CN111828427B

CN111828427B - Oil hydraulic cylinder with floating type buffer bush

Info

Publication number: CN111828427B
Application number: CN201910378858.4A
Authority: CN
Inventors: 朱冏昇
Original assignee: Ashun Fluid Power Co ltd
Current assignee: Ashun Fluid Power Co ltd
Priority date: 2019-04-15
Filing date: 2019-05-08
Publication date: 2022-08-12
Anticipated expiration: 2039-05-08
Also published as: TW202040030A; CN111828427A; TWI705209B

Abstract

The invention provides an oil hydraulic cylinder with a floating type buffer bush, which comprises a front cylinder cover with a buffer groove, a piston rod penetrating through the front cylinder cover, a buffer bush sleeved on the piston rod and a supporting component. The buffer bush can be plugged into the buffer groove along with the advance of the piston rod. The supporting component is arranged between the buffer bush and the piston rod, so a gap is formed between the buffer bush and the piston rod, and the buffer bush can properly swing.

Description

Oil hydraulic cylinder with floating type buffer bush

Technical Field

The present invention relates to a hydraulic cylinder, and more particularly, to a hydraulic cylinder with a floating buffer bushing.

Background

Fig. 6 shows a conventional structure of a cushion type hydraulic cylinder, which includes a cylinder body 11 made of metal, a front cylinder head 12, a rear cylinder head 13, a piston 14, a piston rod 15, and a cushion bush 16 made of rubber. The front cylinder head 12 has a buffer groove 121 and a front oil inlet and outlet hole 122 communicating with each other, and the rear cylinder head 13 has a buffer groove 131 and a rear oil inlet and outlet hole 132 communicating with each other.

During a forward stroke, oil from a tank (not shown) enters from the rear inlet/outlet hole 132 and pushes the piston 14 forward from a point adjacent to the rear cylinder head 13 toward the front cylinder head 12, and the forward movement of the piston 14 pushes the oil in the cylinder 11 out of the front inlet/outlet hole 122 and flows back to the tank. When the piston 14 is about to reach a terminal point adjacent to the front cylinder head 12, the buffer bush 16 is first inserted into the buffer slot 121 (as shown by a chain line with two points in the figure) to decrease the discharge flow of the oil, so that the advancing speed of the piston 14 is decreased accordingly, and the piston 14 is prevented from violently impacting the front cylinder head 12 at the terminal point, thereby achieving the buffer effect.

In order to align the cushion bushing 16 with the cushion groove 121, prevent the cushion bushing 16 from being hard squeezed into the cushion groove 121 in a skewed posture, and even collide with the vicinity of an inlet 121A of the cushion groove 121 due to too much skew, a rod segment 151 of the piston rod 15 corresponding to the cushion bushing 16 must be precisely cut, and the cushion groove 121 must also be precisely cut so that the two have good concentricity after being assembled, so that the cushion bushing 16 fitted over the rod segment 151 can be aligned with the cushion groove 121 as desired.

However, the precision of the precision cutting is difficult to control accurately, and it is not ensured that the rod segment 151 of each piston rod 15 is concentric and circular without any error, and the same problem exists in the buffer groove 121 of the front cylinder head 12, and these errors will cause the buffer bush 16 to be prone to the skew, and cause the buffer bush 16 to be hard-pushed into the buffer groove 121 or collide with the buffer groove 121.

Disclosure of Invention

In view of the above problems, the present invention provides a hydraulic cylinder having a floating cushion bushing, including: a cylinder body; the front cylinder cover is arranged at the front end of the cylinder body and is provided with a shaft hole, a buffer groove and a front oil inlet and outlet hole, wherein the shaft hole and the buffer groove are coaxial and communicated, the front oil inlet and outlet hole is communicated with the buffer groove, and the buffer groove is communicated with the inside of the cylinder body and has an inner diameter smaller than that of the cylinder body; the rear cylinder cover is arranged at the rear end of the cylinder body and is provided with a rear oil inlet and outlet hole; a piston movably disposed in the cylinder; the piston rod is connected with the piston and penetrates through the buffer groove and the shaft hole of the front cylinder cover, the piston rod is provided with a rod section and a front rod section, the rod section is provided with an annular groove, the front rod section extends from the rod section to the front cylinder cover, and the front rod section is thicker than the rod section, so that a step is formed at the junction of the front rod section and the rod section; the supporting component is an annular body sleeved in the ring groove, and the annular body is partially embedded in the ring groove and partially positioned outside the ring groove; a buffer bush, which is sleeved on a rod section of the piston rod and positioned between the piston and the front cylinder cover and can be plugged into the buffer groove along with the advance of the piston rod, a front gap is arranged between the front end of the buffer bush and the step, and a rear gap is arranged between the rear end of the buffer bush and the piston, wherein, an inner wall of the buffer bush surrounds the rod section, and the inner wall is supported by the part of the annular body positioned outside the annular groove, so that a first gap and a second gap which are bound by the annular body are formed between the inner wall of the buffer bush and the rod section, and the buffer bush can swing back and forth by taking the annular body as a fulcrum.

In an embodiment of the present invention, the supporting member has elasticity and is pressed by the buffer bushing.

In one embodiment, the support assembly is located at or near a middle position of the cushion sleeve in an axial direction.

In one embodiment, the gap is between 0.1 and 0.3 mm.

Compared with the prior art, the buffer bush capable of properly swinging can be guided, so that a certain degree of processing error of the buffer grooves of the piston rod and the front cylinder cover is allowed, and the problem that the buffer bush is hard extruded into the buffer grooves or collides with the buffer grooves in the prior art can be solved. In addition, because the labor time is not needed to eliminate or reduce the processing errors, the manufacturing cost can be saved and the production speed can be improved.

Drawings

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes, the proportional sizes, and the like of the respective members in the drawings are merely schematic for facilitating the understanding of the present invention, and do not specifically limit the shapes, the proportional sizes, and the like of the respective members of the present invention. Those skilled in the art, having the benefit of the teachings of this invention, may choose from the various possible shapes and proportional sizes to implement the invention as a matter of case.

FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention.

Fig. 2 is a partial exploded view of the preferred embodiment at the location of the cushion bushing 26.

Fig. 3 is a close-up view of the preferred embodiment at the location of the cushion bushing 26.

Fig. 4 and 5 are schematic diagrams illustrating the deflection of the buffer bush 26 according to the preferred embodiment.

Fig. 6 is a sectional view of a conventional cushion type hydraulic cylinder.

Description of reference numerals:

11. 21 cylinder body

12. 22 front cylinder cover

121. 131 buffer groove

121A inlet

122 forward oil outlet

13. 23 rear cylinder cover

132 rear oil outlet

14. 24 piston

15. 25 piston rod

151. 251 pole segment

16. 26 buffer bush

221 axle hole

222 buffer tank

223 advancing oil outlet

233 rear oil outlet hole

231 buffer assembly

252 Ring groove

253 front rod segment

254 step

27 support assembly

G1 gap

G2 front clearance

G3 back clearance

G11 first gap

G12 second gap

Detailed Description

The details of the present invention can be more clearly understood in conjunction with the accompanying drawings and the description of the embodiments of the present invention. However, the specific embodiments of the present invention described herein are for the purpose of illustration only and are not to be construed as limiting the invention in any way. Any possible variations based on the present invention may be conceived by the skilled person in the light of the teachings of the present invention, and these should be considered to fall within the scope of the present invention.

Fig. 1 shows a preferred embodiment of the hydraulic cylinder of the present invention, which includes a cylinder body 21, a front cylinder head 22, a rear cylinder head 23, a piston 24, a piston rod 25, a cushion bush 26 and a support member 27. The front cylinder head 22 is disposed at a front end of the cylinder 21, and has a shaft hole 221 and a buffer slot 222 which are coaxial and communicated with each other, and a front oil inlet and outlet hole 223 communicated with the buffer slot 222. The buffer tank 222 communicates with the inside of the cylinder 21 and has an inner diameter smaller than that of the cylinder 21. The rear cylinder head 23 is provided at a rear end of the cylinder block 21 and has a rear oil inlet/outlet hole 233. The piston 24 is movably disposed in the cylinder 21. The piston rod 25 is connected to the piston 24 and extends to the outside space of the front cylinder head 22 after passing through the buffer groove 222 and the shaft hole 221 of the front cylinder head 22. The buffer bushing 26 is sleeved on a rod section 251 of the piston rod 25, is located between the piston 24 and the front cylinder head 22, and can be inserted into the buffer groove 222 along with the advance of the piston 24. A buffer component 231 is disposed on the rear cylinder cover 23 to prevent the piston 24 from violently colliding with the rear cylinder cover 23 when moving back toward the rear cylinder cover 23. The buffering element 231 is not necessary for the present invention and will not be described herein.

As shown in fig. 2 and 3, an inner wall 261 of the buffer sleeve 26 surrounds the rod segment 251, and a gap G1 is formed between the inner wall 261 and the rod segment 251. The support member 27 is disposed on the rod segment 251 and supports the inner wall 261 of the cushion bushing 26, such that the gap G1 is formed between the cushion bushing 26 and the rod segment 251.

Since the cushion bushing 26 does not entirely abut against the piston rod 25, but is supported by the support member 27 with the gap G1 between the cushion bushing 26 and the piston rod 25, the cushion bushing 26 is floatingly disposed on the piston rod 25, so that the cushion bushing 26 has a moderate yaw capability, as shown in fig. 4 and 5.

In an advancing stroke of the piston 24 being pushed to advance toward the front cylinder head 22, since the cushion bushing 26 has a moderate deflection capability, even if the cushion bushing 26 is not completely aligned with the buffer slot 222 due to machining errors of the rod section 161 and/or the buffer slot 222, the cushion bushing 26 is aligned if a front end of the cushion bushing 26 contacts any inner wall of the buffer slot 222, so as to avoid or reduce the probability that the cushion bushing 26 is hard squeezed into the buffer slot 222 or collides with the buffer slot 222. In other words, the cushion bushing 26 allows a certain degree of machining error and/or other errors between the piston rod 25 and the cushion groove 222, because the misalignment of the cushion bushing 26 with the cushion groove 222 caused by these errors can be effectively improved by the feature that the cushion bushing 26 can be aligned.

The supporting component 27 is mainly formed to form the gap G1, and its specific form is not limited to the one that can achieve the above purpose.

In one embodiment, the support member 27 is resilient and is slightly deformed by the cushion bushing 26, as shown in FIG. 3, to provide the cushion bushing 26 with a moderate degree of resilient deflection.

As shown in fig. 2 and 3, the support member 27 is preferably an annular body, such as an O-ring made of rubber, but not limited thereto, for example, the support member 27 may include a plurality of individual spaced-apart surrounding rod segments 251, each of which may be circular, conical or other shape. In addition, the rod segment 251 of the piston rod 25 preferably has an annular groove 252, and the annular body is partially embedded in the annular groove 252 and partially located outside the annular groove 252. The groove 252 is used to fix the support member 27 so that the support member 27 does not move arbitrarily. In one embodiment, the ring groove 252 may not be provided.

As shown in fig. 2 and 3, the piston rod 25 has a front rod segment 253, and the front rod segment 253 extends from the rod segment 251 toward the front cylinder head 22. Wherein the front segment 253 is thicker than the segment 251 such that the front segment 253 and the segment 251 interface to form a step 254. The step 254 stops in front of the cushion bushing 26. A front gap G2 is provided between a front end of the cushion bushing 26 and the step 254. A rear gap G3 is provided between a rear end of cushion liner 26 and piston 24. However, in one embodiment, the outer diameters of the front segment 253 and the segment 251 may be the same, and the step 254 and associated features are absent.

As shown in fig. 2, the supporting component 27 is preferably located at or near a middle position of the cushion bushing 26 in an axial direction, but not limited thereto, such as a forward position or a rearward position.

Preferably, the gap G1 is between 0.1mm and 0.3mm, and most preferably about 0.2mm, as is the front gap G2 and the rear gap G3, but not limited thereto.

In the above embodiment, the gap G1 includes a first gap G11 and a second gap G12, the first gap G11 and the second gap G12 are separated by the supporting member 27 without communication, in short, the first gap G11 and the second gap are bound by the supporting member 27. As a result, the entire cushion bushing 26 can be appropriately swung about the support member 27 as a fulcrum, as shown in fig. 4 and 5, in other words, the cushion bushing 26 can be swung back and forth about the support member 27 as a fulcrum, like a seesaw.

As described above, since the cushion bushing 26 of the present invention has the capability of appropriate yawing movement (i.e., the capability of swinging back and forth about the support member 27 as a fulcrum) by the support member 27 and the gap G1, it has a feature of being guided, which allows a certain degree of machining error in the cushion groove 222 of the piston rod 25 and the front cylinder head 22, and solves the problem that the cushion bushing is hard-pushed into the cushion groove or collides with the cushion groove due to the machining error in the past. In addition, because the machining errors are allowed, the labor time is not needed to eliminate or reduce the machining errors, and the effects of saving the manufacturing cost and improving the production speed are achieved.

The present invention is not limited to the above embodiments, and in particular, various features described in different embodiments can be arbitrarily combined with each other to form other embodiments, and the features are understood to be applicable to any embodiment except the explicitly opposite descriptions, and are not limited to the described embodiments.

Claims

1. An oil hydraulic cylinder with a floating cushion bushing, the oil hydraulic cylinder comprising:

a cylinder body;

the front cylinder cover is arranged at the front end of the cylinder body and is provided with a shaft hole, a buffer groove and a front oil inlet and outlet hole, wherein the shaft hole and the buffer groove are coaxial and communicated, the front oil inlet and outlet hole is communicated with the buffer groove, and the buffer groove is communicated with the inside of the cylinder body and has an inner diameter smaller than that of the cylinder body;

the rear cylinder cover is arranged at the rear end of the cylinder body and is provided with a rear oil inlet and outlet hole;

a piston movably disposed in the cylinder;

the piston rod is connected with the piston and penetrates through the buffer groove and the shaft hole of the front cylinder cover, the piston rod is provided with a rod section and a front rod section, the rod section is provided with a ring groove, the front rod section extends from the rod section to the front cylinder cover, and the front rod section is thicker than the rod section, so that a step is formed at the junction of the front rod section and the rod section;

the supporting component is an annular body sleeved in the ring groove, and the annular body is partially embedded in the ring groove and partially positioned outside the ring groove; and

a buffer bush, which is sleeved on a rod section of the piston rod and positioned between the piston and the front cylinder cover and can be plugged into the buffer groove along with the advance of the piston rod, a front gap is arranged between the front end of the buffer bush and the step, a rear gap is arranged between the rear end of the buffer bush and the piston, an inner wall of the buffer bush surrounds the rod section, and the inner wall is supported by the part of the annular body positioned outside the annular groove, so that a first gap and a second gap which are bounded by the annular body are formed between the inner wall of the buffer bush and the rod section, and the buffer bush can swing back and forth by taking the annular body as a fulcrum.

2. The hydraulic cylinder with a floating cushion bushing as claimed in claim 1, wherein the support member is resilient and is compressed against the cushion bushing.

3. A hydraulic cylinder with a floating cushion bushing according to claim 1 or 2, wherein the support member is located at or near a middle position of the cushion bushing in an axial direction.

4. The hydraulic cylinder with a floating cushion bushing as claimed in claim 1, wherein the first gap and the second gap are between 0.1mm to 0.3 mm.