Plug screw for oil filler hole of differential mechanism of electric vehicle

Abstract

A screwed plug screw for an oil filler hole of a differential mechanism of an electric vehicle comprises a screwed plug screw body composed of a screwed plug screw rod (5), a screwed plug screw head (6) and a central exhaust hole (4), and is characterized in that the central exhaust hole at the screwed plug screw head (6) is provided with an internal thread and an inner-layer screw corresponding to the internal thread; and a transverse exhaust hole (7) is formed in the side surface of the screwed plug screw head (6) and is communicated with the central exhaust hole (4). The main innovation point is that an existing screwed plug screw is directly transformed, an inner layer screw and a nut are additionally arranged, the function of sealing exhaust holes during maintenance and transportation is added, meanwhile, three transverse exhaust holes are formed in the side face of a screw head of the existing screwed plug screw, a high-pressure oil and gas discharging path in a box body is forced to turn and reduce pressure, and the sealing function is achieved. Therefore, the purpose of smooth exhaust without oil spilling is achieved. The differential mechanism is simple in structure, low in manufacturing cost and easier to popularize and apply, and can be directly installed and used with a plug screw of an existing differential mechanism.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of electric vehicle transmission system spare and part design manufacturing technical field, specifically to a kind of electric vehicle differential oil filling hole plug screw. BACKGROUND

[0002] The differential housing used on electric vehicle is installed with gear set transmission motor power, and a small amount of lubricating oil is also installed, and the centrifugal force of lubricating oil is splashed by gear rotation to lubricate gear and bearing. The housing of differential is designed as closed state during operation. Lubricating oil must be replaced regularly to maintain gear, which requires setting oil filling hole on the top of gear housing and setting oil discharge hole on the bottom of housing. After replacing lubricating oil, oil filling hole and oil discharge hole must be plugged, so plug screw is designed.

[0003] When gear and bearing run at high speed, especially at high temperature, oil film is formed by high pressure rolling in the process of rotating toothed engagement between gears, which forms oil gas foam and makes the air pressure in differential housing increase. Overly high inflation air pressure can deform the oil seal on power shaft and lose the sealing effect of oil seal, causing lubricating oil to overflow. First, lubricating oil is lacking and gear is damaged, and second, the overflowed lubricating oil is transmitted to shaft head through power shaft, enters brake drum and loses brake effect, causing brake failure and safety accidents.

[0004] In order to solve the problem of air pressure increase in housing, the existing technology also provides a pressure relief vent to discharge high pressure oil gas. The differential vent on electric vehicle is set on the plug screw of oil filling hole of housing, which sets a through hole penetrating screw rod and screw head according to the vertical center line of plug screw, so that the plug screw has two functions.

[0005] The plug screw used at present is a relatively short bolt, and the exhaust hole is relatively short, with a length almost the same as the thickness of the housing. The lower end of the exhaust hole stands inside the housing, and the oil particles splashed by gear and oil gas from multiple points will be collected in the housing, so that more oil is directly splashed into the exhaust hole and easily discharged from the exhaust hole. Two adverse effects will occur, first, the overflowed oil will pollute the environment and vehicle body, and more importantly, the lack of lubricating oil will reduce the lubrication of gear, causing gear damage or scrap.

[0006] Due to the existence of exhaust hole, the existing technology also has a deficiency, that is, when the differential is installed, debugged, maintained and transported, the differential housing is inclined or inverted, and the lubricating oil will flow out of the exhaust hole and the oil amount will decrease. At this time, the existing technology can only take auxiliary measures to temporarily plug the exhaust hole, thus causing unnecessary trouble. SUMMARY

[0007] The utility model aims at solving the above-mentioned prior art problems. The task is to provide an electric vehicle differential oil injection hole plug screw, which effectively controls the internal air pressure of the box body, can normally discharge high-pressure air from the exhaust hole to the outside of the differential box body, and can also ensure that the lubricating oil remains in the box body, and the lubricating oil will not flow out of the exhaust hole when the differential box body is tilted and inverted during installation, debugging, maintenance and transportation of the differential.

[0008] The utility model is realized through the following technical schemes: an electric vehicle differential oil injection hole plug screw, which comprises a plug screw rod, a plug screw head and a central exhaust hole, characterized in that: the central exhaust hole at the plug screw head is provided with an internal thread and is provided with an inner layer screw composed of an inner layer screw rod and an inner layer screw head corresponding to the internal thread; the inner layer screw rod of the inner layer screw is provided with a nut; the side surface of the plug screw head is provided with a transverse exhaust hole and is in communication with the central exhaust hole.

[0009] The lower end of the inner layer screw rod is conical.

[0010] The transverse exhaust hole is provided with three holes in different directions on the side surface of the plug screw head and all converges at the central exhaust hole.

[0011] The three holes of the transverse exhaust hole are on the same horizontal plane, and the intersection point of the central exhaust hole is lower than the outer hole by 10 to 45 degrees.

[0012] The utility model has the following innovative points: the inner layer screw and the nut are added to the existing plug screw, the sealing function of the exhaust hole during maintenance and transportation is improved, and three transverse exhaust holes are additionally arranged on the side surface of the plug screw head of the existing plug screw, so that the high-pressure oil gas in the box body is diverted and decompressed, and smooth exhaust without oil overflow is achieved.

[0013] The utility model has the following advantages: the lubricating oil is retained in the box body without overflow, the gear and the bearing can be kept in good lubrication for a long time, the working efficiency and the mechanical noise reduction are significantly improved, the service life of the differential is greatly improved, and environmental pollution caused by oil overflow is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0014] The utility model will be further described in detail in combination with the drawings and specific embodiments.

[0015] Figure 1 The utility model is a structure schematic view when the exhaust hole is opened in the normal working state.

[0016] Figure 2 is a structural schematic view of the utility model in the exhaust hole closing state.

[0017] Figure 3 is a structure schematic view of prior art plug screw.

[0018] The figure is marked: 1-inner layer screw head, 2-nut, 3-inner layer screw rod, 4-central exhaust hole, 5-plug screw rod, 6-plug screw head, 7-transverse exhaust hole. DETAILED DESCRIPTION

[0019] As Figure 1 shown: a kind of electric vehicle differential oil injection hole plug screw, including plug screw rod (5) and plug screw head (6), central exhaust hole (4) is formed plug screw, it is characterized in that: the central exhaust hole at plug screw head (6) is provided with internal thread, and is provided with the inner layer screw that is correspondingly with internal thread by inner layer screw rod (3) and inner layer screw head (1) is formed;The inner layer screw rod (3) of the inner layer screw is provided with nut (2);The side of plug screw head (6) is provided with transverse exhaust hole (7), and is communicated with central exhaust hole (4).

[0020] The lower end of the inner layer screw rod (3) is conical.

[0021] The transverse exhaust hole (7) is respectively provided with 3 holes in the side of plug screw head (6) according to different directions, and all converge in central exhaust hole (4).

[0022] The 3 holes of the transverse exhaust hole (7) are on the same horizontal plane, and the intersection point of the central exhaust hole (4) is 10 to 45 degrees lower than the outer orifice.

[0023] Specific working principle and use method are as follows:

[0024] Referring to Figure 3 , the oil injection hole plug screw used on the existing electric vehicle differential is provided with pressure relief exhaust hole (4), and the exhaust hole is provided with a through hole penetrating the screw rod and the screw head according to the vertical center line of the plug screw, and the commonly used plug screw is a relatively short bolt, and the exhaust hole is relatively short, so that the oil splashed by the gear and oil gas in the box will directly splash on the exhaust hole (4), and it is easy to directly overflow from the exhaust hole. In order to solve this problem, the utility model is improved on the basis of the existing plug screw.

[0025] Referring to Figure 1, first the center exhaust hole at the place of the plug screw head (6) is provided with internal threads, and is provided with an inner layer screw corresponding to the internal threads, which is composed of an inner layer screw rod (3) and an inner layer screw head (1). When the differential is installed on an electric vehicle and is running normally, the inner layer screw rod (3) of the added inner layer screw is not completely screwed to the bottom, and is locked in the plug screw head by a nut (2), leaving a passage for the central exhaust hole (4) and the transverse exhaust hole (7), at this time the oil gas generated in the differential case will be blocked by the inner layer screw rod (3) and will be turned to reduce speed and become transverse. If there are oil particles carried in the oil gas that are impacted here to reduce speed, and because three transverse exhaust holes (7) are provided at the channel convergence place, the volume suddenly increases by three times, the pressure rapidly decreases, and the oil particles carried are impacted to reduce speed at the same time, and the power is further reduced. Due to gravity, the oil particles will flow back into the case along the channel of the transverse exhaust hole (7) provided with a slope. In this way, the exhaust is ensured at the same time as the lubricating oil is left in the case and does not overflow.

[0026] Referring to Figure 2 When the differential is assembled into a complete vehicle at the electric vehicle factory and needs to be transported or disassembled for maintenance, the inner layer screw rod (3) of the added inner layer screw is completely screwed to the bottom, and is locked in the plug screw rod (5) by a nut (2), the lower end of the inner layer screw rod (3) is conical, which is used as a conical needle valve at this time, at this time the needle valve blocks the passage of the central exhaust hole (4) and the transverse exhaust hole (7), the liquid lubricating oil in the disassembled differential case will be blocked by the inner layer screw rod (3) and cannot overflow. In this way, the oil flow phenomenon when tilting is prevented.

[0027] It is preferred to provide three transverse exhaust holes (7), mainly to reduce the pressure of the oil particles entering the central exhaust hole (4) at the intersection with the transverse exhaust hole (7), and to reduce the flow rate.

[0028] It is preferred that the intersection point of the three holes with the central exhaust hole (4) is 10 to 45 degrees lower than the outer hole, mainly to ensure that the oil particles that are still impacting the inner wall of the transverse exhaust hole (7) after being bent and turned by the transverse exhaust hole (7) to reduce pressure and speed will flow back to the case along the slope.

[0029] It is preferred that the diameter of the inner layer screw rod (3) is M5 or M6.

[0030] It is preferred that the diameter of the transverse exhaust hole (7) is 2 to 3 mm.

Claims

1. An electric vehicle differential oil filling hole plug screw, comprising a plug screw rod (5) and a plug screw head (6), a central exhaust hole (4) is formed, characterized in that: The central exhaust hole at the screw plug head (6) is internally threaded and is provided with an inner layer screw consisting of an inner layer screw rod (3) and an inner layer screw head (1) corresponding to the internal thread; the inner layer screw rod (3) of the inner layer screw is provided with a nut (2); the side surface of the screw plug head (6) is provided with a transverse exhaust hole (7) and is in communication with the central exhaust hole (4).

2. The electric vehicle differential oil fill plug screw of claim 1, wherein: The lower end of the inner layer screw rod (3) is conical.

3. The electric vehicle differential oil fill plug screw of claim 1, wherein: The transverse exhaust hole (7) is formed by three holes arranged at different positions on the side surface of the screw plug head (6) and all converging at the central exhaust hole (4).

4. The electric vehicle differential oil fill plug screw of claim 3, wherein: The three holes of the transverse exhaust hole (7) are on the same horizontal plane and the converging point of the central exhaust hole (4) is 10 to 45 degrees lower than the outer hole.

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