A hydraulic control automatic unloading valve for lubricating system

Abstract

The utility model discloses a kind of liquid control automatic unloading valves for lubrication system, belong to centralized lubrication system control technical field, comprising: valve body, it is equipped with at least one oil inlet, at least one oil return and at least two working oil outlet;Reversing valve core assembly, it is set in valve body, including axially movable main plunger;Elastic reset mechanism, for main plunger provides reset elastic force;Mechanical resistance switching mechanism, for when main plunger moves through mid-position, the variable mechanical resistance of opposite direction with the current motion direction of main plunger is generated;Main plunger is periodically reciprocated between first working position and second working position under the action of hydraulic drive force, reset elastic force and variable mechanical resistance.The liquid control automatic unloading valve of the utility model example is self-driven with system pressure, solve the problem that existing electromagnetic unloading valve exists in high viscosity grease application, energy consumption is high, prone to heat, poor reliability, with the advantage that structure is strong in self-adaptability, application form is flexible.

Description

Technical Field

[0001] This utility model relates to the field of centralized lubrication system control technology, and in particular to a hydraulically controlled automatic unloading valve for a lubrication system. Background Technology

[0002] With the development of mechanical equipment technology, centralized lubrication systems, as a key subsystem in equipment operation, have undergone continuous technological evolution. Quantitative distribution lubrication systems are an important branch of centralized lubrication, characterized by the requirement to fully release system pressure at the end of the system's working cycle; therefore, unloading valves are essential. The performance of the unloading valves directly affects the system's reliability, energy efficiency, and maintenance costs.

[0003] In thin oil lubrication systems, the unloading valve has a relatively simple structure, often using an umbrella-shaped rubber valve plate, which utilizes the pressure difference before and after the valve plate to achieve unloading when the system stops. However, in grease lubrication systems, due to the high viscosity of grease, high system pressure, and the fact that oil is usually supplied by a plunger pump, it is impossible to form a self-unloading pressure difference. Therefore, a forced unloading method must be used.

[0004] Currently, most grease lubrication systems use electromagnetic unloading valves to achieve forced unloading. These valves rely on electromagnets to drive the valve core, resulting in a simple structure and convenient control. However, these valves have significant drawbacks: to overcome the resistance caused by high-viscosity grease, high-power electromagnets must be selected, leading to high energy consumption, severe heat generation, and potential coil overheating and damage during prolonged operation, making reliability difficult to guarantee. Furthermore, the power of the electromagnet often exceeds the power of the lubrication pump motor, which is inconsistent with energy-saving trends.

[0005] Therefore, there is an urgent need for an unloading valve solution that requires no external power drive, is suitable for high-viscosity greases, has a reliable structure, and is energy-saving. Utility Model Content

[0006] To address the shortcomings of the existing technology, the purpose of this utility model is to provide a hydraulically controlled automatic unloading valve for lubrication systems. This unloading valve does not require external power to drive it and is self-driven by system pressure. It solves the problems of high energy consumption, easy overheating, and poor reliability of existing electromagnetic unloading valves in the application of high-viscosity greases. At the same time, it has the advantages of strong structural adaptability and flexible application.

[0007] The technical solution adopted by this utility model to solve its technical problem is as follows: A hydraulically controlled automatic unloading valve for a lubrication system is provided, comprising: The valve body is provided with at least one oil inlet, at least one oil return port and at least two working oil outlets; A reversing valve core assembly, disposed within the valve body, includes a main plunger that can move axially within the valve body; The oil circuit feedback control mechanism, whose control logic is based on the axial position of the main plunger, is configured as follows: When the main plunger is in the first working position, the pressure oil in the oil inlet is led to the first end of the main plunger to generate the first hydraulic driving force, and an oil supply passage is established between the oil inlet and the first working oil outlet, while an unloading passage is established between the second working oil outlet and the return oil port. When the main plunger is in the second working position, the pressure oil in the oil inlet is led to the second end of the main plunger to generate a second hydraulic driving force, and an oil supply passage is established between the oil inlet and the second working oil outlet, while an unloading passage is established between the first working oil outlet and the return oil port. An elastic reset mechanism is used to provide a reset elastic force to the main plunger; A mechanical resistance switching mechanism, linked to the main plunger, is used to generate variable mechanical resistance in the opposite direction to the current direction of movement of the main plunger when the main plunger moves through the middle position. The main plunger, under the combined action of hydraulic driving force, reset elastic force and variable mechanical resistance, performs periodic reciprocating motion between the first working position and the second working position, thereby realizing the alternating oil supply and unloading of the at least two working oil outlets.

[0008] Furthermore, the valve body is provided with two oil inlets, and the two oil inlets are interconnected inside the valve body through flow channels.

[0009] Furthermore, one of the oil inlets is externally blocked, so that the valve body presents a single oil inlet to the outside.

[0010] Furthermore, the mechanical resistance switching mechanism includes: A driven member that is linked to the main plunger; A fixed guide component has a guide profile on its inner wall that includes straight segments and oblique segments; A rolling element, which is elastically preloaded, is disposed between the driven member and the guide member; When the rolling element moves to the inclined segment under the drive of the driven member, the elastic preload is converted into axial resistance acting on the driven member, forming a variable mechanical resistance.

[0011] Furthermore, the driven member is a slider, the guide member is a sliding sleeve, the rolling element is a steel ball, the elastic preload is provided by a ball spring, and the inclined segment is an inclined plane at a 45° angle to the axial direction.

[0012] Furthermore, the reversing valve core assembly includes a plunger sleeve fixed to the valve body and a main plunger. The main plunger is slidably disposed in the plunger sleeve, and its cylindrical surface is provided with at least two annular grooves. The annular grooves are connected to the end of the main plunger through an oil passage disposed inside the main plunger, so as to form a feedback path for pressure oil in the oil circuit feedback control mechanism.

[0013] Furthermore, the main plunger controls the connection and isolation between each annular oil groove through the sliding sealing effect of its shoulder and the cooperation of the plunger sleeve. It also establishes or cuts off the connection between the oil inlet, oil return, each working oil outlet, and the oil passage at the end of the main plunger through the relative positional relationship between its annular groove and the radial oil hole on the plunger sleeve, thereby realizing the switching of the oil circuit.

[0014] Furthermore, the elastic reset mechanism includes a pair of main springs acting on both sides of the main plunger axially.

[0015] Furthermore, it also includes a position detection component, which includes a magnet and a reed switch. The magnet is disposed on a magnetic rod that moves synchronously with the main plunger, and the reed switch is fixedly installed in the valve body or pressure plate, and its sensing position corresponds to a specific stroke position of the main plunger.

[0016] A lubrication system includes a lubrication pump, at least one lubrication distributor, and a hydraulically controlled automatic unloading valve; the outlet of the lubrication pump is connected to the inlet of the hydraulically controlled automatic unloading valve, and the working outlet of the hydraulically controlled automatic unloading valve is connected to the lubrication distributor. Compared with the prior art, the beneficial effects of this utility model are as follows: 1. The hydraulic control automatic unloading valve for the lubrication system of this utility model uses the hydraulic pressure of the lubrication system itself as the driving force. Through the conversion of the internal structure, the valve core can achieve automatic reciprocating motion and unloading function. It abandons the high-power electromagnet driving method relied on by traditional electromagnetic unloading valves. The valve does not consume any external power during operation, eliminating the potential faults such as coil overheating and burnout caused by continuous electromagnet power supply. The reliability is fundamentally improved, and the system can also achieve energy-saving operation. 2. The hydraulically controlled automatic unloading valve for the lubrication system in this utility model example has a driving force that comes directly from the system pressure. The magnitude of the driving force is proportional to the system working pressure. Its operating capability is not affected by the viscosity of the lubricating medium. Whether it is low-viscosity thin oil or high-viscosity grease, it can operate reliably, which greatly expands the application field of the product. 3. The hydraulically controlled automatic unloading valve for the lubrication system of this utility model relies on the dynamic balance of hydraulic driving force, elastic restoring force and variable mechanical resistance for automatic reciprocating motion. By simply replacing the main spring and / or ball spring with different stiffness or preload, the valve core's action pressure threshold and dynamic response characteristics can be easily adjusted, thereby forming a series of products that can be adapted to various lubrication systems with different pressure levels and flow requirements. 4. The hydraulically controlled automatic unloading valve for the lubrication system in this utility model example can be installed on the system pipeline as an independent valve block module, which is convenient for the modification and upgrading of the existing system. Alternatively, its core structure can be integrated into the pump body or pump cover of the lubrication pump to form a pump valve unit, which saves installation space, simplifies external pipelines, and improves system integration. 5. The hydraulically controlled automatic unloading valve for the lubrication system in this utility model example can be designed as a dual-way valve with two working oil outlets to provide alternating oil supply and unloading for two sets of lubrication circuits, thereby achieving dual-line lubrication. Alternatively, it can be designed as a single-way valve with only one working oil outlet to meet the unloading requirements of a single-line lubrication system. Attached Figure Description

[0017] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure from another perspective; Figure 3 This is a sectional view; Figure 4 This is a schematic diagram of the left working position state structure; Figure 5 This is a schematic diagram of the right working position state structure; Figure 6 This is a schematic diagram of the midpoint state structure.

[0018] In the diagram: 1-valve body, 2-plunger sleeve, 3-main plunger, 4-slider, 5-sliding sleeve, 6-retaining ring, 7-left pressure plate, 8-right pressure plate, 9-main spring, 10-ball spring, 11-ball support, 12-magnetic rod, 13-magnet, 14-reed switch, 15-steel ball, P-oil inlet, A-first oil outlet, B-second oil outlet, T-oil return port. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the relevant utility model and not intended to limit the scope of the utility model. Furthermore, it should be noted that, for ease of description, only the parts relevant to the utility model are shown in the accompanying drawings.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 1-3 As shown, this embodiment provides a hydraulically controlled automatic unloading valve for a lubrication system, including a valve body 1. The valve body 1 has five external oil ports on its wall: an oil inlet P, a first oil outlet A, a return oil port T, a second oil outlet B, and another oil inlet P. The two oil inlets P are interconnected inside the valve body 1 through channels formed by casting or drilling. In actual installation, one oil inlet P is blocked, so the valve body 1 only presents one oil inlet P, two oil outlets, and one return oil port T to the outside. Five annular oil grooves are machined on the inner wall of the valve body 1, corresponding to and communicating with the five external oil ports.

[0022] The plunger sleeve 2 is a hollow cylindrical component, press-fitted or fixed to the center of the inner bore of the valve body 1 by a retaining ring 6. Multiple O-rings are fitted onto the outer circumference of the plunger sleeve 2 to separate the five annular oil grooves within the valve body 1. Five radial oil holes are machined on the side wall of the plunger sleeve 2 corresponding to the positions of the five annular oil grooves, thereby enabling communication between the internal and external oil passages of the plunger sleeve 2.

[0023] The main plunger 3 is the core moving component of the directional valve assembly, precisely fitting into the inner bore of the plunger sleeve 2. The cylindrical surface of the main plunger 3 has three sections of relatively large-diameter shoulders and two sections of relatively small-diameter annular grooves. The shoulders, in contact with the inner bore of the plunger sleeve 2, serve to provide a sliding seal and isolate the oil chamber. The annular grooves are used to connect different oil passages at specific locations. An end-face oil hole is machined on both the left and right end faces of the main plunger 3. These two end-face oil holes, through axial channels drilled inside the main plunger 3, correspond one-to-one with the radial transverse holes at the bottom of the annular grooves at both ends. This design forms the physical basis of the oil circuit feedback control: system pressure can be guided to the corresponding end face of the main plunger 3 through the currently connected end-face oil holes, generating hydraulic pressure to drive its axial movement.

[0024] Left pressure plate 7 and right pressure plate 8 are fixed to the left and right sides of valve body 1 respectively by screws, forming a closed mounting cavity together with valve body 1. The motion auxiliary mechanisms on both sides are the same. Taking the right side as an example, the right end face of the main plunger 3 abuts against the left end face of the slider 4. The slider 4, as the driven member, has a main spring 9 installed at its right end, and the other end of the main spring 9 abuts against the pressure plate on the right side. The middle part of the slider 4 is fitted into the inner hole of the sliding sleeve 5 and can slide axially. The sliding sleeve 5, as a fixed guide member, is axially limited by the retaining ring 6 and pressed against the end face of the plunger sleeve 2. Finally, it is fixed to valve body 1 by screws by the pressure plate on the right side. The inner hole profile of the sliding sleeve 5 is composed of a straight line segment and a 45° inclined line segment.

[0025] The slider 4 has an internal mounting cavity containing a ball spring 10, two ball supports 11, and two steel balls 15. The ball spring 10 is compressed, and its elastic force pushes the two steel balls 15 radially outward through the two ball supports 11, ensuring they remain firmly against the inner wall of the sliding sleeve 5. When the steel balls 15 are in the straight section of the inner hole of the sliding sleeve 5, the slider 4 can slide freely. When the steel balls 15 move to the 45° inclined section, the radial force of the ball spring 10, through the interaction between the steel balls 15 and the inclined surface, is converted into an axial resistance that hinders the slider 4 from moving forward. This resistance is the variable mechanical resistance, which intervenes when the main plunger 3 passes the neutral position, playing a crucial role in switching its dynamic balance.

[0026] The right pressure plate 8 also houses a position detection assembly, including a magnetic rod 12, a magnet 13, and a reed switch 14. The magnetic rod 12 contacts or connects to the slider 4 or the main plunger 3, and can move synchronously with it. The magnet 13 is embedded in the magnetic rod 12. The reed switch 14 is fixed at a specific position on the right pressure plate 8, and its sensing point corresponds to the position of the magnet 13 when the main plunger 3 moves to the right working position (or the left working position, depending on design requirements). When the magnet 13 approaches, the contacts inside the reed switch 14 close, outputting a switching signal.

[0027] Working principle: Under the dynamic balance of the system's hydraulic driving force, the reset elastic force of the two main springs 9, and the variable mechanical resistance generated by the steel ball 15-inclined surface mechanism, the main plunger 3 achieves periodic automatic reciprocating motion, and then systematically switches the connection relationship between the four oil ports P, A, B, and T by changing the position of its shoulder and groove.

[0028] like Figure 4 As shown, in the initial state (assuming the main plunger 3 is in the left working position): PA supplies oil, BT unloads. Oil supply path: Pressure oil at inlet P - oil hole on the left side of plunger sleeve 2 - fills the annular groove on the left end of main plunger 3 - splits into two paths. The first path goes to the first outlet A and supplies oil to the lubrication point; the second path enters the left end chamber of main plunger 3 through the oil hole on the left end face.

[0029] Unloading path: Second oil outlet B - corresponding oil hole of plunger sleeve 2 - annular groove at the right end of main plunger 3 - oil hole at the right end face of main plunger 3 - its right end chamber - oil hole at the return oil port T on plunger sleeve 2 - oil tank.

[0030] Sealing point: The intermediate shoulder of the main plunger 3 blocks the oil hole on the plunger sleeve 2 that directly connects the P port and the T port.

[0031] Force and balance: The oil pressure in the left end chamber generates a hydraulic thrust to the right. In the right mechanism, the steel ball 15 is in the inclined section, generating an axial resistance to the left. Both the left and right main springs 9 are compressed, generating forces to the right and left respectively, and the valve core is stable in the left position.

[0032] When pipe A is filled, the pressure increases, the balance is broken, and the main plunger 3 begins to move to the right. When it reaches the neutral position, both ports P and T are closed by the shoulder of the main plunger 3. Ports A and B are only connected to the left and right chambers of the main plunger 3 through internal oil passages. The right-side steel ball 15 slides into the straight hole from the inclined plane, while the left-side steel ball 15 begins to enter the inclined plane, generating resistance to the right. The forces of the left and right main springs 9 are basically balanced. Using inertia and the residual pressure on the left side, the main plunger 3 overcomes the slight resistance and continues to move to the right past the neutral position.

[0033] like Figure 5 As shown, when the main plunger 3 is in the right working position, PB supplies oil and AT unloads.

[0034] Oil supply path: Pressure oil at port P - oil hole on the right side of plunger sleeve 2 - fills the annular groove on the right end of main plunger 3 - splits into two paths. The first path supplies oil to the second oil outlet B, and the second path enters the right end chamber of main plunger 3 through the oil hole on the right end face of main plunger 3.

[0035] Unloading path: First oil outlet A - corresponding oil hole of plunger sleeve 2 - annular groove at the left end of main plunger 3 - oil hole at the left end face of main plunger 3 - left end chamber - oil hole at T-port on plunger sleeve 2 - oil tank.

[0036] The hydraulic pressure in the right chamber generates a hydraulic thrust to the left, while in the left mechanism, steel ball 15, positioned on the inclined section, generates axial resistance to the right. Due to the low initial pressure in the B-port pipeline, the main plunger 3 continues to move to the right working position under inertia. Once the pressure at the B-port is established, it stores power for the next leftward movement.

[0037] When the pressure in the B-port pipeline reaches a set value sufficient to break the current balance, the main plunger 3 begins to move to the left, a process completely symmetrical to the rightward movement described above. This cycle repeats continuously, achieving automatic, periodic alternating oil supply and unloading between ports A and B.

[0038] like Figure 6 As shown, when the main plunger 3 is in the neutral position, both the oil inlet P and the oil return T are blocked by the shaft shoulder. The first oil outlet A is connected to the left end chamber of the main plunger 3, and the second oil outlet B is connected to the right end chamber of the main plunger 3. At this time, the left and right ends of the main plunger 3 are not affected by the hydraulic pressure of the lubrication pump outlet.

[0039] Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by specific combinations of the above-mentioned technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-mentioned technical features or their equivalent features without departing from the inventive concept. For example, technical solutions formed by substituting the above-mentioned features with technical features disclosed in this application (but not limited to) that have similar functions.

Claims

1. A hydraulically controlled automatic unloading valve for a lubrication system, characterized in that, include: The valve body (1) is provided with at least one oil inlet (P), at least one oil return (T) and at least two working oil outlets; A reversing valve core assembly, which is disposed within the valve body (1), includes a main plunger (3) that can move axially within the valve body (1). The oil circuit feedback control mechanism, whose control logic is based on the axial position of the main plunger (3), is configured as follows: When the main plunger (3) is in the first working position, the pressure oil in the oil inlet (P) is led to the first end of the main plunger (3) to generate the first hydraulic driving force, and an oil supply passage is established between the oil inlet (P) and the first working oil outlet, while an unloading passage is established between the second working oil outlet and the return oil port (T). When the main plunger (3) is in the second working position, the pressure oil in the oil inlet (P) is led to the second end of the main plunger (3) to generate the second hydraulic driving force, and an oil supply passage is established between the oil inlet (P) and the second working oil outlet, while an unloading passage is established between the first working oil outlet and the return oil port (T). An elastic reset mechanism is used to provide a reset elastic force for the main plunger (3); The mechanical resistance switching mechanism is linked with the main plunger (3) and is used to generate a variable mechanical resistance in the opposite direction to the current movement direction of the main plunger (3) when the main plunger (3) moves through the middle position. The main plunger (3) reciprocates periodically between the first working position and the second working position under the combined action of hydraulic driving force, reset elastic force and variable mechanical resistance, so as to realize the alternating oil supply and unloading of the at least two working oil outlets.

2. The hydraulically controlled automatic unloading valve for a lubrication system according to claim 1, characterized in that, The valve body (1) is provided with two oil inlets (P), and the two oil inlets (P) are interconnected inside the valve body (1) through a flow channel.

3. The hydraulically controlled automatic unloading valve for a lubrication system according to claim 2, characterized in that, One of the oil inlets (P) is blocked externally, so that the valve body (1) presents a single oil inlet to the outside.

4. The hydraulically controlled automatic unloading valve for a lubrication system according to claim 1, characterized in that, The mechanical resistance switching mechanism includes: A driven member that is linked to the main plunger (3); A fixed guide component has a guide profile on its inner wall that includes straight segments and oblique segments; A rolling element, which is elastically preloaded, is disposed between the driven member and the guide member; When the rolling element moves to the inclined segment under the drive of the driven member, the elastic preload is converted into axial resistance acting on the driven member, forming a variable mechanical resistance.

5. A hydraulically controlled automatic unloading valve for a lubrication system according to claim 4, characterized in that, The driven member is a slider (4), the guide member is a sliding sleeve (5), the rolling element is a steel ball (15), the elastic preload is provided by a ball spring (10), and the inclined segment is an inclined plane at a 45° angle to the axial direction.

6. A hydraulically controlled automatic unloading valve for a lubrication system according to claim 1, characterized in that, The reversing valve core assembly includes a plunger sleeve (2) fixed inside the valve body (1) and a main plunger (3); the main plunger (3) is slidably disposed inside the plunger sleeve (2), and at least two annular grooves are provided on its cylindrical surface. The annular grooves are connected to the end of the main plunger (3) through an oil passage disposed inside the main plunger (3) to form a feedback path for pressure oil in the oil circuit feedback control mechanism.

7. A hydraulically controlled automatic unloading valve for a lubrication system according to claim 6, characterized in that, The main plunger (3) controls the connection and isolation between each annular oil groove through the sliding sealing action of its shoulder and the cooperation of the plunger sleeve (2). It also establishes or cuts off the connection between the oil inlet (P), the oil return port (T) and each working oil outlet and the oil passage at the end of the main plunger (3) through the relative positional relationship between its annular groove and the radial oil hole on the plunger sleeve (2), thereby realizing the switching of the oil circuit.

8. A hydraulically controlled automatic unloading valve for a lubrication system according to claim 1, characterized in that, The elastic reset mechanism includes a pair of main springs (9) that act on both sides of the main plunger (3) axially.

9. A hydraulically controlled automatic unloading valve for a lubrication system according to any one of claims 1-8, characterized in that, It also includes a position detection component, which includes a magnet (13) and a reed switch (14). The magnet (13) is disposed on a magnetic rod (12) that moves synchronously with the main plunger (3). The reed switch (14) is fixedly installed in the valve body (1) or pressure plate, and its sensing position corresponds to a specific stroke position of the main plunger (3).

10. A lubrication system, characterized in that, It includes a lubrication pump, at least one lubrication distributor, and a hydraulically controlled automatic unloading valve as described in any one of claims 1-9; the outlet of the lubrication pump is connected to the inlet (P) of the hydraulically controlled automatic unloading valve, and the working outlet of the hydraulically controlled automatic unloading valve is connected to the lubrication distributor.

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