Plunger pair, pump head assembly and lubricating pump

Abstract

The utility model relates to a plunger pair, a pump head assembly and a lubricating pump. The valve body is provided with a valve cavity, a grease inlet and a grease outlet are formed in the valve body, and a sealing surface with an outward opening is arranged at the grease outlet; the plunger is assembled in the valve cavity in a sliding manner; the one-way valve comprises a reset spring and a sealing structure for blocking the grease outlet, the sealing structure comprises a valve element arranged at the grease outlet of the valve cavity, one end of the valve element is matched with the reset spring in an abutting mode, the other end of the valve element abuts against the sealing face through a matching face, and the reset spring provides elastic force for the valve element towards the extrusion sealing face. A pushing table extending in the axial direction is arranged at the end, close to the plunger, of the valve element so as to reduce an air storage gap between the front end face of the pushing table and the front end face of the plunger, at least one groove is formed in the peripheral face of the pushing table and extends to the matching face from the front end face of the pushing table, and an oil passing channel is defined by the groove and the cavity wall of the valve cavity. When being extruded by the plunger, the lubricating grease can flow out between the matching surface and the sealing surface through the oil passing channel. The plunger pump has the advantages of difficulty in evacuating the plunger and low failure rate.

Description

Technical Field

[0001] The utility model relates to a plunger pair, a pump head assembly and a lubrication pump. Background Art

[0002] In the field of dry oil lubrication, the lubrication pump is a key component of the centralized lubrication system, mainly including a pump head assembly 1 and an oil tank, such as Figure 1 , 2 As shown, the pump head assembly 1 is provided with a motor 11, a transmission mechanism 12, an eccentric wheel mechanism 13, a plunger pair 14, etc. The plunger pair 14 includes a valve body 141, a plunger 142, and a one-way valve 143 provided at a grease outlet 1412 of the valve. During operation, the eccentric wheel mechanism 12 is driven to rotate by the motor 11, thereby driving the plunger 142 of each plunger pair 14 to perform linear reciprocating motion in its valve body 141, so that the grease near the grease inlet 1411 of the valve body 141 is drawn into the valve body 141 and discharged after passing through the one-way valve 143 at the grease outlet 1412, thereby achieving the purpose of pumping grease to the friction pair.

[0003] During the use of the lubrication pump, due to the viscosity of the grease, low temperature and bubbles mixed in the grease, the plunger pair often has a vacuum failure, that is, the grease sucked by the plunger pair is not enough to open the one-way valve, and the grease cannot be pumped out normally, eventually leading to a failure of the lubrication pump. Utility Model Content

[0004] The purpose of the utility model is to provide a plunger pair to solve the technical problem of evacuating the plunger pair. The purpose of the utility model is also to provide a pump head assembly and a lubrication pump using the plunger pair.

[0005] The technical solution of the plunger pair of the utility model is as follows: the plunger pair comprises:

[0006] The valve body has a valve cavity, and is provided with a grease inlet and a grease outlet communicating with the valve cavity, and a sealing surface opening outward is provided at the grease outlet;

[0007] A plunger is slidably assembled in the valve cavity;

[0008] A one-way valve, comprising a return spring and a sealing structure for blocking the grease outlet, the sealing structure comprising a valve core arranged at the grease outlet of the valve cavity, one end of the valve core being abutted against the return spring, and the other end being abutted against the sealing surface through a matching surface, the return spring providing the valve core with an elastic force to press the sealing surface;

[0009] An axially extending push platform is provided at one end of the valve core close to the plunger to reduce the air gap between the front end face of the push platform and the front end face of the plunger. At least one groove is provided on the outer peripheral surface of the push platform. The groove extends from the front end face of the push platform to the mating surface. The groove and the cavity wall of the valve cavity form an oil passage. When the grease is squeezed by the plunger, it can flow out from between the mating surface and the sealing surface through the oil passage.

[0010] The beneficial effects of the present solution are as follows: relative to the prior art, when the plunger of the present application moves from the oil suction limit position to the oil discharge limit position, the grease entering from the grease inlet can be pushed toward the grease outlet and the one-way valve can be opened. Even if the grease contains bubbles, since the front end face of the plunger is close to or in contact with the front end face of the push platform of the valve core when the plunger moves to the oil discharge limit position, the amount of gas stored between the two can be reduced. Therefore, when the plunger returns to move toward the oil suction limit position, the vacuum suction force of the plunger pair will not be affected by the small amount of gas between the front end face of the plunger and the front end face of the push platform of the valve core, that is, the normal suction capacity of the plunger pair will not be affected, so the plunger is not easy to be evacuated. At the same time, the gap between the front end face of the plunger and the front end face of the push platform of the valve core is very small, so the gas between the two will also be discharged, that is, the situation where the one-way valve cannot be opened when the plunger pushes the gas to compress will not occur. The above two points ensure that the plunger pair can work normally and there will be no evacuation failure. The setting of the groove can ensure that the cross-section of the grease oil passage is large enough while the plunger is not emptied. This is because if the gap between the outer peripheral surface of the push platform and the wall of the valve chamber is to be as small as possible (the less gas stored, the less gas stored, the greater the suction force when the plunger sucks in the next stroke, that is, the stored gas will affect the vacuum suction force of the plunger), the diameter of the push platform needs to be as large as possible. Under the premise of the same cross-sectional area of ​​the flow channel, the setting of the groove can make the grease flow cross-sectional area wider. The wider the cross-sectional area, the smaller the impact on the grease flow resistance. For example, a square (4*4) channel with a cross-sectional area of ​​16 has less impact on the grease flow resistance than a rectangular (1*16) channel with a cross-sectional area of ​​16.

[0011] Furthermore, the sealing surface and the matching surface are conical, thereby having an auxiliary positioning function.

[0012] Furthermore, the cross section of the groove is C-shaped, rectangular or arc-shaped.

[0013] Furthermore, there are a plurality of grooves, and the grooves are evenly distributed along the circumference of the push platform.

[0014] Furthermore, the cross section of the valve cavity is circular, the cross section of the pushing platform is polygonal, and the side surface of the pushing platform and the cavity wall of the valve cavity form a plurality of oil passages.

[0015] Furthermore, a valve stem is coaxially arranged on one side of the positioning cone surface close to the return spring, and the return spring is sleeved on the valve stem.

[0016] Furthermore, an annular groove is provided on one side of the positioning cone surface close to the return spring, and the return spring is inserted into the annular groove.

[0017] Furthermore, a guide platform is provided on one side of the valve core close to the return spring, the cross section of the valve cavity is circular, the maximum outer diameter of the guide platform is consistent with the inner diameter of the valve cavity, so that the two can be guided and slidably matched, and an oil groove for grease to pass through is also provided on the outer peripheral surface of the guide platform. The setting of the guide platform and the oil groove on its surface ensures that the valve core can be positioned very conveniently and accurately, and ensures that the grease can be discharged normally.

[0018] The technical scheme of the pump head assembly of the utility model is as follows: the pump head assembly includes a motor, an eccentric wheel mechanism driven by the motor, and a plunger pair driven by the eccentric wheel mechanism, and the plunger pair includes:

[0019] The valve body has a valve cavity, and is provided with a grease inlet and a grease outlet communicating with the valve cavity, and a sealing surface opening outward is provided at the grease outlet;

[0020] A plunger is slidably assembled in the valve cavity;

[0021] A one-way valve, comprising a return spring and a sealing structure for blocking the grease outlet, the sealing structure comprising a valve core arranged at the grease outlet of the valve cavity, one end of the valve core being abutted against the return spring, and the other end being abutted against the sealing surface through a matching surface, the return spring providing the valve core with an elastic force to press the sealing surface;

[0022] An axially extending push platform is provided at one end of the valve core close to the plunger to reduce the air gap between the front end face of the push platform and the front end face of the plunger. At least one groove is provided on the outer peripheral surface of the push platform. The groove extends from the front end face of the push platform to the mating surface. The groove and the cavity wall of the valve cavity form an oil passage. When the grease is squeezed by the plunger, it can flow out from between the mating surface and the sealing surface through the oil passage.

[0023] The beneficial effects of the present solution are as follows: relative to the prior art, when the plunger of the present application moves from the oil suction limit position to the oil discharge limit position, the grease entering from the grease inlet can be pushed toward the grease outlet and the one-way valve can be opened. Even if the grease contains bubbles, since the front end face of the plunger is close to or in contact with the front end face of the push platform of the valve core when the plunger moves to the oil discharge limit position, the amount of gas stored between the two can be reduced. Therefore, when the plunger returns to move toward the oil suction limit position, the vacuum suction force of the plunger pair will not be affected by the small amount of gas between the front end face of the plunger and the front end face of the push platform of the valve core, that is, the normal suction capacity of the plunger pair will not be affected, so the plunger is not easy to be evacuated. At the same time, the gap between the front end face of the plunger and the front end face of the push platform of the valve core is very small, so the gas between the two will also be discharged, that is, the situation where the one-way valve cannot be opened when the plunger pushes the gas to compress will not occur. The above two points ensure that the plunger pair can work normally and there will be no evacuation failure. The setting of the groove can ensure that the cross-section of the grease oil passage is large enough while the plunger is not emptied. This is because if the gap between the outer peripheral surface of the push platform and the wall of the valve chamber is to be as small as possible (the less gas stored, the less gas stored, the greater the suction force when the plunger sucks in the next stroke, that is, the stored gas will affect the vacuum suction force of the plunger), the diameter of the push platform needs to be as large as possible. Under the premise of the same cross-sectional area of ​​the flow channel, the setting of the groove can make the grease flow cross-sectional area wider. The wider the cross-sectional area, the smaller the impact on the grease flow resistance. For example, a square (4*4) channel with a cross-sectional area of ​​16 has less impact on the grease flow resistance than a rectangular (1*16) channel with a cross-sectional area of ​​16.

[0024] Furthermore, the sealing surface and the matching surface are conical, thereby having an auxiliary positioning function.

[0025] Furthermore, the cross section of the groove is C-shaped, rectangular or arc-shaped.

[0026] Furthermore, there are a plurality of grooves, and the grooves are evenly distributed along the circumference of the push platform.

[0027] Furthermore, the cross section of the valve cavity is circular, the cross section of the pushing platform is polygonal, and the side surface of the pushing platform and the cavity wall of the valve cavity form a plurality of oil passages.

[0028] Furthermore, a valve stem is coaxially arranged on one side of the positioning cone surface close to the return spring, and the return spring is sleeved on the valve stem.

[0029] Furthermore, an annular groove is provided on one side of the positioning cone surface close to the return spring, and the return spring is inserted into the annular groove.

[0030] Furthermore, a guide platform is provided on one side of the valve core close to the return spring, the cross section of the valve cavity is circular, the maximum outer diameter of the guide platform is consistent with the inner diameter of the valve cavity, so that the two can be guided and slidably matched, and an oil groove for grease to pass through is also provided on the outer peripheral surface of the guide platform. The setting of the guide platform and the oil groove on its surface ensures that the valve core can be positioned very conveniently and accurately, and ensures that the grease can be discharged normally.

[0031] Furthermore, at least one radially extending stirring and cutting rod is installed on the eccentric wheel mechanism. The stirring and cutting rod can pass through the grease inlet when rotating with the eccentric wheel mechanism, and is used to stir the grease, cut bubbles in the grease, and apply the grease into the grease inlet.

[0032] The beneficial effects of this solution are as follows: a stirring and cutting rod is provided to cut large bubbles in the grease into small bubbles before the grease enters the grease inlet of the plunger pair, thereby avoiding excessive gas entering the plunger pair at one time and causing the plunger pair to be emptied, that is, the less gas entering the plunger pair, the smaller the negative impact of the gas on the vacuum suction of the plunger pair; at the same time, it also has the function of stirring the grease to make the base oil of the grease and the thickener mixed more evenly and to smear the grease into the grease inlet, so that the plunger pair can draw in the grease with a smaller suction force when sucking, because the grease is most easily sucked away by the vacuum suction generated by the plunger pair when it enters the grease inlet.

[0033] Furthermore, during one cycle of movement of the plunger in the valve chamber, the plunger has a first valve position for blocking the fat inlet and a second valve position for reopening the fat inlet. The farthest position of the plunger when moving toward the one-way valve is defined as the minimum eccentric position of the eccentric wheel mechanism. At the minimum eccentric position, the stirring and cutting rod and the plunger have a certain angle, and the angle is set so that when the plunger is between the first valve position and the second valve position, the stirring and cutting rod passes through the fat inlet.

[0034] The beneficial effects of this solution are as follows: setting the stirring and cutting rod within a certain angle range with the plunger at the minimum eccentric position can ensure that the grease is applied to the grease inlet by the stirring and cutting rod before the grease inlet is opened, so that when the grease inlet is opened, the vacuum suction of the plunger can directly suck away the grease that has been applied to the grease inlet. More importantly, when the grease inlet is opened, the vacuum suction of the plunger will suck out a cavity in the grease inlet and a certain area above the grease inlet. If the stirring and cutting rod applies grease to the grease inlet again at this time, the air in the cavity will inevitably be wrapped in the grease, which will easily lead to vacuum during the next suction due to this part of the entrained air. Therefore, the setting position of the stirring and cutting rod is very critical. It is best to make the stirring and cutting rod apply grease to the grease inlet before the grease inlet is opened to avoid the above situation.

[0035] The technical solution of the lubrication pump of the utility model is as follows: the lubrication pump comprises a pump head assembly and an oil tank for storing grease, the oil tank is connected to a grease inlet of a plunger pair in the pump head assembly;

[0036] The pump head assembly includes a motor, an eccentric wheel mechanism driven by the motor, and a plunger pair driven by the eccentric wheel mechanism. The plunger pair includes:

[0037] The valve body has a valve cavity, and is provided with a grease inlet and a grease outlet communicating with the valve cavity, and a sealing surface opening outward is provided at the grease outlet;

[0038] A plunger is slidably assembled in the valve cavity;

[0039] A one-way valve, comprising a return spring and a sealing structure for blocking the grease outlet, the sealing structure comprising a valve core arranged at the grease outlet of the valve cavity, one end of the valve core being abutted against the return spring, and the other end being abutted against the sealing surface through a matching surface, the return spring providing the valve core with an elastic force to press the sealing surface;

[0040] An axially extending push platform is provided at one end of the valve core close to the plunger to reduce the air gap between the front end face of the push platform and the front end face of the plunger. At least one groove is provided on the outer peripheral surface of the push platform. The groove extends from the front end face of the push platform to the mating surface. The groove and the cavity wall of the valve cavity form an oil passage. When the grease is squeezed by the plunger, it can flow out from between the mating surface and the sealing surface through the oil passage.

[0041] The beneficial effects of the present solution are as follows: relative to the prior art, when the plunger of the present application moves from the oil suction limit position to the oil discharge limit position, the grease entering from the grease inlet can be pushed toward the grease outlet and the one-way valve can be opened. Even if the grease contains bubbles, since the front end face of the plunger is close to or in contact with the front end face of the push platform of the valve core when the plunger moves to the oil discharge limit position, the amount of gas stored between the two can be reduced. Therefore, when the plunger returns to move toward the oil suction limit position, the vacuum suction force of the plunger pair will not be affected by the small amount of gas between the front end face of the plunger and the front end face of the push platform of the valve core, that is, the normal suction capacity of the plunger pair will not be affected, so the plunger is not easy to be evacuated. At the same time, the gap between the front end face of the plunger and the front end face of the push platform of the valve core is very small, so the gas between the two will also be discharged, that is, the situation where the one-way valve cannot be opened when the plunger pushes the gas to compress will not occur. The above two points ensure that the plunger pair can work normally and there will be no evacuation failure. The setting of the groove can ensure that the cross-section of the grease oil passage is large enough while the plunger is not emptied. This is because if the gap between the outer peripheral surface of the push platform and the wall of the valve chamber is to be as small as possible (the less gas stored, the less gas stored, the greater the suction force when the plunger sucks in the next stroke, that is, the stored gas will affect the vacuum suction force of the plunger), the diameter of the push platform needs to be as large as possible. Under the premise of the same cross-sectional area of ​​the flow channel, the setting of the groove can make the grease flow cross-sectional area wider. The wider the cross-sectional area, the smaller the impact on the grease flow resistance. For example, a square (4*4) channel with a cross-sectional area of ​​16 has less impact on the grease flow resistance than a rectangular (1*16) channel with a cross-sectional area of ​​16.

[0042] Furthermore, the sealing surface and the matching surface are conical, thereby having an auxiliary positioning function.

[0043] Furthermore, the cross section of the groove is C-shaped, rectangular or arc-shaped.

[0044] Furthermore, there are a plurality of grooves, and the grooves are evenly distributed along the circumference of the push platform.

[0045] Furthermore, the cross section of the valve cavity is circular, the cross section of the pushing platform is polygonal, and the side surface of the pushing platform and the cavity wall of the valve cavity form a plurality of oil passages.

[0046] Furthermore, a valve stem is coaxially arranged on one side of the positioning cone surface close to the return spring, and the return spring is sleeved on the valve stem.

[0047] Furthermore, an annular groove is provided on one side of the positioning cone surface close to the return spring, and the return spring is inserted into the annular groove.

[0048] Furthermore, a guide platform is provided on one side of the valve core close to the return spring, the cross section of the valve cavity is circular, the maximum outer diameter of the guide platform is consistent with the inner diameter of the valve cavity, so that the two can be guided and slidably matched, and an oil groove for grease to pass through is also provided on the outer peripheral surface of the guide platform. The setting of the guide platform and the oil groove on its surface ensures that the valve core can be positioned very conveniently and accurately, and ensures that the grease can be discharged normally.

[0049] Furthermore, at least one radially extending stirring and cutting rod is installed on the eccentric wheel mechanism. The stirring and cutting rod can pass through the grease inlet when rotating with the eccentric wheel mechanism, and is used to stir the grease, cut bubbles in the grease, and apply the grease into the grease inlet.

[0050] The beneficial effects of this solution are as follows: a stirring and cutting rod is provided to cut large bubbles in the grease into small bubbles before the grease enters the grease inlet of the plunger pair, thereby avoiding excessive gas entering the plunger pair at one time and causing the plunger pair to be emptied, that is, the less gas entering the plunger pair, the smaller the negative impact of the gas on the vacuum suction of the plunger pair; at the same time, it also has the function of stirring the grease to make the base oil of the grease and the thickener mixed more evenly and to smear the grease into the grease inlet, so that the plunger pair can draw in the grease with a smaller suction force when sucking, because the grease is most easily sucked away by the vacuum suction generated by the plunger pair when it enters the grease inlet.

[0051] Furthermore, during one cycle of movement of the plunger in the valve chamber, the plunger has a first valve position for blocking the fat inlet and a second valve position for reopening the fat inlet. The farthest position of the plunger when moving toward the one-way valve is defined as the minimum eccentric position of the eccentric wheel mechanism. At the minimum eccentric position, the stirring and cutting rod and the plunger have a certain angle, and the angle is set so that when the plunger is between the first valve position and the second valve position, the stirring and cutting rod passes through the fat inlet.

[0052] The beneficial effects of this solution are as follows: setting the stirring and cutting rod within a certain angle range with the plunger at the minimum eccentric position can ensure that the grease is applied to the grease inlet by the stirring and cutting rod before the grease inlet is opened, so that when the grease inlet is opened, the vacuum suction of the plunger can directly suck away the grease that has been applied to the grease inlet. More importantly, when the grease inlet is opened, the vacuum suction of the plunger will suck out a cavity in the grease inlet and a certain area above the grease inlet. If the stirring and cutting rod applies grease to the grease inlet again at this time, the air in the cavity will inevitably be wrapped in the grease, which will easily lead to vacuum during the next suction due to this part of the entrained air. Therefore, the setting position of the stirring and cutting rod is very critical. It is best to make the stirring and cutting rod apply grease to the grease inlet before the grease inlet is opened to avoid the above situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1It is a schematic diagram of the internal structure of a pump head assembly in the prior art;

[0054] Figure 2 for Figure 1 Schematic diagram of the internal structure of the plunger pair;

[0055] Figure 3 It is a structural schematic diagram of an embodiment of a pump head assembly of the utility model;

[0056] Figure 4 for Figure 3 Schematic diagram of the internal structure of the plunger pair;

[0057] Figure 5 for Figure 4 Schematic diagram of the corresponding state of the plunger being at the oil discharge limit position;

[0058] Figure 6 A schematic diagram of the internal structure of the plunger pair (showing the spring seat and return spring, but not the sealing gasket);

[0059] Figure 7 for Figure 6 The cross-sectional view of the plunger pair at the push platform;

[0060] Figure 8 is a perspective view of another embodiment of a plunger;

[0061] Figure 9-11 The figures are cross-sectional views of the push platform of three other embodiments of the plunger pair;

[0062] Figure 12-14 Schematic diagrams of the internal structures of three other embodiments of the plunger pair;

[0063] Fig.15 A schematic diagram of the core structure of another embodiment of a pump head assembly;

[0064] In the figure: 1-pump head assembly, 11-motor, 12-transmission mechanism, 13-eccentric wheel mechanism, 14-plunger pair, 141-valve body, 1411-grease inlet, 1412-grease outlet, 1413-valve chamber, 1414-conical sealing surface, 142-plunger, 143-check valve, 1432-valve stem, 1433-positioning cone, 1435-push platform, 1436-groove, 1437-reset spring, 1438-annular groove, 1439-guide platform, 15-stirring and cutting rod, 16-oil groove, 17-sealing pad, 18-socket structure. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model, that is, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0066] Therefore, the following detailed description of the embodiments of the utility model provided in the accompanying drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents selected embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0067] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0068] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0069] An embodiment of the pump head assembly of the utility model: Figure 3-7As shown, the pump head assembly 1 includes a motor 11, an eccentric wheel mechanism driven by the motor 11, and at least one plunger pair 14 driven by the eccentric wheel mechanism. Among them, the structures of the motor 11, the transmission mechanism 12, the eccentric wheel mechanism 13, the valve body 141 of the plunger pair 14, the plunger 142, the grease inlet 1411, and the grease outlet 1412 are prior art and will not be repeated. It is only necessary to know that the valve body 141 of the plunger pair 14 has a valve cavity 1413, and the valve body 141 is provided with a grease inlet 1411 and a grease outlet 1412 connected to the valve cavity 1413, and a conical sealing surface 1414 opening outward is provided at the grease outlet 1412. In other embodiments, it can also be replaced by other sealing surfaces, such as a plane, and the corresponding positioning cone surface (i.e., the mating surface) is also replaced by a plane. The plunger 142 is slidably assembled in the valve cavity 1413, and has an oil suction limit position and an oil discharge limit position within its active stroke.

[0070] The one-way valve 143 includes a valve core, a sealing gasket 17 and a return spring 1437. The valve core and the sealing gasket constitute a sealing structure for blocking the grease outlet. The valve core is arranged at the grease outlet. The valve core includes a positioning cone 1433. The return spring 1437 provides an elastic force for the sealing gasket 17 and the positioning cone 1433 to press the conical sealing surface 1414. The sealing gasket 17 in this embodiment is a valve stem gasket, that is, one end of the valve core is pressed against the return spring, and the other end is pressed against the conical sealing surface (i.e., the sealing surface) through the positioning cone (i.e., the fitting surface). The other end of the return spring is pressed against the spring seat, and the spring seat is rotated on the valve body through a thread. The return spring provides an elastic force for the valve core to press the conical sealing surface. Figure 4As shown, an axially extending push platform 1435 is provided at one end of the positioning cone surface (i.e., matching surface) 1433 of the valve core away from the reset spring 1437. In this embodiment, the push platform 1435 is cylindrical. When the positioning cone surface 1433 and the conical sealing surface 1414 are pressed against each other, the front end surface of the push platform 1435 contacts or approaches the front end surface of the plunger 142 at the oil discharge limit position, so as to reduce the air gap between the front end surface of the push platform 1435 and the front end surface of the plunger 142. For example, when the positioning cone surface 1433 and the conical sealing surface 1414 are pressed against each other, the distance between the front end surface of the push platform 1435 and the front end surface of the plunger 142 at the oil discharge limit position is 1 mm. Alternatively, the plunger 142 has already been in contact with the front end face of the valve core before reaching the oil discharge limit position. As the plunger continues to move toward the oil discharge limit position, the valve core of the one-way valve is continued to be pushed by the plunger against the push platform, and the positioning cone and the conical sealing surface gradually separate, that is, before the plunger reaches the oil discharge limit position, the one-way valve is always in an open state, and this structure is also within the protection scope of the present application. Compared with the prior art, when the plunger 142 of the present application moves from the oil suction limit position to the oil discharge limit position, the grease entering from the grease inlet 1411 can be pushed toward the grease outlet 1412 and the one-way valve 143 is opened. Even if there are bubbles in the grease, since when the plunger 142 moves to the oil discharge limit position, the front end face of the plunger 142 is close to or in contact with the front end face of the push platform 1435 of the valve core, it is impossible for gas to be stored between the two. Therefore, when the plunger 142 returns to move toward the oil suction limit position, it will not be due to the front end face of the plunger 142. A small amount of gas between the end face and the front end face of the push platform 1435 of the valve core will not affect the vacuum suction of the plunger pair 14, that is, it will not affect the normal suction ability of the plunger pair 14, so the plunger 142 is not easy to be evacuated. At the same time, the gap between the front end face of the plunger 142 and the front end face of the push platform 1435 of the valve core is very small, so the gas between the two will also be discharged, that is, the situation that the one-way valve 143 cannot be opened when the plunger 142 pushes the gas to compress will not occur. The above two points ensure that the plunger pair 14 can work normally and there will be no vacuum failure.

[0071] In this embodiment, four rectangular grooves 1436 are arranged on the outer circumferential surface of the push platform 1435. The four grooves 1436 are evenly distributed along the circumferential direction. The starting point of the groove is the front end surface of the push platform, and the end point of the groove is the contact point between the positioning cone surface and the push platform. The grooves 1436 and the cavity wall of the valve cavity form an oil passage, so that when the grease is squeezed by the plunger, it can flow out from between the matching surface and the sealing surface through the oil passage. Moreover, when the positioning cone surface 1433 contacts the conical sealing surface 1414, the front end surface of the push platform 1435 is in contact with the front end surface of the plunger 142 at the oil discharge limit position. The provision of the groove 1436 can ensure that the cross-section of the grease oil passage is large enough while the plunger 142 is not evacuated. This is because if the gap between the outer peripheral surface of the push platform 1435 and the wall of the valve chamber 1413 is to be as small as possible (the less gas stored, the less gas stored, the greater the suction force when the plunger 142 sucks in the next stroke, that is, the stored gas will affect the vacuum suction force of the plunger 142), the diameter of the push platform 1435 needs to be as large as possible. Under the premise of the same cross-sectional area of ​​the flow channel, the provision of the groove 1436 can make the grease flow cross-sectional area wider. The wider the cross-sectional area, the smaller the impact on the grease flow resistance. For example, a square (4*4) channel with a cross-sectional area of ​​16 has less impact on the grease flow resistance than a rectangular (1*16) channel with a cross-sectional area of ​​16. After the groove 1436 is set, when the plunger 142 is at the oil discharge limit position, the grease contains gas, and this part of the gas will only exist in the groove 1436. The gas is no longer stored between the plunger 142 and the valve core of the one-way valve 143. The volume of the gas stored in the groove 1436 is very limited, and the effect on the vacuum suction force of the next suction stroke of the plunger pair 14 is very small, thereby effectively alleviating the problem of the plunger 142 being evacuated.

[0072] like Figure 3 As shown, at least one radially extending stirring and cutting rod 15 is installed on the eccentric mechanism. When the stirring and cutting rod rotates with the eccentric mechanism, it can pass through the grease inlet, and is used to stir the grease, cut the bubbles in the grease, and apply the grease into the grease inlet. The stirring and cutting rod 15 can be installed on the eccentric by plug-in or threaded connection, and can be arranged along the radial direction of the eccentric. When the eccentric rotates, it can drive the stirring and cutting rod 15 to rotate. The stirring and cutting rod 15 has at least the following functions: first, it can stir the grease, make the grease more evenly distributed, and promote the downward creep of the grease; second, it can cut the large bubbles mixed in the grease into small bubbles, reduce the influence of the bubble plunger pair 14, and make it difficult for the plunger pair 14 to be emptied; third, it can drive the grease and apply it to the grease inlet 1411 of the plunger pair 14, so as to facilitate the plunger pair 14 to suck the grease.

[0073] Another embodiment of the plunger pair 14 of the utility model: Figure 8 As shown, the difference from the above embodiment is that the cross section of the groove on the pushing platform 1435 is arc-shaped.

[0074] Another embodiment of the plunger pair 14 of the utility model: Fig. 9 As shown, Figure 8 The difference between the corresponding embodiment is that the number of the grooves 1436 is changed to three evenly distributed in the circumferential direction, but the cross-sectional area of ​​each groove 1436 is appropriately increased.

[0075] Another embodiment of the plunger pair 14 of the utility model: Fig.10 As shown, Fig. 9 The difference between the corresponding embodiment is that six grooves 1436 are provided, evenly distributed in the circumferential direction, and the cross section of each groove 1436 is reduced by half.

[0076] Another embodiment of the plunger pair 14 of the utility model: Fig.11 As shown, the difference from the above embodiment is that the push platform 1435 is changed to a regular hexagonal cross-section, and the side of the push platform 1435 and the cavity wall of the valve cavity 1413 form a plurality of oil passages, and this embodiment constitutes 6 oil passages.

[0077] Another embodiment of the plunger pair 14 of the utility model: Fig.12 As shown, the difference from the above embodiment is that a guide platform 1439 is provided on the side of the positioning cone surface 1433 close to the reset spring 1437, the cross section of the valve cavity 1413 is circular, the maximum outer diameter of the guide platform 1439 is consistent with the inner diameter of the valve cavity 1413, so that the two can slide together, and an oil groove is also provided on the outer peripheral surface of the guide platform. This facilitates the installation of the valve core of the one-way valve 143 on the one hand, and enables the positioning cone surface 1433 and the conical sealing surface 1414 to cooperate faster and more accurately on the other hand. A sealing gasket is provided on the positioning cone surface, and a tighter seal is achieved by relying on the sealing gasket and the conical sealing surface.

[0078] Another embodiment of the plunger pair 14 of the utility model: Fig.13 As shown, the difference from the above embodiment is that the valve stem 1432 is no longer provided on the valve core of the one-way valve 143, but an annular groove 1438 is used to position the return spring 1437; wherein a sealing gasket 17 is provided at the positioning cone surface 1433, and the sealing gasket 17 is relied on to achieve sealing cooperation with the conical sealing surface 1414.

[0079] Another embodiment of the plunger pair 14 of the utility model: Fig.14As shown, the difference from the above embodiment is that the valve core is composed of two separate parts, which are positioned and plugged together through a socket structure 18. The two parts are respectively a front section with a positioning cone surface 1433 and a push platform 1435, and a rear section with a guide platform. A sealing gasket 17 is provided at the positioning cone surface 1433, and a sealing fit with the conical sealing surface 1414 is achieved by relying on the sealing gasket 17.

[0080] Another embodiment of the pump head assembly of the utility model: Fig.15 As shown, the difference from the above embodiment is that the position of the stirring and cutting rod is designed. For ease of understanding, it is first set that the plunger has a first valve position for blocking the fat inlet and a second valve position for reopening the fat inlet within a cycle of movement in the valve cavity. Fig.15 The eccentric wheel mechanism rotates clockwise, and the farthest position when the plunger moves toward the one-way valve is defined as the minimum eccentric position of the eccentric wheel mechanism. At the minimum eccentric position, the distance between the plunger and the rotation center of the eccentric wheel mechanism is the smallest. At the minimum eccentric position, the stirring and cutting rod has a certain angle with the plunger ( Fig.15 The angle is set so that when the plunger is between the first valve position and the second valve position, the stirring and cutting rod passes through the grease inlet. Setting the stirring and cutting rod within a certain angle range with the plunger at the minimum eccentric position can ensure that the grease is applied to the grease inlet by the stirring and cutting rod before the grease inlet is opened, so that when the grease inlet is opened, the vacuum suction of the plunger can directly suck away the grease that has been applied to the grease inlet. More importantly, when the grease inlet is opened, the vacuum suction of the plunger will suck out a cavity in the grease inlet and a certain area above the grease inlet. If the stirring and cutting rod applies grease to the grease inlet again at this time, the air in the cavity will inevitably be wrapped in the grease, which will cause the air to be easily evacuated during the next suction due to this part of the entrained air. Therefore, the setting position of the stirring and cutting rod is very critical. It is best to make the stirring and cutting rod apply the grease to the grease inlet before the grease inlet is opened to avoid the above situation.

[0081] A specific embodiment of the lubrication pump of the present invention: the lubrication pump includes a pump head assembly and an oil tank installed on the upper part of the pump head assembly for storing grease, the pump head assembly includes a motor, an eccentric wheel mechanism driven by the motor and a plunger pair 14 driven by the eccentric wheel mechanism, the structure of the plunger pair 14 is the same as the structure of the plunger pair 14 in the above-mentioned embodiments, and will not be repeated.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the description and drawings of the present invention shall be included in the protection scope of the present invention.

Claims

1. Plunger pair, including: The valve body has a valve cavity, and is provided with a grease inlet and a grease outlet communicating with the valve cavity, and a sealing surface opening outward is provided at the grease outlet; A plunger is slidably assembled in the valve cavity; A one-way valve, comprising a return spring and a sealing structure for blocking the grease outlet, the sealing structure comprising a valve core arranged at the grease outlet of the valve cavity, one end of the valve core being abutted against the return spring, and the other end being abutted against the sealing surface through a matching surface, the return spring providing the valve core with an elastic force to press the sealing surface; It is characterized in that An axially extending push platform is provided at one end of the valve core close to the plunger to reduce the air gap between the front end face of the push platform and the front end face of the plunger. At least one groove is provided on the outer peripheral surface of the push platform. The groove extends from the front end face of the push platform to the mating surface. The groove and the cavity wall of the valve cavity form an oil passage. When the grease is squeezed by the plunger, it can flow out from between the mating surface and the sealing surface through the oil passage.

2. The plunger pair according to claim 1, characterized in that: The sealing surface is conical, and the matching surface is conical.

3. The plunger pair according to claim 1 or 2, characterized in that: The sealing structure includes a sealing gasket which is pressed against the sealing surface to achieve sealing.

4. The plunger pair according to claim 1, characterized in that: The groove extends along the axial direction of the pushing platform.

5. The plunger pair according to claim 4, characterized in that: The cross section of the groove is C-shaped, rectangular or arc-shaped.

6. The plunger pair according to claim 4 or 5, characterized in that: There are multiple grooves, and the grooves are evenly distributed along the circumference of the push platform.

7. The plunger pair according to claim 1, characterized in that: The cross section of the valve cavity is circular, the cross section of the push platform is polygonal, and the side surface of the push platform and the cavity wall of the valve cavity form a plurality of oil passages.

8. The plunger pair according to claim 1, characterized in that: A valve stem is coaxially arranged on one side of the valve core close to the return spring, and the return spring is sleeved on the valve stem.

9. The plunger pair according to claim 1, characterized in that: An annular groove is provided on one side of the valve core close to the return spring, and the return spring is inserted into the annular groove.

10. The plunger pair according to claim 9, characterized in that: A guide platform is provided on one side of the valve core close to the return spring. The cross-section of the valve cavity is circular. The maximum outer diameter of the guide platform is consistent with the inner diameter of the valve cavity so that the two can be guided and slidably matched. An oil groove for grease to pass through is also provided on the outer peripheral surface of the guide platform.

11. A pump head assembly, characterized in that: The invention comprises a motor, an eccentric wheel mechanism driven by the motor, and at least one plunger pair as claimed in any one of claims 1 to 10 driven by the eccentric wheel mechanism.

12. The pump head assembly according to claim 11, characterized in that: At least one radially extending stirring and cutting rod is installed on the eccentric wheel mechanism. The stirring and cutting rod can pass through the grease inlet when rotating with the eccentric wheel mechanism, and is used for stirring the grease, cutting bubbles in the grease, and applying the grease into the grease inlet.

13. The pump head assembly according to claim 12, characterized in that: During one cycle of movement of the plunger in the valve chamber, there is a first valve position for blocking the fat inlet and a second valve position for reopening the fat inlet. The farthest position of the plunger when moving toward the one-way valve is defined as the minimum eccentric position of the eccentric wheel mechanism. At the minimum eccentric position, the stirring and cutting rod and the plunger have a certain angle, and the angle is set so that when the plunger is between the first valve position and the second valve position, the stirring and cutting rod passes through the fat inlet.

14. A lubrication pump, characterized in that: It comprises a pump head assembly as described in any one of claims 11 to 13 and an oil tank for storing grease, wherein the oil tank is connected to a grease inlet of a plunger pair in the pump head assembly.

Images