Oil pressure monitoring and protecting device

Abstract

The utility model belongs to the field of switches operated according to changes of fluid pressure, and particularly relates to an oil pressure monitoring and protecting device. The cylinder and the valve seat are fixed to the upper portion and the lower portion of the valve body through bolts, a guide sleeve is installed between the valve body and the cylinder, the valve body is provided with a valve cavity, and an oil inlet hole and an oil outlet hole which are communicated with the valve cavity are formed in the valve seat. A pushing assembly used for plugging the oil discharge hole when the oil pressure in the valve cavity is low and being pushed by oil to move to open the oil discharge hole when the oil pressure is high is installed in the guide sleeve, a moving piece pushed by the pushing assembly is installed on the cylinder body, and a control switch triggered when the oil pressure reaches a set value is installed on the moving piece and / or the cylinder body. The guide sleeve comprises a large-diameter section and a small-diameter section, the large-diameter section is located in the valve body, the small-diameter section is located in the cylinder body, a step face between the large-diameter section and the small-diameter section and the end face of the valve body abut against the end face of the cylinder body at the same time, and a step stopping the end face of the large-diameter section is arranged in the valve body. And when the cylinder body and the valve body are connected through bolts, the cylinder body does not incline.

Description

Technical Field

[0001] The utility model relates to an oil pressure monitoring and protection device, belonging to the field of switches operated by the change of fluid pressure. Background Art

[0002] In an oil pressure operating mechanism, the oil pressure monitoring and protection device is an indispensable part, mainly playing the roles of monitoring oil pressure, overloading protection and high-pressure alarm. In the existing oil pressure monitoring and protection devices, for example, a mechanical oil pressure switch disclosed in a Chinese utility model patent with the authorization publication number of CN201369292Y and the authorization publication date of December 23, 2009. This mechanical oil pressure switch (i.e., the oil pressure monitoring and protection device) includes a base, a valve seat and a switch part arranged on the base. The valve seat is provided with an oil inlet hole and an oil discharge hole communicated with the oil inlet hole and the oil return hole on the base. The switch part includes a top cover (i.e., a cover plate), an adjusting gasket, a spring cylinder (i.e., a cylinder body), a combined spring (i.e., a disc spring), a guide post (i.e., a guiding post), a contact (i.e., a contact in the control switch), a support plate, a switch, a piston, a steel ball and a sealing structure.

[0003] Among them, the control switch includes a contact and a switch. The guide post and the support plate form a moving part. The steel ball is located between the piston and the guide post and is closely attached to the bottom of the guide post. The combined spring and the support plate are sleeved on the guide post from top to bottom. Multiple switches are installed on the support plate. The contact is connected to the circuit and corresponds to the switch contact respectively. The spring cylinder covers the outside of the combined spring. The top cover is installed at the upper end of the spring cylinder, and the adjusting gasket is located between the top cover and the combined spring. The upper end of the guide post is installed in the central hole of the top cover. The upper part of the valve seat is provided with a valve body. A cylinder sleeve (i.e., a guiding sleeve) is arranged at one end of the valve body away from the valve seat. The upper end of the cylinder sleeve is hermetically sleeved with a cylinder body. The lower end of the cylinder sleeve is inserted into the upper end of the valve body. The piston is installed in the cylinder sleeve, and the lower end of the piston is movably inserted into the valve cavity of the valve body. A guiding rod is movably inserted into the piston. The guiding rod and the piston form a pushing component. The guiding rod has a structure that is thin in the middle and thick at both ends. A snap ring that can move on the middle part of the guiding rod is installed at the bottom of the piston. A sealing gasket is installed at the thicker part at the lower end of the guiding rod through a nut. The sealing gasket can seal the inner opening of the oil discharge hole. The thicker part at the upper end of the guiding rod is located inside the piston and forms a limiting structure for the movement of the snap ring. A spring is arranged between the upper end of the guiding rod and the inner wall of the upper end of the piston.

[0004] An oil passage hole is provided on the guide rod. During use, the oil fluid enters the valve body from the oil inlet hole and enters the inner hole of the piston through the oil passage hole on the guide rod. At this time, due to the area difference between the guide rod and the nut, the thicker part below the guide rod is subjected to a downward pressure. At the same time, under the action of the spring at the upper end of the guide rod, the sealing gasket can well block the oil discharge hole on the valve seat. When the oil pressure continues to rise, the oil fluid pushes the piston upward, and then pushes the guide post, the support plate and the switch upward. After the oil pressure reaches the set value, the switch contacts the contact point, and the control switch transmits the oil pressure signal outward. When the oil pressure exceeds the set value, the piston will drive the guide rod upward together through the snap ring, so that the sealing gasket at the lower end of the guide rod leaves the oil discharge hole, and then the oil fluid is discharged outward until the oil pressure drops to the set value, and the switch remains in contact with the contact point until the oil pressure is lower than the set value.

[0005] However, an annular boss is provided on the guide sleeve in the above oil pressure monitoring and protection device. The annular boss is located between the cylinder body and the valve body. There is a gap between the lower end face of the cylinder body and the upper end face of the valve body. The lower end face of the cylinder body only fits with the annular boss with a smaller area, that is, a large area of the end face of the cylinder body is suspended. When the cylinder body and the valve body are fixedly connected by bolts, if the tightening degrees of multiple bolts are inconsistent, it will cause the cylinder body to be skewed together with the guide sleeve, that is, the guide sleeve is not coaxial with the valve body, which will affect the smooth movement of the piston and even cause the guide rod to be skewed, thereby affecting the sealing effect of the sealing gasket on the oil discharge hole. Utility Model Content

[0006] The purpose of the present utility model is to provide an oil pressure monitoring and protection device to solve the problem that in the existing oil pressure monitoring and protection device, an annular boss is provided in the middle of the guide sleeve, which causes a large area of the cylinder body to be suspended. When the tightening degrees of multiple bolts are inconsistent, it will cause the cylinder body to be skewed and the guide sleeve to be skewed, affecting the smooth movement of the top push assembly and the sealing effect of the oil discharge hole.

[0007] To achieve the above purpose, the oil pressure monitoring and protection device in the present utility model adopts the following technical solutions:

[0008] An oil pressure monitoring and protection device includes a valve body, a cylinder body and a valve seat fixed to the upper and lower parts of the valve body by bolts. A guide sleeve is installed between the valve body and the cylinder body. The valve body has a valve cavity. An oil inlet hole and an oil discharge hole communicating with the valve cavity are provided on the valve seat. A top push assembly is installed in the guide sleeve for blocking the oil discharge hole when the oil pressure in the valve cavity is low and being pushed by the oil fluid to move and open the oil discharge hole when the oil pressure is high. A moving part pushed by the top push assembly is installed on the cylinder body. A control switch triggered when the oil pressure reaches the set value is installed on the moving part and / or the cylinder body. The guide sleeve includes a large-diameter section and a small-diameter section. The large-diameter section is located in the valve body, and the small-diameter section is located in the cylinder body. The stepped surface between the large-diameter section and the small-diameter section and the end face of the valve body are simultaneously abutted against the end face of the cylinder body. A step for blocking the end face of the large-diameter section is provided in the valve body.

[0009] The beneficial effects of the above technical solution are as follows: The present utility model belongs to an invention and creation with a changed element relationship, which changes the shape and installation position of the guide sleeve. The guide sleeve includes a large-diameter section and a small-diameter section, with its large-diameter section located inside the valve body and its small-diameter section located inside the cylinder body. There is a step in the valve body that abuts against the end face of the large-diameter section. During installation, the lower end of the guide sleeve can be pressed against the step surface to ensure the firm position of the guide sleeve. The step surface formed between the large-diameter section and the small-diameter section and the end face of the valve body are simultaneously in contact with the end face of the cylinder body. Therefore, when the valve body and the cylinder body are fixedly connected by bolts, the end face of the cylinder body can be directly and completely fitted with the end face of the valve body. Thus, even if the screwing degrees of multiple bolts are inconsistent, it can ensure the fitting of the end face of the cylinder body and the end face of the valve body, preventing the cylinder body from tilting, and further preventing the guide sleeve and the pushing assembly from tilting, ensuring the smooth up and down movement of the pushing assembly, and at the same time ensuring the sealing effect on the oil discharge hole.

[0010] Further, a first sealing ring is provided between the outer peripheral surface of the large-diameter section and the inner wall of the valve body.

[0011] Further, a first annular groove is formed on the outer peripheral surface of the large-diameter section, and the first sealing ring is installed in the first annular groove and is in sealing cooperation with the inner wall of the valve body.

[0012] Further, a second sealing ring is provided between the outer peripheral surface of the small-diameter section and the inner wall of the cylinder body.

[0013] Further, a second annular groove is formed on the outer peripheral surface of the small-diameter section, and the second sealing ring is installed in the second annular groove and is in sealing cooperation with the inner wall of the cylinder body.

[0014] Further, a dust-proof ring is installed in the inner hole of the guide sleeve, and the dust-proof ring is located at the end of the small-diameter section.

[0015] Further, the pushing assembly includes a piston that is in guiding cooperation with the inner hole of the guide sleeve and a guide rod with one end extending into the inner hole of the piston. A sealing pad for blocking the oil discharge hole is provided at the other end of the guide rod. A first spring is installed between the end of the guide rod extending into the inner hole of the piston and the bottom of the inner hole of the piston. A communication hole communicating the valve cavity and the inner hole of the piston is provided on the guide rod. A shoulder is provided on the outer periphery of the guide rod. A circlip is installed at the orifice position of the inner hole of the piston, and the circlip is used to be in blocking cooperation with the shoulder and drive the guide rod to move upward together when the piston moves upward to a certain extent.

[0016] Further, an annular boss is provided on the inner wall of the valve body. A spring seat is installed at the end of the large-diameter section. One end of the spring seat extends into the inside of the large-diameter section, and a third sealing ring is clamped between the spring seat and the large-diameter section. A second spring is installed between the other end of the spring seat and the annular boss. The third sealing ring is in sealing cooperation with the outer peripheral surface of the piston.

[0017] Further, a stepped hole is provided in the end portion of the large-diameter section for the spring seat to extend into. The stepped hole includes a large-diameter hole and a small-diameter hole. The spring seat includes a large-head section and a small-head section. The small-head section extends into the small-diameter hole, the large-head section extends into the large-diameter hole, and the third sealing ring is located in the small-diameter hole.

[0018] Further, a cover plate is installed at one end of the cylinder away from the valve body, and a disc spring is installed between the moving part and the cover plate. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of an embodiment of the oil pressure monitoring and protection device of the present invention;

[0020] Figure 2 is an assembly schematic diagram of the guide sleeve, spring seat and third sealing ring in the embodiment of the oil pressure monitoring and protection device of the present invention.

[0021] In the figure: 1. First bolt; 2. Cover plate; 3. Cylinder; 4. First sealing ring; 5. Third sealing ring; 6. Second bolt; 7. First spring; 8. Snap ring; 9. Valve seat; 10. Nut; 11. Third bolt; 12. Gasket; 13. Valve body; 14. Guide rod; 15. Second spring; 16. Spring seat; 161. Large-head section; 162. Small-head section; 17. Guide sleeve; 171. Large-diameter section; 1711. Large-diameter hole; 1712. Small-diameter hole; 172. Small-diameter section; 18. Piston; 19. Second sealing ring; 20. Dust-proof ring; 21. Steel ball; 22. Travel switch; 23. Support plate; 24. Trigger rod; 25. Micro switch; 26. Disc spring; 27. Guide post; 28. Adjusting gasket; 29. Guide seat; 30. Oil inlet hole; 31. Oil drain hole. Detailed Embodiment

[0022] The features and performance of the present invention will be further described in detail below in conjunction with the embodiments.

[0023] Aiming at the technical problems existing in the prior art, the basic technical concept of the present invention is: removing the annular boss of the guide sleeve, and the guide sleeve is set to be composed of a large-diameter section and a small-diameter section. The stepped surface between the large-diameter section and the small-diameter section and the end surface of the valve body can be in contact with the end surface of the cylinder at the same time. Therefore, when tightened by bolts, the cylinder will not be skewed, and thus the guide sleeve will not be skewed either, further ensuring the smooth up and down movement of the jacking assembly and at the same time ensuring the sealing effect on the oil drain hole.

[0024] An embodiment of the oil pressure monitoring and protection device in the present invention:

[0025] Such as Figure 1As shown, the oil pressure monitoring and protection device includes a valve body 13, a cylinder 3 and a valve seat 9 that are fixed to the upper and lower parts of the valve body 13 by bolts. Specifically, the cylinder 3 and the upper part of the valve body 13 are fixedly connected by a second bolt 6, and the valve seat 9 and the lower part of the valve body 13 are fixedly connected by a third bolt 11. The valve body 13 has a valve cavity. An oil inlet hole 30 and an oil drain hole 31 communicating with the valve cavity are provided on the valve seat 9. The hydraulic oil in the hydraulic system enters the valve cavity through the oil inlet hole 30, that is, enters the oil pressure monitoring and protection device.

[0026] A guide sleeve 17 is installed between the valve body 13 and the cylinder 3. A push component is installed in the guide sleeve 17 for blocking the oil drain hole 31 when the oil pressure in the valve cavity is low and being pushed by the oil to move and open the oil drain hole 31 when the oil pressure is high. In this embodiment, the push component includes a piston 18 that is guided and fitted with the inner hole of the guide sleeve 17 and a guide rod 14 with one end extending into the inner hole of the piston 18. A steel ball 21 is provided at the top of the piston 18. A sealing pad 12 for blocking the oil drain hole 31 is provided at the other end of the guide rod 14. A first spring 7 is installed between the end of the guide rod 14 extending into the inner hole of the piston 18 and the bottom of the inner hole of the piston 18. A communication hole (not marked in the figure) communicating the valve cavity of the valve body 13 and the inner hole of the piston 18 is provided on the guide rod 14. A shoulder (not marked in the figure) is provided on the outer periphery of the guide rod 14. A snap ring 8 is installed at the orifice position of the inner hole of the piston 18. The snap ring 8 is used to engage with the shoulder to stop and drive the guide rod 14 to move upward together when the piston 18 moves upward to a certain extent. A boss is provided at the lower end of the guide rod 14. The boss is threadedly connected with a nut 10. Specifically, an external thread is provided on the boss, and an internal thread is provided on the nut 10. A sealing pad 12 is clamped between the nut 10 and the boss of the guide rod 14. A through hole is provided on the nut 10. Specifically, the through hole is located at the center of the nut 10. The oil drain hole 31 protrudes from the inner wall of the valve body 13 and passes through the above-mentioned through hole to contact the sealing pad 12 and is blocked by the sealing pad 12 to ensure that the hydraulic oil will not be discharged from the oil drain hole 31.

[0027] As Figure 1 and Figure 2As shown, the guide sleeve 17 includes a large-diameter section 171 and a small-diameter section 172. The large-diameter section 171 is located inside the valve body 13, and the small-diameter section 172 is located inside the cylinder body 3. A dust-proof ring 20 is installed in the inner hole of the guide sleeve 14. The dust-proof ring 20 is located at the end of the small-diameter section 172 to prevent impurities from entering the valve cavity of the valve body 13 and affecting the quality of the hydraulic oil. The stepped surface between the large-diameter section 171 and the small-diameter section 172, and the end surface of the valve body 13 are simultaneously in contact with the end surface of the cylinder body 3. There is a step (not marked in the figure) in the valve body 13 that abuts against the end surface of the large-diameter section 171. Thus, when the cylinder body 3 and the valve body 13 are fixedly connected by the second bolts 6, the end surface of the cylinder body 3 is completely fitted with the end surface of the valve body 13. At this time, even if the tightening degrees of the multiple second bolts 6 are different, it will not affect the contact between the end surface of the cylinder body 3 and the end surface of the valve body 13, and the cylinder body 3 will not be skewed. Furthermore, it will not cause the guide sleeve 17 and the piston 18 to be skewed, making the guide sleeve 17 coaxial with the valve body 13 and ensuring that the piston 18 can move smoothly.

[0028] In this embodiment, a first sealing ring 4 is provided between the outer peripheral surface of the large-diameter section 171 and the inner wall of the valve body 13. Specifically, a first annular groove (not marked in the figure) is provided on the outer peripheral surface of the large-diameter section 171, and the first sealing ring 4 is installed in the first annular groove and is in sealing cooperation with the inner wall of the valve body 13 to prevent the hydraulic oil from leaking out between the large-diameter section 171 and the valve body 13. A second sealing ring 19 is provided between the outer peripheral surface of the small-diameter section 172 and the inner wall of the cylinder body 3. Specifically, a second annular groove (not marked in the figure) is provided on the outer peripheral surface of the small-diameter section 172, and the second sealing ring 19 is installed in the second annular groove and is in sealing cooperation with the inner wall of the cylinder body 3. When the piston 18 moves up and down, some hydraulic oil may enter the cylinder body 3. The installation of the second sealing ring 19 can ensure that this part of the hydraulic oil will not leak out between the small-diameter section 172 and the cylinder body 3. At the same time, even if the guide sleeve 17 is skewed, it will not cause the first sealing ring 4 and the second sealing ring 19 to fail, and even improve the sealing performance. Furthermore, it ensures the sealing effect between the large-diameter section 171 and the valve body 13, and between the small-diameter section 172 and the cylinder body 3, and ensures the sealing performance of the entire device.

[0029] As Figure 2 shown, a spring seat 16 is installed at the lower end of the large-diameter section 171. Specifically, a stepped hole is provided in the part of the end of the large-diameter section 171 for the spring seat 16 to extend into. The stepped hole includes a large-diameter hole 1711 and a small-diameter hole 1712. The spring seat 16 includes a large-head section 161 and a small-head section 162. The small-head section 162 extends into the small-diameter hole 1712, and the large-head section 161 extends into the large-diameter hole 1711. A third sealing ring 5 is clamped between the upper end of the spring seat 16 and the large-diameter section 171. The third sealing ring 5 is located in the small-diameter hole 1712. As Figure 1As shown, the third sealing ring 5 is in sealing fit with the outer peripheral surface of the piston 18 to ensure the sealing performance between the guide sleeve 17 and the piston 18. During installation, the third sealing ring 5 can be directly inserted from the end of the large-diameter section 171, and then the spring seat 16 can be inserted. The installation is simple and convenient. An annular boss is provided on the inner wall of the valve body 13, and a second spring 15 is installed between the annular boss and the spring seat 16. Thus, the third sealing ring 5 can be pressed tightly through the annular boss, the spring seat 16, and the second spring 15 to ensure the sealing effect between the guide sleeve 17 and the piston 18. At the same time, there is a clearance fit between the piston 18, the spring seat 16, and the second spring 15. Therefore, when the piston 18 moves downward, the spring seat 16 will not move, that is, it will not affect the sealing effect of the third sealing ring 5.

[0030] As Figure 1 shown, a moving member pushed by the pushed component is installed on the cylinder body 3. In this embodiment, the moving member includes a guiding column 27 arranged separately and a supporting plate 23 fixed to the lower end of the guiding column 27. Specifically, a groove for accommodating the upper hemisphere of the steel ball 21 is provided at the bottom of the guiding column 27. The guiding column 27 is coaxial with the cylinder body 3. The guiding column 27 is a stepped shaft, including a small stepped shaft at the upper part, a medium stepped shaft in the middle, and a large stepped shaft at the lower part. The large stepped shaft is located below the supporting plate 23, so that the step surface between the large stepped shaft and the medium stepped shaft provides a supporting force for the supporting plate 23. The supporting plate 23 includes a central plate, square plates at both ends, and flat plates connecting the central plate and the square plates at both ends and passing through the cylinder body 3. Among them, a central hole is provided at the central position of the central plate to sleeved the supporting plate 23 on the large stepped shaft below the guiding column 27. The square plates at both ends of the supporting plate 23 are located outside the cylinder body 3. Thus, when the piston 18 drives the steel ball 21 to move upward, the steel ball 21 can automatically align with the groove, and further ensure the alignment of the piston 18 and the guiding column 27, making the guiding column 27 coaxial with the cylinder body 3, and reliably driving the supporting plate 23 to move upward.

[0031] A control switch triggered when the oil pressure is greater than a set value is installed on the moving part and / or the cylinder body 3. In this embodiment, the control switch includes a travel switch 22 and a microswitch 25 respectively connected to a circuit, and the travel switch 22 and the microswitch 25 are used in cooperation. The travel switch 22 includes a push rod trigger rod 24 for contacting the contact on the microswitch 25 to control the on-off states of the travel switch 22 and the microswitch 25 and send an oil pressure signal to the outside. Specifically, two travel switches 22 are provided, which are respectively located on the square plates at both ends of the support plate 23, and the microswitch 25 is fixed above the corresponding travel switch 22. In use, the support plate 23 can drive the travel switch 22 and the push rod 24 to move upward, and change the on and off states of the travel switch 22 and the microswitch 25 when the push rod trigger rod 24 contacts the microswitch 25. In addition, a pair of normally open or normally closed nodes can be provided during specific use for functions such as cutting off the power supply of the motor and monitoring the oil pressure of the hydraulic system. Multiple pairs of microswitches 25 and travel switches 22 can be provided to monitor different oil pressure values.

[0032] A cover plate 2 is installed at one end of the cylinder body 3 far from the valve body 13. A disc spring 26 is installed between the moving part and the cover plate 2. In this embodiment, two disc springs 26 are provided, which are respectively located between the two flat plates of the support plate 23 and the cover plate 2. The cover plate 2 and the cylinder body 3 are fixed by a plurality of first bolts 1. A through hole is provided at the center position of the cover plate 2, and a guide seat 29 is provided in the through hole. The guide seat 29 is in guiding cooperation with the upper small stepped shaft of the guide post 27 to enable the guide post 27 to be in the center position when moving and reliably drive the support plate 23 to move upward. An adjusting gasket 28 is provided between the cover plate 2 and the disc spring 26, and the set maximum pressure value can be adjusted by changing the thickness of the adjusting gasket 28. The thicker the thickness of the adjusting gasket 28, the larger the maximum value.

[0033] Working principle: The oil fluid enters the valve cavity of the valve body 13 through the oil inlet hole 30. As the oil pressure continuously rises, more oil fluid enters the interior of the valve body 13. The oil fluid will enter the inner hole of the piston 18 through the oil passage holes on the guide rod 14, filling the entire inner cavity of the valve body 13. At this time, the contact area between the guide rod 14 and the oil fluid is larger than the combined contact area of the nut and the lower boss of the guide rod 14 with the oil fluid. Meanwhile, under the action of the first spring 7, the sealing gasket 12 seals well at the orifice of the oil drain hole 31. When the oil pressure continuously rises and exceeds the pressure of the disc spring 26, the oil fluid pushes the piston 18 to move upward. The piston 18 drives the steel ball 21 and the guide post 17 to move upward, and the guide post 17 drives the support plate 23 to move upward. At this time, the piston 18, the guide post 17, and the support plate 23 are coaxial. When the oil pressure reaches the set pressure value, the trigger rod 24 on the travel switch 22 contacts the contact point on the micro switch 25, and the control circuit sends out an oil pressure value signal to the outside. When the oil pressure exceeds the set value, the oil fluid will continue to push the piston 18 upward. At this time, the piston 18 drives the guide rod 14 to move upward through the snap ring 8, causing the sealing gasket 12 to leave the oil drain hole 31. At this time, the oil fluid is discharged from the oil drain hole 31, playing the role of a safety valve.

[0034] In other embodiments, the disc spring may not be provided, and a cylindrical helical compression spring may be sleeved outside the guide post.

[0035] In other embodiments, when setting the assembly method of the spring seat and the guide sleeve, an annular groove with the same upper and lower diameters may also be provided at the end of the large-diameter section. At this time, the spring seat is cylindrical and adapted to the annular groove, and the third sealing ring is located between the upper end of the spring seat and the upper groove wall of the groove.

[0036] In other embodiments, when setting the assembly method of the second spring, the spring seat may be provided below the large-diameter section, so that the third sealing ring is clamped between the spring seat and the bottom of the large-diameter section, that is, the spring seat does not extend into the interior of the large-diameter section. At this time, an annular boss is still provided inside the valve body, and the second spring is installed between the annular boss and the spring seat.

[0037] In other embodiments, the spring seat may not be provided. At this time, an annular groove may be provided on the inner wall of the lower end of the large-diameter section, so that the third sealing ring is installed in the annular groove. The third sealing ring is in sealing cooperation with the outer peripheral surface of the piston. At this time, the second spring is no longer provided, and the annular boss is no longer provided inside the valve body.

[0038] In other embodiments, the oil passage holes may not be provided on the guide rod. At this time, the spring seat, the second spring, and the annular boss may not be provided. The third sealing ring may not be provided or may be provided, but the third sealing ring is located on the guide sleeve. An outward-turned edge is provided at the lower end of the piston, and the outward-turned edge is in guiding cooperation with the inner wall of the valve body, so that when in use, the piston has sufficient end face area to push the piston to move upward when the oil fluid is greater than a certain value.

[0039] In other embodiments, a dust-proof ring may not be provided in the inner hole of the guide sleeve.

[0040] In other embodiments, the second annular groove may not be provided on the small-diameter section, but on the cylinder body.

[0041] In other embodiments, the first annular groove may not be provided on the large-diameter section, but on the valve body.

[0042] In other embodiments, the first sealing ring and the second sealing ring may not be provided, nor the second annular groove be provided on the small-diameter section and the first annular groove be provided on the large-diameter section. A sealing ring may be clamped between the end faces of the cylinder body and the valve body.

[0043] Finally, it should be noted that the above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still make modifications to the technical solutions described in the foregoing embodiments without creative efforts, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. Oil pressure monitoring and protection device, characterized in that: It includes a valve body, a cylinder body and a valve seat fixed to the upper and lower parts of the valve body by bolts. A guide sleeve is installed between the valve body and the cylinder body. The valve body has a valve cavity. The valve seat is provided with an oil inlet hole and an oil drain hole communicating with the valve cavity. A push component is installed in the guide sleeve, which is used to block the oil drain hole when the oil pressure in the valve cavity is low and is pushed by the oil to move and open the oil drain hole when the oil pressure is high. A moving part pushed by the push component is installed on the cylinder body. A control switch triggered when the oil pressure reaches a set value is installed on the moving part and / or the cylinder body. The guide sleeve includes a large-diameter section and a small-diameter section. The large-diameter section is located inside the valve body, and the small-diameter section is located inside the cylinder body. The stepped surface between the large-diameter section and the small-diameter section, the end face of the valve body and the end face of the cylinder body are in contact with each other. A step for blocking the end face of the large-diameter section is provided inside the valve body.

2. The oil pressure monitoring and protection device according to claim 1, wherein: A first sealing ring is provided between the outer peripheral surface of the large-diameter section and the inner wall of the valve body.

3. The oil pressure monitoring and protection device according to claim 2, characterized in that: A first annular groove is formed on the outer peripheral surface of the large-diameter section. The first sealing ring is installed in the first annular groove and is in sealing cooperation with the inner wall of the valve body.

4. The oil pressure monitoring and protection device according to any one of claims 1-3, characterized in that: A second sealing ring is provided between the outer peripheral surface of the small-diameter section and the inner wall of the cylinder body.

5. The oil pressure monitoring and protection device according to claim 4, characterized in that: A second annular groove is formed on the outer peripheral surface of the small-diameter section. The second sealing ring is installed in the second annular groove and is in sealing cooperation with the inner wall of the cylinder body.

6. The oil pressure monitoring and protection device according to any one of claims 1 to 3, characterized in that: A dust-proof ring is installed in the inner hole of the guide sleeve, and the dust-proof ring is located at the end of the small-diameter section.

7. The oil pressure monitoring and protection device according to any one of claims 1-3, characterized in that: The push component includes a piston that is in guiding cooperation with the inner hole of the guide sleeve and a guide rod with one end extending into the inner hole of the piston. A sealing pad for blocking the oil drain hole is provided at the other end of the guide rod. A first spring is installed between the end of the guide rod extending into the inner hole of the piston and the bottom of the inner hole of the piston. A communication hole communicating the valve cavity and the inner hole of the piston is provided on the guide rod. A shoulder is provided on the outer periphery of the guide rod. A snap ring is installed at the orifice position of the inner hole of the piston. The snap ring is used to cooperate with the shoulder to block and drive the guide rod to move upward together when the piston moves upward to a certain extent.

8. The oil pressure monitoring and protection device according to claim 7, characterized in that: An annular boss is provided on the inner wall of the valve body. A spring seat is installed at the end of the large-diameter section. One end of the spring seat extends into the inside of the large-diameter section, and a third sealing ring is clamped between the spring seat and the large-diameter section. A second spring is installed between the other end of the spring seat and the annular boss. The third sealing ring is in sealing cooperation with the outer peripheral surface of the piston.

9. The oil pressure monitoring and protection device according to claim 8, characterized in that: A stepped hole is provided in the part of the end of the large-diameter section for the spring seat to extend into. The stepped hole includes a large-diameter hole and a small-diameter hole. The spring seat includes a large-head section and a small-head section. The small-head section extends into the small-diameter hole, and the large-head section extends into the large-diameter hole. The third sealing ring is located in the small-diameter hole.

10. The oil pressure monitoring and protection device according to any one of claims 1-3, characterized in that: A cover plate is installed at one end of the cylinder body away from the valve body. A disc spring is installed between the moving part and the cover plate.

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