High temperature resistant cylinder with integrated cooling channel

Abstract

The application discloses a high-temperature-resistant oil cylinder integrated with cooling flow channels and belongs to the technical field of hydraulic transmission. The oil cylinder mainly comprises an end cover, a cylinder body, a piston and an embedded displacement sensor. The cylinder body is characterized in that a cylinder body heat insulation sleeve is arranged outside the inner wall of the cylinder body, and a cylinder body cooling flow channel is formed between the cylinder body heat insulation sleeve and the inner wall of the cylinder body; the piston is a hollow structure, a piston heat insulation sleeve is arranged outside the piston rod, and a piston cooling flow channel is formed. During reciprocating movement of the oil cylinder, pressure alternation in the working chamber is utilized to drive part of the working medium into the cylinder body cooling flow channel and the piston cooling flow channel for reciprocating circulation. The application does not need to be equipped with an external cooling water jacket or a cooling fan or other energy supply cooling devices, and realizes internal circulation cooling of the working medium by using the actuation of the oil cylinder itself, effectively removes heat generated by the piston friction pair and the embedded sensor, and has the advantages of compact structure, energy saving and high efficiency, prolonged service life of the sealing element and the sensor.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic transmission and servo control technology, specifically relating to a high-temperature resistant oil cylinder that utilizes an internally integrated cooling channel to achieve self-circulation of the working medium. Background Technology

[0002] In recent years, with the development of industrial equipment towards high frequency, high pressure, and high power, hydraulic cylinders generate a large amount of heat during operation due to the throttling of high-pressure hydraulic fluid, the relatively high-speed movement of friction pairs, and internal cavitation. Excessive cylinder temperature can lead to a decrease in hydraulic oil viscosity, an increase in leakage, and accelerated aging and failure of seals (such as Glyd rings and O-rings). It can even cause signal drift or damage to the built-in high-precision displacement sensor due to high temperature.

[0003] Existing methods for cooling hydraulic cylinders typically involve installing water-cooled jackets or air-cooled fins outside the cylinder, or adding a separate circulating cooling pump and heat exchanger to the hydraulic system. While these methods achieve a cooling effect, they have the following significant drawbacks: 1. Requires additional energy supply; 2. Increases the size and weight of the cylinder and the entire hydraulic system, making it difficult to arrange in aerospace or compact engineering machinery; 3. Complex external piping increases the risk of leakage and failure.

[0004] Therefore, there is an urgent need for a high-temperature resistant hydraulic cylinder with a compact structure that does not require external power supply. Summary of the Invention

[0005] The purpose of this invention is to solve the problems in the prior art and propose a high-temperature resistant oil cylinder with integrated cooling channels. Through internal structural design, cooling channels are integrated in the cylinder body and piston, and the reciprocating motion of the oil cylinder during normal operation is used as a power source to achieve internal circulation cooling of the working medium.

[0006] To achieve the above objectives, this invention proposes a high-temperature resistant hydraulic cylinder with integrated cooling channels, comprising an end cap, a cylinder body, a piston, and a displacement sensor. The cylinder body and piston integrate working medium circulation cooling channels, including a cylinder body cooling channel and a piston cooling channel. The cylinder body cooling channel is integrated inside the cylinder body sidewall, and the piston cooling channel is integrated inside the hollow piston. Both the cylinder body cooling channel and the piston cooling channel are connected to the hydraulic working chamber of the cylinder. The cylinder body cooling channel and the piston cooling channel are respectively provided with damping holes, which connect the end of the cooling channel to the hydraulic working chamber in a low-pressure return oil state. When the cylinder is in operation, relying on the fluid pressure difference generated by the reciprocating motion of the piston, the working medium forms a reciprocating circulation flow within the cylinder body cooling channel and the piston cooling channel, absorbing and carrying away heat, thus achieving self-cooling of the cylinder.

[0007] Preferably, the cylinder inner cylinder is provided with a cylinder heat insulation sleeve on the outside, and a spiral gap is formed between the outer wall of the cylinder inner cylinder and the inner wall of the cylinder heat insulation sleeve, which constitutes the cylinder cooling channel; the cylinder heat insulation sleeve is used to isolate the heat of the main oil in the hydraulic working chamber from being directly transferred to the outside.

[0008] Preferably, the piston rod of the piston has a hollow structure, and a piston heat insulation sleeve is coaxially sleeved on its outside. The piston cooling channel is formed between the inner wall of the piston heat insulation sleeve and the outer wall of the piston rod.

[0009] Preferably, a built-in displacement sensor is fixed axially at the center of the end cap. The displacement sensor includes a displacement sensor housing and a displacement sensor core. The displacement sensor extends into the hollow piston rod. The piston cooling channel surrounds the outside of the displacement sensor and is coaxially nested with the displacement sensor. The circulating cooling medium synchronously cools the displacement sensor.

[0010] Preferably, the end of the displacement sensor core is fixed to the end of the piston rod of the piston by a sensor locking nut.

[0011] Preferably, the piston has an annular groove on its outer circumference, and a wear-resistant ring-piston and a Glyd ring-piston are installed in the groove for sealing; a wear-resistant ring-piston rod and a Glyd ring-piston rod are installed on the inner wall of the cylinder. The circulating cooling channel effectively reduces the temperature of the piston and piston rod surface, thereby ensuring that the Glyd ring and wear-resistant ring are in a suitable working temperature range.

[0012] Preferably, the equivalent aperture of the cylinder cooling channel damping hole and the piston cooling channel damping hole is 0.2 mm to 2.0 mm.

[0013] Preferably, the cooling channel is any one of the following: spiral, multiple parallel axial straight grooves, mesh microchannel structure, or wave-shaped channel formed by interlaced protrusions machined on the sleeve.

[0014] Preferably, the cylinder cooling channel is machined on the outside of the cylinder inner cylinder, and the piston cooling channel is machined on the outside of the piston rod; or, the cylinder cooling channel has a spiral groove machined on the inside of the cylinder heat insulation sleeve, and then forms a closed spiral cooling channel through the externally tightly fitted cylinder inner cylinder; or, the piston cooling channel has a spiral groove machined inside the piston heat insulation sleeve, and then is fitted onto the piston rod of the piston.

[0015] Preferably, during the cylinder retraction stroke, the working medium is circulated by the pressure difference between the rodless chamber and the rod chamber in the cylinder cooling channel; during the cylinder extension stroke, the working medium is circulated by the pressure difference between the rod chamber and the rodless chamber in the piston cooling channel; and the cooling medium in the working medium circulation cooling channel is the working medium of the cylinder itself.

[0016] The beneficial effects of this invention are: 1. The present invention provides autonomous cooling without external power supply: using the reciprocating motion of the cylinder itself as power, the internal oil is driven to circulate in the cooling channel, eliminating the need for an external cooling pump and achieving zero-energy autonomous heat dissipation.

[0017] 2. The invention features a highly integrated structure and small size: the cooling channel and heat insulation sleeve are integrated into the cylinder body and piston rod, maintaining the external dimensions of a conventional hydraulic cylinder and greatly saving installation space.

[0018] 3. This invention extends the lifespan of core components: it effectively reduces the temperature of the cylinder inner wall, piston friction pair and built-in displacement sensor, slows down the thermal aging of seals, and improves the signal stability of the built-in sensor and the overall service life of the cylinder.

[0019] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a structural cross-sectional view of the present invention; Figure 2 This is a schematic diagram illustrating the working principle of the present invention; Figure 3 This is a schematic diagram of the spiral cooling channel of the cylinder block of the present invention; Figure 4 This is a schematic diagram of the piston spiral cooling channel of the present invention.

[0021] In the diagram: 1-End cap; 2-Displacement sensor housing; 3-Cylinder cooling channel damping hole; 4-Piston; 5-Piston heat insulation sleeve; 6-Displacement sensor core; 7-Piston cooling channel damping hole; 8-Cylinder inner cylinder; 9-Cylinder heat insulation sleeve; 10-Sensor locking nut; 11-O-ring-sensor; 12-Wear ring-piston rod; 13-Glyd ring-piston rod; 14-Rod chamber oil port; 15-Wear ring-piston; 16-Glyd ring-piston; 17-Rodless chamber oil port; 18-O-ring-sensor housing; 19-O-ring-end cap. Detailed Implementation

[0022] like Figure 1 As shown, the present invention provides an autonomous cooling cylinder based on self-circulation of working medium.

[0023] The core of this invention lies in the arrangement of the cooling channels. The cylinder body adopts a double-layer structure, with an inner pressure-bearing cylinder inner cylinder 8 and an outer cylinder heat insulation sleeve 9. The spiral gap between the two forms the cylinder cooling channel. The piston rod of the piston 4 also adopts a hollow design, and a piston heat insulation sleeve 5 is coaxially mounted on the piston rod. The gap between the two forms the piston cooling channel.

[0024] The hydraulic cylinder is a servo intelligent hydraulic cylinder with an integrated displacement sensor. The displacement sensor housing 2 is fixed to the center of the end cap 1 and extends cantilevered into the inner cavity of the hydraulic cylinder; the displacement sensor core 6 is installed inside the hollow piston rod, and its end is installed at the end of the piston rod of the piston 4 through the sensor locking nut 10. When the piston moves, the core 6 moves relative to the sensor housing 2 with the piston rod, thereby outputting a position electrical signal. In this structure, the piston cooling channel surrounds the sensor.

[0025] A reliable high-pressure seal is required at the piston and cylinder guide sleeve. This invention incorporates a wear-resistant ring (piston 15) on the outer circumference of the piston for guiding and load-bearing functions, and a Glyd ring (piston 16) for bidirectional high-pressure sealing. At the front guide position, a wear-resistant ring (piston rod 12) and a Glyd ring (piston rod 13) are provided. Furthermore, O-rings are installed at all static sealing connections, such as the O-ring (sensor 11).

[0026] The working process and cooling principle are as follows: Combination Figure 1 and Figure 2 As shown, the core of this invention for achieving autonomous circulation cooling of the working medium lies in utilizing the dynamic pressure difference and internal micro-orifice throttling effect during cylinder operation. The cylinder not only has a rod-side port 14 and a rodless-side port 17 for the main working oil to enter and exit, but also constructs an internal circulation heat exchange network composed of cylinder cooling channels and piston cooling channels.

[0027] like Figure 2 As shown, its cyclic cooling process is as follows: 1. The self-circulating cooling system around the cylinder block is shown in the triangular cross-section section of the figure: Cylinder cooling occurs during the cylinder's infeed stroke. High-pressure hydraulic oil enters from the rodless chamber port 17 and is then diverted. The main oil path enters the rodless chamber, pushing the piston in the retraction direction. Simultaneously, some high-pressure, low-temperature hydraulic oil is introduced into the cylinder cooling channel from the inlet. A cylinder cooling channel damping orifice 3 is located at the end of the channel, communicating with the rod chamber port 14, which is in a low-pressure return state. Driven by the inlet and return oil pressure difference, this portion of hydraulic oil flows along the cylinder cooling channel throughout the entire length of the cylinder, absorbing heat. Finally, it is throttled by the cylinder cooling channel damping orifice 3 and discharged into the return oil path, thus achieving cylinder cooling.

[0028] 2. The self-circulating cooling system inside the piston is shown in the square cross-section section of the figure: Piston cooling occurs during the cylinder's outward stroke. High-pressure hydraulic oil enters from the rod chamber port 14 and is then diverted. The main oil path enters the rod chamber, pushing the piston in the outward direction. Simultaneously, some high-pressure, low-temperature hydraulic oil passes through the hollow piston and is introduced into the piston cooling channel through the piston cooling channel inlet. Because a cylinder flow channel damping orifice 7 is located at the end of the channel, and this damping orifice 7 communicates with the rodless chamber port 17, which is in a low-pressure return state, this portion of hydraulic oil, driven by the inlet and return oil pressure difference, flows along the piston cooling channel throughout the entire cylinder length, absorbing heat. Finally, it is throttled through the piston cooling channel damping orifice 7 and discharged into the return oil path, thus achieving piston cooling.

[0029] 3. Thermal isolation and cyclic renewal mechanism: The built-in cylinder heat insulation sleeve 9 and piston heat insulation sleeve 5 in this invention physically isolate the high-temperature medium in the main working chamber from the circulating cold oil in the cylinder cooling channel and piston cooling channel. With each reciprocating motion of the cylinder, the hydraulic oil in the above-mentioned channels is forcibly replaced and renewed.

[0030] Preferably, in order to ensure sufficient cooling flow without significantly affecting the main working performance of the hydraulic cylinder, the orifice design of the cylinder cooling flow channel damping orifice 3 and the piston cooling flow channel damping orifice 7 is one of the key aspects of this invention. The equivalent orifice diameter of the damping orifice is preferably between 0.2 mm and 2.0 mm. When the orifice diameter is less than 0.2 mm, the flow resistance is too high, the cooling medium circulation is insufficient, and the heat dissipation effect is not significant; when the orifice diameter is greater than 2.0 mm, the flow diversion is too large, which will cause pressure loss in the main working chamber of the hydraulic cylinder, affecting its response speed and control accuracy.

[0031] In other embodiments, the cooling channel structure of the present invention can have various variations to adapt to different operating conditions. Figure 3 , Figure 4 This demonstrates a typical cooling channel arrangement method, in which the cylinder block cooling channel is machined on the outside of the cylinder inner cylinder 8, and the piston cooling channel is machined on the outside of the piston 4. Alternatively, the cylinder block cooling channel can have spiral grooves machined inside the cylinder block heat insulation sleeve 9, forming a closed spiral cooling channel through the tightly fitted outer cylinder inner cylinder 8. Similarly, the piston cooling channel can also have spiral grooves machined inside the piston heat insulation sleeve 5, which is then fitted onto the piston 4.

[0032] Furthermore, the cooling channel is not limited to a spiral shape; it can also be multiple parallel axial straight grooves, a mesh microchannel structure, or a wave-shaped channel formed by interlaced protrusions machined on the sleeve. As long as a circulation path connecting the two ends of the working chamber can be formed, it falls within the protection scope of this invention.

[0033] This bypass microcirculation system, based on an internal channel damping design, relies entirely on the actuation pressure of the hydraulic system itself, completely eliminating the need for external water-cooling pumps or air-cooling devices. It not only achieves dual internal and external self-driven cooling, effectively preventing thermal failure of seals and built-in sensors, but also maintains a highly compact servo cylinder structure.

[0034] Through the above-mentioned integrated flow channel structure design, this invention eliminates the need for any external cooling water pumps or fans. Excellent heat dissipation can be achieved solely through the flow of hydraulic oil during equipment operation, greatly improving the reliability and service life of the cylinder, its dynamic seals, and electronic sensors.

[0035] The high-temperature resistant hydraulic cylinder with integrated cooling channels described in this invention is particularly suitable for the following typical high-requirement applications due to its self-cooling performance and compact structure: 1. Aerospace field: such as aircraft control surface actuators and landing gear retraction hydraulic cylinders. These applications have extremely stringent requirements for weight and space, and the working environment is complex. The feature of this invention that does not require an external cooling system has significant advantages.

[0036] 2. High-speed forging and stamping equipment: such as the main cylinder of a servo stamping press. These devices operate at extremely high frequencies, resulting in drastic temperature rises inside the cylinder. The self-cooling capability of this invention effectively ensures the thermal stability and sealing life of the cylinder during high-frequency production.

[0037] 3. Vehicle Engineering: Such as steering cylinders or actuators in active suspension systems of heavy construction machinery. In hot environments or under continuous heavy loads, this invention effectively prevents hydraulic oil overheating, ensuring precise control and system reliability.

[0038] 4. Robotics: such as hydraulic cylinders for joints in large industrial robots or biomimetic robots. These applications require compact joints and fast dynamic response. This invention can solve the localized heat problems caused by the integration of motors or valve blocks without sacrificing space and responsiveness.

[0039] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A high-temperature resistant hydraulic cylinder with integrated cooling channels, comprising an end cap (1), a cylinder body, a piston (4), and a displacement sensor, characterized in that: The cylinder and piston (4) are integrated with working medium circulation cooling channels, which include cylinder cooling channels and piston cooling channels; the cylinder cooling channels are integrated inside the cylinder sidewall, and the piston cooling channels are integrated inside the hollow piston (4). The cylinder cooling channel and piston cooling channel are both connected to the hydraulic working chamber of the oil cylinder. The cylinder cooling channel and piston cooling channel are respectively provided with cylinder cooling channel damping hole (3) and piston cooling channel damping hole (7). The damping hole connects the end of the cooling channel to the hydraulic working chamber in a low-pressure return oil state. When the cylinder is in working condition, the working medium forms a reciprocating circulation flow in the cylinder cooling channel and piston cooling channel by relying on the fluid pressure difference generated by the reciprocating motion of the piston (4), absorbing and carrying away heat, and realizing the self-cooling of the cylinder.

2. The high-temperature resistant hydraulic cylinder with integrated cooling channel according to claim 1, characterized in that: The cylinder inner cylinder (8) is provided with a cylinder heat insulation sleeve (9) on the outside. A spiral gap is formed between the outer wall of the cylinder inner cylinder (8) and the inner wall of the cylinder heat insulation sleeve (9), which constitutes the cylinder cooling channel. The cylinder heat insulation sleeve (9) is used to isolate the heat of the main oil in the hydraulic working chamber from being directly transferred to the outside.

3. The high-temperature resistant hydraulic cylinder with integrated cooling channel according to claim 1, characterized in that: The piston rod of the piston (4) has a hollow structure, and a piston heat insulation sleeve (5) is coaxially sleeved on its outside. The piston cooling channel is formed between the inner wall of the piston heat insulation sleeve (5) and the outer wall of the piston rod.

4. A high-temperature resistant hydraulic cylinder with integrated cooling channels according to claim 1, characterized in that: The end cap (1) has a built-in displacement sensor fixed in the center along the axial direction. The displacement sensor includes a displacement sensor housing (2) and a displacement sensor core (6). The displacement sensor extends into the hollow piston rod. The piston cooling channel surrounds the outside of the displacement sensor and is coaxially nested with the displacement sensor. The circulating cooling medium cools the displacement sensor synchronously.

5. A high-temperature resistant hydraulic cylinder with integrated cooling channels according to claim 4, characterized in that: The end of the displacement sensor core (6) is fixed to the end of the piston rod of the piston (4) by the sensor locking nut (10).

6. A high-temperature resistant hydraulic cylinder with integrated cooling channels according to claim 1, characterized in that: The piston (4) has an annular groove on its outer circumference, and a wear-resistant ring-piston (15) and a Glyd ring-piston (16) for sealing are installed in the groove; a wear-resistant ring-piston rod (12) and a Glyd ring-piston rod (13) are installed on the inner wall of the cylinder. The circulating cooling channel effectively reduces the temperature of the piston (4) and piston rod surface, thereby ensuring that the Glyd ring and wear-resistant ring are in a suitable working temperature range.

7. A high-temperature resistant hydraulic cylinder with integrated cooling channels according to claim 1, characterized in that: The equivalent aperture of the cylinder cooling channel damping hole (3) and the piston cooling channel damping hole (7) is 0.2 mm to 2.0 mm.

8. A high-temperature resistant hydraulic cylinder with integrated cooling channels according to claim 1, characterized in that: The cooling channel can be any one of the following: spiral, multiple parallel axial straight grooves, mesh microchannel structure, or wave-shaped channel formed by interlaced protrusions machined on the sleeve.

9. A high-temperature resistant hydraulic cylinder with integrated cooling channels according to claim 1, characterized in that: The cylinder cooling channel is machined on the outside of the cylinder inner cylinder (8), and the piston cooling channel is machined on the outside of the piston rod of the piston (4); or, the cylinder cooling channel has a spiral groove machined on the inside of the cylinder heat insulation sleeve (9), and then forms a closed spiral cooling channel through the externally tightly fitted cylinder inner cylinder (8); or, the piston cooling channel has a spiral groove machined inside the piston heat insulation sleeve (5), and then is fitted onto the piston rod of the piston (4).

10. A high-temperature resistant hydraulic cylinder with integrated cooling channels according to claim 1, characterized in that: The cylinder cooling channel uses the pressure difference between the rodless chamber and the rod chamber to drive the working medium to circulate during the cylinder retraction stroke; the piston cooling channel uses the pressure difference between the rod chamber and the rodless chamber to drive the working medium to circulate during the cylinder extension stroke; and the cooling medium in the working medium circulation cooling channel is the working medium of the cylinder itself.

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