Pre-tightening-free supporting mechanism

Abstract

The utility model belongs to the technical field of hydraulic plunger pumps, and discloses a non-pre-tightening supporting mechanism which is used for being installed between a pump body and a built-in input shaft and comprises a cylindrical needle bearing in clearance fit with the upper position of the periphery of the input shaft and a cylindrical roller bearing matched with the lower position of the input shaft. The cylindrical needle bearing is mounted in a pump cover bearing hole, an inner ring of the needle bearing is in clearance fit with the peripheral surface of the input shaft, and an outer ring is in transition fit with the pump cover to realize flexible rotation; the outer ring of the cylindrical roller bearing is in clearance fit with a bearing hole in the pump body. According to the utility model, the stable operation of the plunger pump can be ensured without pre-tightening operation, the supporting precision of the cylinder body is improved, and the noise is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of pre-tightening support mechanism, belong to hydraulic ram pump technical field. BACKGROUND

[0002] Hydraulic ram pump is energy conversion device, the mechanical energy output by engine or motor is converted into hydraulic energy to drive the movement of working device.Input shaft is the link of energy conversion, in axial piston pump design, such as Figure 1 As shown in the input shaft one end is usually designed as involute external spline 1, it is connected with the output shaft end of engine or motor through coupling, the output speed and torque of engine or motor are transmitted to piston pump through involute spline.The middle position of input shaft is designed as involute external spline 2 structure, the speed and torque input through coupling are transmitted to piston pump cylinder, cam plate and push piston shoe assembly to do work on hydraulic pressure, so as to realize the conversion from mechanical energy to hydraulic energy.It can be seen that input shaft not only supports cylinder, but also acts as a bridge for energy conversion.

[0003] Traditional piston pump input shaft support mechanism needs to be installed with adjusting washer for pre-tightening, but in actual use, it is found that the mechanism needing pre-tightening not only requires high measurement accuracy during assembly, but also has problems caused by the pre-tightening adjusting mechanism due to the thermal expansion coefficient of materials: when pre-tightening is not enough, transmission shaft jumps, which leads to low input shaft support precision, noise and abnormal sound.Pretightening too much will lead to low transmission efficiency, increased contact surface pressure between rolling element and raceway, adhesion between rolling element and raceway, and premature failure of support bearing. CONTENT OF UTILITY MODEL

[0004] To solve the above technical problems, the utility model provides a kind of pre-tightening support mechanism, cancels the pre-tightening effect of adjusting washer, assembly process is simple, avoids the requirement of measurement;Second, there is no series of problems caused by over-tightening or insufficient pre-tightening;To ensure the stable operation of piston pump, improve cylinder support precision and reduce noise.

[0005] To achieve the above technical purposes and effects, the application realizes the following technical scheme: a kind of pre-tightening support mechanism is used to be installed between pump body and input shaft, including cylindrical needle bearing with input shaft outer peripheral position clearance fit and cylindrical roller bearing with input shaft lower position fit;Wherein, the cylindrical needle bearing is installed in pump cover bearing hole, needle bearing inner ring is clearance fit with input shaft outer peripheral surface, outer ring is transition fit with pump cover, to realize flexible rotation;The outer ring of cylindrical roller bearing is clearance fit with pump body bearing hole.

[0006] According to the utility model, further, the input shaft end face is limited to the cylindrical roller bearing end face, the cylindrical roller bearing outer ring is matched with the pump body inner bearing hole gap, and the inner end face of the pump body is used for limiting the cylindrical roller bearing end face, the freedom degree of the cylindrical roller bearing upward is limited, and the freedom degree of the input shaft upward is also limited.

[0007] According to the utility model, further, the input shaft is provided with an input shaft slot in the lower position, a shaft clamp spring is installed in the input shaft slot, and the freedom degree of the input shaft downward movement is limited.

[0008] According to the utility model, further, the input shaft is provided with an oil seal cover in the lower position, a skeleton oil seal is installed and placed in the oil seal cover inner hole, and the input shaft is sealed in rotation.

[0009] According to the utility model, further, an O-shaped ring slot is formed in the outer circle of the oil seal cover, an O-shaped ring is installed in the O-shaped ring slot, the hydraulic oil leakage is prevented, and the O-shaped ring outer circle is matched with the pump body inner hole gap.

[0010] According to the utility model, further, a clamp spring slot is formed in the position corresponding to the oil seal cover of the pump body, a hole clamp spring is embedded in the clamp spring slot, the axial position of the oil seal cover is limited, and the freedom degree of the cylindrical roller bearing downward movement is also limited.

[0011] The utility model provides a kind of pre-tightening support mechanism without, with following advantages:

[0012] The utility model provides a kind of pre-tightening support mechanism without, cancel the pre-tightening effect of adjusting gasket, assembly process is simple, avoids the requirement of measurement;Second, there is no noise, vibration and bearing overheating sintering damage problem caused by pre-tightening not enough or over-tightening;To ensure that plunger pump operates stably, improve cylinder support precision, reduce noise. ACCURACY

[0013] Figure 1 It is the structure schematic view of pre-tightening support mechanism in prior art for plunger pump;

[0014] Figure 2 It is the structure schematic view of pre-tightening support mechanism in prior art for plunger pump;

[0015] Wherein, 1-cylindrical roller bearing, 2-input shaft, 3-shaft clamp spring, 4-cylindrical roller bearing, 5-oil seal cover, 6-O-shaped ring, 7-hole clamp spring, 8-pump body, 9-clamp spring slot. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0017] Figure 1 It is a structural schematic diagram of a pre-tightening support mechanism of a plunger pump in the prior art, a hole is installed in a pump body snap spring groove by using a snap spring 6, an oil seal 5 is assembled into the pump body from above, and is limited by the snap spring 6. In order to prevent the oil seal 5 from interfering with the contact of the conical roller bearing 3, a check ring 4 is arranged therebetween to separate the two. The inner ring of the conical roller bearing 3 is in interference fit with the cylindrical surface of the input shaft, and the outer ring is in interference fit with the inner hole of the pump body, and the end face of the bearing inner ring limits the freedom of downward movement of the input shaft. The conical roller bearing 1 is installed in the bearing hole of the pump cover, and from the structure, it can be seen that the adjustment washer 7 placed on the transmission shaft is pressed towards the inner rings of the two conical bearings, and the bearing inner rings are pressed towards the roller 8, so that the roller 8 is tightly attached to the bearing outer ring.

[0018] The ideal pre-tightening here is that the thickness of the adjustment washer 7 is determined by measurement to make the roller 8 contact the bearing outer ring, but not generate surface pressure on the bearing outer ring, so as to ensure the transmission precision of the support cylinder body, and not cause contact surface pressure to cause bearing sintering wear. Of course, it is very difficult to achieve this ideal pre-tightening, and measurement error will cause under-pre-tightening or over-pre-tightening. Processing error will cause that even if the measurement is accurate, the adjustment washer with multiple size specifications is needed, so that the assembly consistency is poor. It can be seen that the pre-tightening support mechanism is difficult to apply.

[0019] As Figure 2 shown is a pre-tightening support mechanism provided by the present application, which comprises an input shaft 2 of a pump body 8, an outer periphery of an upper position of the input shaft 2 is matched with a needle bearing 1 in a gap, the needle bearing 1 is installed in a bearing hole of a pump cover, an outer ring of the needle bearing 1 is in transition fit with the pump cover, and an inner ring is matched with an outer periphery of the input shaft 2 in a small gap; an outer periphery of a lower position of the input shaft 2 is matched with a cylindrical roller bearing 4 in interference, an end face of the input shaft 2 limits an end face of the cylindrical roller bearing 4, the cylindrical roller bearing 4 is placed and installed in the pump body 8 together with the input shaft 2, an outer ring of the cylindrical roller bearing 4 is matched with an inner bearing hole of the pump body 8 in a small gap, an inner end face of the pump body 8 is used for limiting the end face of the cylindrical roller bearing 4, and limits the freedom of the cylindrical roller bearing 4 in the upward direction, and also limits the freedom of the input shaft 2 in the upward direction.

[0020] In the embodiments of the present application, the outer periphery of the input shaft 2 is also provided with a shaft snap spring 3 for limiting the freedom of downward movement of the input shaft, and the shaft snap spring 3 is installed in a groove at the lower position of the input shaft 2.

[0021] In the embodiment of the application, the outer periphery of the input shaft 2 is detachably fixed with an oil seal cover 5, the oil seal cover 5 is located below the cylindrical roller bearing 4, a skeleton oil seal is installed in the inner hole of the oil seal cover 5, and the oil seal cover 5 is used for the rotary sealing of the input shaft 2. An O-ring groove is formed on the outer circle of the oil seal cover 5 for installing an O-ring 6, so as to prevent hydraulic oil from leaking, and the outer circle is matched with the inner hole of the pump body 8 in a small gap.

[0022] Further, a snap spring groove 9 is formed at the position corresponding to the oil seal cover 5 of the pump body 8, a hole snap spring 7 is embedded in the snap spring groove 9, and the hole snap spring 7 is used for the axial positioning of the oil seal cover 5, and also limits the downward movement freedom of the cylindrical roller bearing 4.

[0023] The cylindrical roller bearing 4 and the needle bearing 1 replace the original large and small tapered roller bearings, the position of the shaft shoulder of the input shaft is changed, the snap spring groove 9 is additionally arranged, and the overall structure adopts a split oil seal cover 5. The cylindrical roller bearing 4 is in interference fit with the inner ring of the input shaft 2, is placed and installed in the pump body 8, and is limited in upward freedom by the inner shoulder of the pump body 8. The oil seal cover 5 is placed and installed in the pump body 8, the hole snap spring 7 is used for the axial positioning of the oil seal cover 5, and the shaft snap spring 3 limits the downward freedom of the input shaft 2. The needle bearing 1 is placed in the pump cover, the outer ring is in interference fit with the bearing inner hole of the pump cover, the inner ring is in clearance fit with the cylindrical surface of the input shaft 2, and flexible rotation can be realized, that is, stable transmission can be realized, and there is no need to realize stable transmission by pre-tightening.

[0024] The above is only a preferred embodiment of the present application, and is not any form and substantial limitation of the present application. It should be pointed out that, for ordinary skilled persons in the technical field, some improvements and supplements can be made without departing from the present application, and these improvements and supplements should be regarded as the protection range of the present application. For those skilled in the art, some changes, modifications and equivalent changes made by using the disclosed technical content without departing from the spirit and scope of the present application are equivalent embodiments of the present application; meanwhile, any equivalent change, modification and evolution of the above-mentioned embodiments according to the essential technology of the present application are still within the range of the technical solutions of the present application.

Claims

1. A preload-free support mechanism for installation between a pump body and an internal input shaft, characterized in that, It includes a cylindrical needle roller bearing with clearance fit to the upper part of the outer circumference of the input shaft and a cylindrical roller bearing with clearance fit to the lower part of the input shaft; wherein, the cylindrical needle roller bearing is installed in the bearing hole of the pump cover, the inner ring of the needle roller bearing has clearance fit to the outer circumference of the input shaft, and the outer ring has transition fit to the pump cover to achieve flexible rotation; the outer ring of the cylindrical roller bearing has clearance fit to the bearing hole inside the pump body.

2. The preload-free support mechanism as described in claim 1, characterized in that, The input shaft end face limits the cylindrical roller bearing end face. The outer ring of the cylindrical roller bearing is clearance-fitted with the bearing hole in the pump body. The inner end face of the pump body is used to limit the cylindrical roller bearing end face, restricting the upward degree of freedom of the cylindrical roller bearing, and also restricting the axial degree of freedom of the input shaft.

3. The preload-free support mechanism as described in claim 1, characterized in that, The input shaft has an input shaft groove located at a lower position, and a snap ring is installed in the input shaft groove to restrict the degree of freedom of the input shaft to move downward.

4. The preload-free support mechanism as described in claim 1, characterized in that, An oil seal cover is installed at a lower position on the input shaft, and a skeleton oil seal is installed in the inner hole of the oil seal cover for rotating sealing of the input shaft.

5. A preload-free support mechanism as described in claim 4, characterized in that, The outer circumference of the oil seal cover is provided with an O-ring groove, and the O-ring is installed in the O-ring groove to prevent hydraulic oil leakage. The outer circumference of the O-ring is in clearance fit with the inner bore of the pump body.

6. The preload-free support mechanism as described in claim 4, characterized in that, A retaining ring groove is provided at the position corresponding to the oil seal cover on the pump body. A retaining ring with a hole is embedded in the retaining ring groove to limit the axial movement of the oil seal cover, and at the same time restricts the downward movement freedom of the cylindrical roller bearing.

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