according to the required pressure pulsation frequency f (Hz), and the servo motor 8 is rotated at a constant speed, where f = 4v / 60.

[0035] To sum up, the mechanical high-cycle gas pressure fatigue testing machine of the embodiment of the present invention is used for gas pressure fatigue testing, has good sealing and high stability, can generate a dynamic pressure signal with a high cycle and a high pressure upper limit, and can adjust the high pressure upper limit and the low pressure lower limit through the gas supply system to achieve adjustment of the dynamic pressure waveform.

[0036] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A mechanical high cycle gas pressure fatigue testing machine, characterized in that: It includes a cylindrical rotary valve, an outer sleeve, a high-pressure ventilation chamber, a pressure chamber, a low-pressure ventilation chamber, a sealing end cover, a cross coupling, and a servo motor; The cylindrical rotary valve is installed in the outer sleeve and can rotate in the outer sleeve. A sealing end cap is provided on the inner side of the end of the cylindrical rotary valve. The outer side of the end of the cylindrical rotary valve is connected to the servo motor through the cross coupling. The servo motor is used to drive the cylindrical rotary valve to rotate. A high-pressure ventilation chamber, a pressure chamber and a low-pressure ventilation chamber are arranged in sequence on the cylindrical rotary valve, and the test piece is arranged in the pressure chamber. The high-pressure ventilation chamber and the low-pressure ventilation chamber are respectively provided with two air inlets for connecting the high-pressure gas source and the low-pressure gas source. The cylindrical rotary valve is provided with ventilation holes at the high-pressure ventilation chamber and the low-pressure ventilation chamber. Through the rotation of the cylindrical rotary valve, the high-pressure ventilation chamber and the low-pressure ventilation chamber are alternately connected to the corresponding high-pressure gas source and the low-pressure gas source, and the pressure chamber is alternately connected, thereby applying a periodically changing dynamic pressure to the test piece.

2. The mechanical high cycle gas pressure fatigue testing machine according to claim 1, characterized in that: The ventilation holes at the high-pressure ventilation chamber and the low-pressure ventilation chamber are opened in a form of 45° difference.

3. The mechanical high cycle gas pressure fatigue testing machine according to claim 1 or 2, characterized in that: The interiors of the high-pressure ventilation chamber and the low-pressure ventilation chamber are cross-shaped air paths that intersect vertically and have the same inner diameter. The outer sleeve has air holes at the high-pressure ventilation chamber and the low-pressure ventilation chamber, and the diameter of the air holes is the same as the inner diameter of the high-pressure ventilation chamber and the low-pressure ventilation chamber.

4. The mechanical high cycle gas pressure fatigue testing machine according to claim 1 or 2, characterized in that: The pressure chamber has eight pores evenly distributed along the circumferential direction, four of which are in the same direction as the high-pressure ventilation chamber, and the other four are in the same direction as the low-pressure ventilation chamber. The outer sleeve has pores at the pressure chamber, and the diameter of the pores is twice that of the pores inside the pressure chamber.

5. The mechanical high cycle gas pressure fatigue testing machine according to claim 1 or 2, characterized in that: The openings of the high-pressure ventilation chamber and the low-pressure ventilation chamber satisfy a ratio of 1:3 between the circumference of the outer diameter of the cylindrical rotary valve occupied by the openings and the circumference occupied by the non-openings.

6. The mechanical high cycle gas pressure fatigue testing machine according to claim 1 or 2, characterized in that: A sealing structure is provided between the pressure chamber and the high-pressure ventilation chamber and the low-pressure ventilation chamber, and is used for sealing between the pressure chamber and the high-pressure ventilation chamber and the low-pressure ventilation chamber.

7. The mechanical high cycle gas pressure fatigue testing machine according to claim 6, characterized in that: The sealing structure is a composite sealing system composed of three O-rings and polytetrafluoroethylene filling material.

8. The mechanical high cycle gas pressure fatigue testing machine according to claim 1 or 2, characterized in that: The outer sleeve is connected to the inner cylindrical rotary valve via a high-precision bearing.

9. The mechanical high cycle gas pressure fatigue testing machine according to claim 1 or 2, characterized in that: It also includes a pressure reducing valve, and the high-pressure gas source is connected to the high-pressure ventilation chamber through the pressure reducing valve.

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