High-precision displacement sensor mounting structure suitable for ultra-small-diameter space

Abstract

The utility model discloses a high-precision displacement sensor mounting structure suitable for an ultra-small-diameter space, and relates to the technical field of measurement. The displacement sensor is composed of a shell and a sliding rod; a hydraulic piston is fixedly arranged at the tail end of the sliding rod, a piston cylinder is correspondingly arranged on the outer side of the hydraulic piston, one end of the piston cylinder is fixedly connected with the shell, and the other end of the piston cylinder is of an open structure; an outer sliding sleeve is arranged on the outer side of the piston cylinder, one end of the outer sliding sleeve is in sliding sealing fit with the outer surface of the piston cylinder, and the other end of the outer sliding sleeve is of a closed structure. An annular space is reserved between the outer cylindrical surface of the piston cylinder and the inner cylindrical surface of the outer sliding sleeve, and the annular space and other spaces communicated with the annular space are filled with fluid. By setting the ratio of the cross sectional area of the annular space between the piston cylinder and the outer sliding sleeve to the area of the end face of the hydraulic piston, the displacement measurement precision can be improved, or the effect of increasing the measuring range of the displacement sensor is achieved.

Description

Technical Field

[0001] This utility model relates to the field of measurement technology, and in particular to a high-precision displacement sensor mounting structure suitable for use in spaces with ultra-small diameters. Background Technology

[0002] Currently, displacement sensors are widely used in mechanical devices such as micro-robots and micro-instruments. However, with the miniaturization and precision evolution of related devices, the requirements for the installation space of displacement sensors are becoming increasingly stringent, and requirements for the accuracy or measurement range of displacement sensors are being placed on different scenarios.

[0003] Therefore, it is necessary to design a displacement sensor mounting structure that can be installed in a space with an ultra-small diameter. Utility Model Content

[0004] This invention provides a high-precision displacement sensor mounting structure suitable for ultra-small diameter spaces, with the aim of reducing the diameter space occupied by the displacement sensor and promoting the development of equipment towards miniaturization and precision.

[0005] The technical problem solved by this utility model is achieved by the following technical solution: This utility model provides a high-precision displacement sensor mounting structure suitable for ultra-small diameter spaces, including a displacement sensor composed of a shell and a slide rod, with the slide rod slidably mounted at the center of the shell;

[0006] A hydraulic piston is fixedly installed at the end of the slide rod, and a piston cylinder is correspondingly installed on the outside of the hydraulic piston. The inner wall of the piston cylinder is in sliding sealing fit with the piston. One end of the piston cylinder is fixedly connected to the outer shell, and the other end is an open structure.

[0007] An outer sliding sleeve is provided on the outside of the piston cylinder. One end of the outer sliding sleeve is slidably sealed with the outer surface of the piston cylinder, and the other end is a closed structure.

[0008] An annular space is left between the outer cylindrical surface of the piston cylinder and the inner cylindrical surface of the outer sliding sleeve. This annular space and other spaces connected to it are filled with fluid that can transmit pressure.

[0009] The annular cross-sectional area of ​​the annular space is larger than the area of ​​the piston end face.

[0010] As an alternative, the annular cross-sectional area of ​​the annular space is larger than the area of ​​the piston end face.

[0011] As a preferred embodiment, a vent hole is provided on one end of the piston cylinder facing the outer shell, which can connect the inner and outer spaces of the piston cylinder.

[0012] As a preferred embodiment, the closed end of the outer sleeve is provided with a connecting external thread.

[0013] As a preferred embodiment, the closed end of the outer sliding sleeve is provided with an oil injection hole, which is located on the end face of the closed end of the outer sliding sleeve and is sealed by a plug.

[0014] As a preferred embodiment, the outer diameter of the outer shell is the same as the outer diameter of the outer sliding sleeve.

[0015] As a preferred embodiment, the fluid is oil or grease.

[0016] The beneficial effects of this utility model are:

[0017] This invention connects a hydraulic amplification mechanism, comprising a hydraulic piston, a piston cylinder, and an outer sliding sleeve, to the end of a displacement sensor. Depending on the implementation, it can produce two effects: First, when the ratio of the cross-sectional area of ​​the annular space between the piston cylinder and the outer sliding sleeve to the end face area of ​​the hydraulic piston is greater than 1, a unit displacement input can cause the sliding rod to produce a displacement change greater than one unit, thereby improving the measurement accuracy of the displacement sensor and making it suitable for applications requiring high measurement accuracy. Second, when the ratio is less than 1, a unit displacement input can cause the sliding rod to produce a displacement change less than one unit, thereby increasing the range of the displacement sensor and making it suitable for applications with limited installation space but high range requirements. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0019] In the diagram: 1. Cable; 2. Housing; 3. Slide rod; 4. Piston cylinder; 5. Fluid; 6. Outer sliding sleeve; 7. Hydraulic piston; 8. Plug; 9. Connecting external thread. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Example 1: High-precision measurement mode

[0022] like Figure 1 As shown, this embodiment includes a displacement sensor consisting of a housing 2 and a sliding rod 3. The sliding rod 3 is slidably mounted at the center of the housing 2. A signal conversion device (such as a sliding rheostat) capable of converting displacement changes into electrical signal changes is disposed between the housing 2 and the sliding rod 3. The signal conversion device outputs the electrical signal reflecting the displacement change through a cable 1. The above structure is a common structure of displacement sensors and will not be described in detail here.

[0023] like Figure 1As shown, in this embodiment, a hydraulic piston 7 is fixedly mounted at the end of the slide rod 3, and a piston cylinder 4 is correspondingly mounted on the outer side of the hydraulic piston 7. The inner wall of the piston cylinder 4 is in sliding sealing cooperation with the piston. One end of the piston cylinder 4 is fixedly connected to the outer shell 2, and the other end is an open structure. Simultaneously, in this embodiment, an outer sliding sleeve 6 is mounted on the outer side of the piston cylinder 4. One end of the outer sliding sleeve 6 is in sliding sealing cooperation with the outer surface of the piston cylinder 4, and the other end is a closed structure. An annular space is left between the outer cylindrical surface of the piston cylinder 4 and the inner cylindrical surface of the outer sliding sleeve 6. This annular space and other spaces connected to it are filled with a fluid 5 capable of transmitting pressure.

[0024] The purpose of the above structure is to create a sealed space between the outer sliding sleeve 6, the piston cylinder 4 and the hydraulic piston 7. By filling this sealed space with hydraulic oil or grease or sealing grease that flows easily when squeezed by the outer sliding sleeve 6, the linear motion of the outer sliding sleeve 6 is converted into the linear motion of the hydraulic piston 7 and the slide rod 3.

[0025] In this embodiment, in order to achieve high-precision measurement, the cross-sectional area of ​​the annular space between the piston cylinder 4 and the outer sliding sleeve 6 is larger than the area of ​​the piston end face. In this case, a unit displacement input can cause the slide rod 3 to produce a displacement change of more than one unit, thereby improving the measurement accuracy of the displacement sensor and making it suitable for application scenarios with high measurement accuracy requirements.

[0026] like Figure 1 As shown in this embodiment, a vent hole is provided on one end of the piston cylinder 4 facing the outer shell 2. The vent hole can connect the inner and outer spaces of the piston cylinder 4. When it is hydraulically driven, the air on the other side of the hydraulic piston 7 can be discharged in time through the vent hole, thereby avoiding obstruction to the hydraulic piston 7.

[0027] like Figure 1 As shown, in this embodiment, the closed end of the outer sliding sleeve 6 is provided with a connecting external thread 9.

[0028] like Figure 1 As shown, in this embodiment, the closed end of the outer sliding sleeve 6 is provided with an oil injection hole, which is located on the end face of the closed end of the outer sliding sleeve 6 and is sealed by a plug 8.

[0029] The specific structural parameters are as follows:

[0030] The hydraulic piston 7 has a diameter of φ5mm, an effective stroke of 5mm, and a surface hard chrome plated (Ra≤0.05μm); the outer sleeve 6 has an inner diameter of φ6mm, the piston cylinder 4 has an outer diameter of φ5mm, and the annular cross-sectional area ratio = π*(6²-5²) / π*5² = 1.56 (>1); the fluid 5 uses low-viscosity silicone oil (kinematic viscosity 20cSt@25℃) and a filling pressure of 0.3MPa; the sealing structure uses a Step seal + O-ring combination seal with a pressure resistance rating of 30MPa.

[0031] Technical requirements:

[0032] The piston cylinder 4 and the outer sliding sleeve 6 are made by wire cutting and grinding, and the fit gap is controlled within 5μm. The shell is made of indium steel alloy (thermal expansion coefficient 10.6×10^-6 / K) to match the expansion coefficient of the fluid medium 5 (about 7×10^-4 / K). The front end of the outer sliding sleeve 6 is equipped with a labyrinth dustproof ring, which is used in conjunction with a compressed air purging device (flow rate 0.1L / min).

[0033] Working principle:

[0034] When the outer sliding sleeve 6 moves by Δx under external thrust, the volume change of the annular space is ΔV = π*(6²-5²)Δx = 11πΔx. Since the ratio of the annular cross-sectional area to the piston area is 1.56, according to Pascal's principle, the output displacement of the hydraulic piston 7 is Δy = ΔV / A_piston = (11πΔx) / (π2.5²) = 1.76Δx, achieving a displacement amplification factor of 1.76. Under the same conditions, the measurement accuracy of the displacement sensor is also amplified by the same factor, thereby improving the measurement accuracy.

[0035] Example 2: Large Stroke Extension Mode

[0036] In this embodiment, by setting the dimensions of each component, the annular cross-sectional area of ​​the annular space is made smaller than the area of ​​the piston end face. In this case, a unit displacement input can cause the slide rod 3 to produce a displacement change of less than one unit, thereby increasing the range of the displacement sensor. This is suitable for application scenarios where the installation space is small but the range requirement is high.

[0037] The specific working principle is similar to that of Embodiment 1, and will not be repeated here.

[0038] Implementation Notes:

[0039] 1. The selection of seals must match the chemical compatibility of the working medium.

[0040] 2. Hydraulic oil needs to be changed regularly (it is recommended to change it every 5,000 hours).

[0041] 3. During installation, ensure that the concentricity between the axis of the outer sliding sleeve 6 and the outer shell 2 is ≤0.01mm.

[0042] 4. For long-term storage, apply rust-preventive oil and provide nitrogen protection.

[0043] As can be seen from the above embodiments, the present invention, through its innovative hydraulic amplification mechanism and modular design, achieves multi-dimensional measurement capabilities ranging from high precision to large stroke while maintaining an ultra-small diameter, making it particularly suitable for high-end testing scenarios in fields such as medical devices, aerospace, and precision manufacturing.

Claims

1. A high-precision displacement sensor mounting structure suitable for use in an ultra-small diameter space, comprising a displacement sensor composed of a housing (2) and a slide rod (3), the slide rod (3) being slidingly mounted in the center of the housing (2), characterized in that: a hydraulic piston (7) is fixedly arranged at the end of the slide rod (3), and a piston cylinder (4) is correspondingly arranged on the outside of the hydraulic piston (7), the inner wall of the piston cylinder (4) being in sliding sealing cooperation with the hydraulic piston (7), one end of the piston cylinder (4) being fixedly connected with the housing (2), and the other end being in an open structure; an outer slide sleeve (6) is arranged on the outside of the piston cylinder (4), one end of the outer slide sleeve (6) being in sliding sealing cooperation with the outer surface of the piston cylinder (4), and the other end being in a closed structure; an annular space is left between the outer cylindrical surface of the piston cylinder (4) and the inner cylindrical surface of the outer slide sleeve (6), and the annular space and other spaces in communication therewith are filled with a fluid (5) capable of conducting pressure; the annular cross-sectional area of the annular space is greater than the area of the piston end face. Alternatively, the annular cross-sectional area of the annular space is greater than the area of the piston end face.

2. The high-precision displacement sensor mounting structure suitable for use in an ultra-small diameter space according to claim 1, characterized by: An air vent is arranged on the end of the piston cylinder (4) facing the housing (2), and the air vent is capable of communicating the space inside and outside the piston cylinder (4).

3. The high-precision displacement sensor mounting structure for use in an ultra-small diameter space according to any one of claims 1 or 2, characterized by: A connecting external thread (9) is arranged on the closed end of the outer slide sleeve (6).

4. The high-precision displacement sensor mounting structure for use in an ultra-small diameter space according to any one of claims 1 or 2, characterized by: An oil injection hole is arranged on the closed end of the outer slide sleeve (6), and the oil injection hole is arranged on the end face of the closed end of the outer slide sleeve (6) and is sealed by a grommet (8).

5. The high-precision displacement sensor mounting structure for use in an ultra-small diameter space according to any one of claims 1 or 2, characterized by: The outer diameter of the housing (2) is the same as the outer diameter of the outer slide sleeve (6).

6. The high-precision displacement sensor mounting structure for use in an ultra-small diameter space according to any one of claims 1 or 2, characterized by: The fluid (5) is oil or grease.

7. The high-precision displacement sensor mounting structure for use in an ultra-small diameter space according to any one of claims 1 or 2, characterized by: ​

Images