Double-plunger sleeved type columnar hydraulic tappet

Abstract

The invention relates to a double-plunger sleeved type columnar hydraulic tappet which at least comprises a shell, an upper plunger, a lower plunger, a one-way valve mechanism and a return spring, the shell is provided with a plunger cavity and an oil inlet hole penetrating through the plunger cavity, the lower plunger is provided with an upper oil cavity and a lower oil cavity, the upper plunger is provided with an upper plunger inner cavity and a bottom opening, and the lower plunger is provided with a lower plunger inner cavity. The upper plunger is sleeved outside one side of the upper oil cavity of the lower plunger, the lower end of the upper plunger is provided with a first oil inlet channel communicated with the oil inlet hole, a second oil inlet channel communicated with the first oil inlet channel and the upper oil cavity is arranged between the upper plunger and the lower plunger, and the upper end opening of the upper oil cavity is higher than the first oil inlet channel. Compared with the prior art, the hydraulic tappet has the advantages that the structure that the upper plunger and the lower plunger are sleeved is adopted, the oil storage volume of the low-pressure cavity can be enlarged, the low-pressure cavity is provided with enough oil under the condition that the overall size of the hydraulic tappet is not changed, and therefore the risk that the valve clearance cannot be eliminated due to the fact that the hydraulic tappet is soft is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine accessory manufacturing, in particular to a double-plunger nested cylindrical hydraulic tappet. BACKGROUND

[0002] When the engine valve is in a closed state, the gap between the valve and the transmission member is called the valve gap. The valve system needs to reasonably control the valve gap to ensure the normal function of the system. The hydraulic tappet has the function of compensating the valve gap, which can reduce the impact and noise of the valve train, the wear of each working surface of the valve train, and improve the emission and combustion efficiency of the engine. When the valve system is working, the hydraulic tappet is subjected to transmission pressure, and the oil in the high-pressure cavity generates transient high pressure and is discharged from the oil discharge channel; and after the hydraulic tappet loses external pressure, the high-pressure cavity extracts oil from the low-pressure cavity for recovery and compensation of the valve gap, and so on.

[0003] When the low-pressure cavity of the hydraulic tappet is in a full-oil state, it can meet the demand for oil replenishment of the high-pressure cavity. However, the overall size of the existing hydraulic tappet is limited by factors such as response speed and installation space, so that the internal volume of the hydraulic tappet is limited. Among them, the oil storage volume of the low-pressure cavity is limited by the height of the plunger oil hole, and considering the strength of the top of the plunger and the need for exhaust when oil is added, the position of the plunger oil hole cannot be too high, but if the external oil supply system does not supply oil in time, it will also result in less oil storage in the low-pressure cavity.

[0004] In the prior art, under the condition that the overall size of the hydraulic tappet is unchanged, the method for increasing the oil storage volume of the low-pressure cavity, such as Chinese patent document CN103939162B, discloses a cylindrical hydraulic tappet, the plunger is composed of a closed hemispherical head, a rod and a main body, and a concave neck is arranged between the head and the rod of the plunger. The wall thickness of the neck is 105% to 120% of the wall thickness of the rest of the plunger, which increases the fatigue strength of the hydraulic tappet and provides sufficient safety factor. Then the plunger oil hole is tangent to the upper transition chamfer of the concave wide annular groove by blanking processing, or is arranged on the transition chamfer of the concave wide annular groove of the plunger by electrochemical machining, so that the position of the plunger oil hole is as high as possible, and the low-pressure cavity can store more hydraulic medium. However, this scheme increases the overall machining requirement of the plunger, reduces the production efficiency and yield, and the improved oil storage volume is also limited.

[0005] Under the condition that the overall size of the hydraulic tappet is unchanged, by increasing the strength of the weak area of the plunger and improving the position of the plunger oil hole, the processing requirement is higher, the production efficiency and the yield are reduced, and the oil storage volume of the low-pressure cavity is limited. Therefore, the existing hydraulic tappet still has the risk that the valve gap cannot be eliminated due to insufficient oil supplement from the low-pressure cavity to the high-pressure cavity under extreme working conditions such as engine cold start when the low-pressure cavity is in a non-full oil state, especially when the oil supply is not timely and the oil storage amount of the low-pressure cavity is small. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a double-plunger nested columnar hydraulic tappet, which can make the low-pressure cavity have sufficient oil under the condition that the overall size of the hydraulic tappet is unchanged, thereby avoiding the risk that the hydraulic tappet becomes soft and the valve gap cannot be eliminated during engine cold start.

[0007] To solve the above technical problems, the technical scheme provided by the present application is as follows: a double-plunger nested columnar hydraulic tappet, at least comprising: a housing, the housing is provided with a plunger cavity and an oil inlet hole penetrating into the plunger cavity; a lower plunger, the lower plunger is provided with an upper oil cavity, a lower oil cavity, and a valve hole communicating the upper oil cavity and the lower oil cavity, the lower plunger is installed at the bottom of the plunger cavity; an upper plunger, the inside of the upper plunger is provided with an upper plunger inner cavity, the bottom is provided with a bottom opening, the upper plunger is sleeved on the outside of one side of the upper oil cavity of the lower plunger, the lower end of the upper plunger is provided with a first oil inlet channel communicating with the oil inlet hole, a second oil inlet channel communicating the first oil inlet channel and the upper oil cavity is arranged between the upper plunger and the lower plunger, and the height of the upper end opening of the upper oil cavity is higher than that of the first oil inlet channel; a one-way valve mechanism, the one-way valve mechanism is arranged between the lower plunger and the bottom of the plunger cavity, and is used for controlling the opening and closing of the valve hole; a return spring, the return spring is arranged between the lower plunger and the bottom of the plunger cavity, and the side of the lower oil cavity of the lower plunger and the inner wall of the plunger cavity form a high-pressure oil storage cavity.

[0008] The beneficial effect of this scheme is that, compared with the hydraulic tappet with a single plunger structure in the prior art, in the present application, the single plunger is changed into a structure in which the upper plunger and the lower plunger are sleeved, the upper oil cavity side of the lower plunger is connected in sleeve with the bottom opening of the upper plunger, the top end of the outer wall of the upper oil cavity side of the lower plunger can continue to extend upward, which is conducive to expanding the oil storage volume of the low-pressure cavity, and under the condition that the overall size of the hydraulic tappet is unchanged, the low-pressure cavity has enough oil, thereby avoiding the risk that the hydraulic tappet becomes soft to cause the valve clearance to be unable to be eliminated when the engine is cold started. In addition, compared with the machining of the single plunger, the machining of the upper plunger and the lower plunger is easier to discharge machining waste, improves the production efficiency and the yield of finished products, and thus reduces the cost.

[0009] Further, the first oil inlet channel is an end face oil groove provided at the bottom of the upper plunger.

[0010] The beneficial effect of this scheme is that the first oil inlet channel is an end face oil groove at the bottom of the upper plunger, which can be directly machined by cold heading forming, thereby improving the production efficiency.

[0011] Further, the first oil inlet channel is a side face oil hole penetrating from the side wall of the upper plunger to the inner cavity of the upper plunger.

[0012] Further, the second oil inlet channel is an inner oil groove provided on the inner wall of the upper plunger.

[0013] Further, the second oil inlet channel is an outer oil groove provided on the outer wall of the lower plunger.

[0014] Further, the second oil inlet channel is a gap between the upper plunger and the lower plunger.

[0015] Further, the top of the upper oil cavity side of the lower plunger converges inward.

[0016] Further, a snap spring is further included, the upper plunger is provided with an external ring groove, and the snap spring is arranged in the external ring groove. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structural schematic view of a double-plunger sleeved cylindrical hydraulic tappet according to the present embodiment.

[0018] Figure 2 It is a front view of the internal structure of the upper plunger according to the present embodiment.

[0019] Figure 3 It is a side view of the internal structure of the upper plunger according to the present embodiment.

[0020] Figure 4 It is a schematic view of the internal structure of the lower plunger according to the present embodiment.

[0021] Figure 5 Fig. 4 is a schematic view of another internal structure of the lower plunger in the embodiment.

[0022] Figure 6 Fig. 5 is a schematic view of the highest oil storage surface of the low pressure cavity of the existing cylindrical hydraulic tappet.

[0023] Figure 7 Fig. 6 is a schematic view of the highest oil storage surface of the low pressure cavity in the embodiment.

[0024] Figures 1-7 In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. 1, housing; 10, plunger cavity; 101, high pressure oil storage cavity; 102, oil drain ring; 11, oil inlet hole; 2, upper plunger; 20, upper plunger inner cavity; 21, bottom opening; 22, first oil inlet passage; 23, second oil inlet passage; 24, outer ring groove; 25, top opening; 3, lower plunger; 301, upper oil cavity; 302, lower oil cavity; 31, valve hole; 32, upper end opening; 33, top; 4, one-way valve mechanism; 41, one-way valve ball; 42, one-way valve spring; 43, one-way valve spring seat; 5, return spring; 6, snap spring; 7, highest oil storage surface; 8, plunger oil hole. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0026] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0027] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, integrally connected, or detachably connected; it can be the communication between the two elements; it can be directly connected, or indirectly connected through an intermediate medium; for those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] As shown in Figure 1 The double-plunger sleeve type cylindrical hydraulic tappet of the embodiment includes a shell 1, an upper plunger 2, a lower plunger 3, a one-way valve mechanism 4, a return spring 5, and a snap spring 6. The shell 1 is provided with a plunger cavity 10 and an oil inlet hole 11 penetrating the plunger cavity 10. The upper plunger 2 and the lower plunger 3 are both arranged in the plunger cavity 10, with the upper plunger 2 above the lower plunger 3.

[0029] As a special feature of the embodiment, the structure of the upper plunger 2 is as shown in Figures 2-3 The upper plunger 2 is internally provided with an upper plunger inner cavity 20 and externally provided with a bottom opening 21. Figures 4-5 As shown in The lower plunger 3 is provided with an upper oil cavity 301, a lower oil cavity 302, and a valve hole 31 connecting the upper oil cavity 301 and the lower oil cavity 302. The upper oil cavity 301 of the lower plunger 3 is connected to the upper plunger inner cavity 20 through the bottom opening 21, so that the upper plunger 2 is sleeved on the outside of the upper oil cavity 301 of the lower plunger 3. The upper plunger 2 is provided with a first oil inlet passage 22 connecting the oil inlet hole 11 and the upper plunger inner cavity 20. The upper plunger 2 and the lower plunger 3 are provided with a second oil inlet passage 23 connecting the first oil inlet passage 22 and the upper oil cavity 301. The height of the upper end opening 32 of the upper oil cavity 301 is higher than that of the first oil inlet passage 22.

[0030] The advantage of such a structure is that, compared with the hydraulic tappet with a single-plunger structure in the prior art, the single plunger is replaced by the sleeved structure of the upper plunger 2 and the lower plunger 3 in the embodiment. The upper oil cavity 301 of the lower plunger 3 is connected to the bottom opening 21 of the upper plunger 2. The outer wall of the upper oil cavity 301 of the lower plunger 3 can continue to extend upward, which is conducive to expanding the oil storage volume of the low-pressure cavity and ensuring sufficient oil in the low-pressure cavity while the overall size of the hydraulic tappet remains unchanged, thereby avoiding the risk of softening of the hydraulic tappet and failure to eliminate the valve clearance during cold start of the engine.

[0031] Figure 6 To more intuitively illustrate the oil storage volume of the low-pressure cavity in the embodiment, when the external oil supply system fails to timely input oil into the oil inlet hole 11 of the shell 1 of the hydraulic tappet, the highest oil storage surfaces of the low-pressure cavity of the existing cylindrical hydraulic tappet and the low-pressure cavity of the embodiment are as shown in Figure 7The highest oil storage surface 7 in the low-pressure cavity of the existing cylindrical hydraulic tappet does not exceed the plunger oil hole 8. In the embodiment, the highest oil storage surface 7 is the upper end surface where the upper end opening 32 of the upper oil cavity 301 is located after the upper plunger 2 and the lower plunger 3 are connected in a sleeve manner. It should be noted that in the embodiment, the position of the first oil inlet channel 22 corresponds to the position of the plunger oil hole 8 of the existing cylindrical hydraulic tappet. Therefore, when the upper end surface where the upper end opening 32 of the upper oil cavity 301 is located is higher than the first oil inlet channel 22, the highest oil storage surface 7 of the embodiment is higher than that of the existing cylindrical hydraulic tappet, so that the oil storage volume of the low-pressure cavity can be expanded under the condition that the overall size of the hydraulic tappet is unchanged.

[0032] Another advantage of such an arrangement is that, in the manufacturing process, the upper plunger 2 and the lower plunger 3 are easier to discharge machining waste than a single plunger, thereby improving production efficiency and yield and reducing costs.

[0033] In the embodiment, the one-way valve mechanism 4 is arranged between the lower plunger 3 and the bottom of the plunger cavity 10. The one-way valve mechanism 4 includes a one-way valve ball 41, a one-way valve spring 42, and a one-way valve spring seat 43. The one-way valve ball 41 is arranged at the valve hole 31 of the lower plunger 3, so that the one-way valve mechanism 4 is used to control the opening and closing of the valve hole 31. The one-way valve spring seat 43 is connected to the one-way valve ball 41 through the one-way valve spring 42.

[0034] In the embodiment, the return spring 5 is arranged between the lower plunger 3 and the bottom of the plunger cavity 10. At this time, the lower oil cavity 302 of the lower plunger 3 and the inner wall of the plunger cavity 10 form a high-pressure oil storage cavity 101, and the side wall of the lower plunger 3 and the inner wall of the plunger cavity 10 form a drain ring 102 that communicates the high-pressure oil storage cavity 101 and the oil inlet hole 11.

[0035] In the embodiment, the structure of the upper plunger 2 is as shown in Figures 2-3 The upper plunger 2 is provided with a top opening 25, which can output oil upward for lubrication of the ball socket and the roller of the engine. Preferably, in the embodiment, the upper plunger 2 is also provided with an external ring groove 24, and the snap spring 6 is arranged in the external ring groove 24.

[0036] Preferably, in the embodiment, the first oil inlet channel 22 is an end face oil groove arranged at the bottom of the upper plunger 2. The advantage of such an arrangement is that the first oil inlet channel 22 is an end face oil groove at the bottom of the upper plunger 2, which can be directly processed by cold heading forming, thereby improving production efficiency.

[0037] It should be noted that in the present embodiment, the first oil inlet channel 22 is an end face oil groove provided at the bottom of the upper plunger 2, which is only a preferred embodiment of the present embodiment, and those skilled in the art should understand that the first oil inlet channel 22 can also be a side oil hole of the side wall of the upper plunger 2 penetrating into the inner cavity 20 of the upper plunger.

[0038] As preferred, in the present embodiment, the second oil inlet channel 23 is an inner oil groove provided on the inner wall of the upper plunger 2. The external oil liquid enters the inner cavity 20 of the upper plunger 2 through the oil inlet hole 11 of the housing 1 and the first oil inlet channel 22 of the upper plunger 2 in sequence, and then rises along the second oil inlet channel 23 and quickly enters the upper oil cavity 301 of the lower plunger 3.

[0039] It should be noted that in the present embodiment, the second oil inlet channel 23 is an inner oil groove provided on the inner wall of the upper plunger 2, which is only a preferred embodiment of the present embodiment, and those skilled in the art should understand that the second oil inlet channel 23 can also be an outer oil groove provided on the outer wall of the lower plunger 3, or a gap between the upper plunger 2 and the lower plunger 3.

[0040] As preferred, in the present embodiment, the lower plunger 3 of the first embodiment is as shown in Figure 4 , the top 33 of the lower plunger 3 converges inwardly. Figure 5 As preferred, in the present embodiment, the lower plunger 3 of the second embodiment is as shown in

[0041] In summary, the above only describes the preferred embodiments of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A double-piston sleeve-fit cylindrical hydraulic jack, characterized by, At least comprising: a housing (1) provided with a plunger cavity (10) and an oil inlet hole (11) penetrating to the plunger cavity (10); a lower plunger (3) provided with an upper oil cavity (301), a lower oil cavity (302) and a valve hole (31) connecting the upper oil cavity (301) and the lower oil cavity (302), the lower plunger (3) being installed at the bottom of the plunger cavity (10); an upper plunger (2) provided with an upper plunger inner cavity (20) inside and a bottom opening (21) at the bottom, the upper plunger (2) being sleeved outside the upper oil cavity (301) side of the lower plunger (3), the lower end of the upper plunger (2) being provided with a first oil inlet channel (22) communicating with the oil inlet hole (11), a second oil inlet channel (23) communicating the first oil inlet channel (22) and the upper oil cavity (301) being provided between the upper plunger (2) and the lower plunger (3), the height of the upper end opening (32) of the upper oil cavity (301) being higher than the first oil inlet channel (22); a one-way valve mechanism (4) provided between the lower plunger (3) and the bottom of the plunger cavity (10) for controlling the opening and closing of the valve hole (31); a return spring (5) provided between the lower plunger (3) and the bottom of the plunger cavity (10), the lower oil cavity (302) side of the lower plunger (3) and the inner wall of the plunger cavity (10) forming a high-pressure oil storage cavity (101).

2. The dual plunger nested cylindrical hydraulic lifter of claim 1 wherein, The first oil inlet channel (22) is an end face oil groove provided at the bottom of the upper plunger (2).

3. The dual plunger nested cylindrical hydraulic lifter of claim 1 wherein, The first oil inlet channel (22) is a side oil hole penetrating from the side wall of the upper plunger (2) to the upper plunger inner cavity (20).

4. The dual plunger nested cylindrical hydraulic lifter of claim 1 wherein, The second oil inlet channel (23) is an inner oil groove provided on the inner wall of the upper plunger (2).

5. The dual plunger nested cylindrical hydraulic lifter of claim 1 wherein, The second oil inlet channel (23) is an outer oil groove provided on the outer wall of the lower plunger (3).

6. The dual plunger nested cylindrical hydraulic lifter of claim 1 wherein, The second oil inlet channel (23) is the gap between the upper plunger (2) and the lower plunger (3).

7. The dual plunger nested cylindrical hydraulic lifter of claim 1 wherein, The top (33) of the lower plunger (3) converges inwardly.

8. The dual plunger nested cylindrical hydraulic lifter of claim 1 wherein, Further comprising a snap spring (6), the upper plunger (2) being provided with an external ring groove (24), the snap spring (6) being provided in the external ring groove (24). Further comprising a snap spring (6), the upper plunger (2) being provided with an external ring groove (24), the snap spring (6) being provided in the external ring groove (24).

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