JP2004245390A - Hydraulic joint and shaft connection mechanism using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic joint capable of reducing the ocurrence of fatigue destruction without increasing weight and material cost irrespective of restrictions in outer dimension. <P>SOLUTION: This hydraulic joint 11 is provided with an annular liquid chamber part 12 extending in the axial direction and a swelling part 11a constituted so as to swell by pressure of liquid pressed in the liquid chamber part. A value (L1/L2) obtained by dividing distance L1 from an end face 11a of the hydraulic joint 11 to an end face 12a of the liquid chamber part 12 by length L2 in the axial direction of the liquid chamber part is set to a scope of 0.06 to 0.08. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic coupling used for a drive device of a rolling mill, for example, and a shaft coupling mechanism using the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a driving device of a rolling mill, a driving-side rotating shaft (hereinafter, also referred to as a “driving shaft”) and a driven-side rotating shaft (hereinafter, referred to as a “driven shaft”) that is internally or externally separated from the driving shaft. ) Is connected and fixed without transmitting the play of the drive shaft to the driven shaft, and the hydraulic joint is used to transmit the torque.
For example, as shown in FIG. 4, this hydraulic coupling is entirely cylindrical and has an annular liquid chamber portion 2 extending in the axial direction therein, and an inner peripheral surface of the liquid chamber portion 2. And a thin bulging portion 3 located on the side (for example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent No. 2784881 (page 2, FIG. 5)
[0004]
[Problems to be solved by the invention]
In the above-described conventional hydraulic coupling 1, when hydraulic oil is press-fitted into the liquid chamber 2 from a liquid inlet (not shown), the hydraulic pressure acts on the inner wall surface of the liquid chamber 2 so that the thin wall is formed. The bulging portion 3 is pushed out. When it bulges as shown by the broken line 3a in the figure, it comes into pressure contact with the drive shaft 4, and the drive shaft 4 comes into pressure contact with the driven shaft 5, whereby the drive shaft 4 and the driven shaft 5 are connected. Such connection is repeatedly performed by a hydraulic control unit (not shown). For this reason, a large tensile stress or a large compressive stress is repeatedly applied to the vicinity of both ends of the liquid chamber portion 2, and thus there is a problem that fatigue fracture easily occurs.
[0005]
To solve this problem, it is conceivable to increase the mechanical strength by increasing the thickness in the vicinity of both ends of the liquid chamber portion 2. Since the length in the axial direction is shortened, the length in the axial direction of the bulging portion 3 pressed against the drive shaft 4 is also reduced, so that the play of the drive shaft 4 cannot be sufficiently eliminated. On the other hand, if the axial length of the liquid chamber portion 2 is made to be a sufficient length after both the outer sides in the axial direction of the liquid chamber portion 2 are made thicker, the overall size of the hydraulic coupling 1 becomes large. It becomes difficult to attach to various devices. Therefore, it is important how to improve the fatigue strength without increasing the external dimensions.
[0006]
By the way, Patent Literature 1 discloses a method of providing a slope such that the inner peripheral sides of both ends of the liquid chamber 2 are thick. According to this measure, the outer peripheral side of the liquid chamber 2 at both ends is not made thicker but thicker on the inner peripheral side, so that the fatigue strength can be improved without increasing the external dimensions. However, increasing the thickness of the inner peripheral sides of both ends of the liquid chamber portion 2 leads to an increase in weight and an increase in material cost, and thus cannot always be said to be the best measure for improving fatigue strength.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and even when there are restrictions on external dimensions, a hydraulic joint having improved fatigue strength and a hydraulic joint having improved fatigue strength are provided without increasing weight or increasing material costs. It is an object of the present invention to provide a shaft connecting mechanism.
[0008]
[Means for Solving the Problems]
The present inventor examined the stress acting near both ends of the liquid chamber by FEM analysis (finite element analysis) in order to reduce the stress generated near both ends of the liquid chamber. It was found that there was a peculiar relationship with the stress acting near both ends of the part. That is, in order to reduce the stress, as described above, the portion may be made thicker. However, if both the outer sides in the axial direction of both ends of the liquid chamber portion are made too thick, a large stress may be applied instead. It was found that fatigue fracture easily occurs. Therefore, as a result of repeated experiments on the dimensions of the liquid chamber where the stress acting on the vicinity of both ends of the liquid chamber decreases, the present invention has been completed.
[0009]
That is, the hydraulic joint of the present invention includes an annular liquid chamber portion extending in the axial direction, and a swelling portion that swells due to the pressure of the liquid press-fitted into the liquid chamber portion. Swelling, a first rotating shaft that is fitted or separated from the bulging portion, or a second rotating shaft that is fitted or separated from the first rotating shaft. In which the distance (L1 / L2) obtained by dividing the distance L1 from the end face of the hydraulic joint to the end face of the liquid chamber part by the axial length L2 of the liquid chamber part is 0.06 or more. It is characterized in that it is set in the range of 0.08.
[0010]
According to the above configuration, even when the swelling portion is repeatedly swelled to repeatedly connect the first rotating shaft and the second rotating shaft, it is possible to reduce the stress applied to a portion where fatigue failure easily occurs. Further, since both outer sides in the axial direction of both ends of the liquid chamber portion can be made thin, it is possible to suppress an increase in weight and material cost, and to reduce the possibility of causing dimensional defects in mounting to various devices. Here, if L1 / L2 is less than 0.06, both ends in the axial direction at both ends of the liquid chamber portion are too thin, resulting in insufficient mechanical strength. If L1 / L2 exceeds 0.08, It is considered that both sides in the axial direction at both ends of the liquid chamber portion are too thick to bend easily and cause stress concentration, but rather fatigue fatigue is likely to occur.
Here, in the present invention, the “distance L1 from the end face of the hydraulic joint to the end face of the liquid chamber portion” refers to one of the liquid chamber portions located at the shortest position axially inward from one end face of the hydraulic joint. And the average of the distance from the other end face of the hydraulic coupling to the other end face of the liquid chamber portion at the shortest position inward in the axial direction.
[0011]
The shaft coupling mechanism according to the present invention includes a first rotating shaft, a second rotating shaft that is provided internally or externally at a distance from the first rotating shaft, and an external device that contacts or separates from the first rotating shaft. Alternatively, it is characterized by including the above-mentioned hydraulic coupling to be installed therein. According to the above configuration, since the hydraulic coupling with improved fatigue strength is used, for a long period of time, the backlash of one rotating shaft is connected and fixed without transmitting to the other rotating shaft to transmit the torque. It becomes possible.
Here, the shaft connecting mechanism of the present invention includes a first rotating shaft, a second rotating shaft which is housed separately from the first rotating shaft, and a contacting or separating member with the first rotating shaft. A first rotary shaft, a second rotary shaft that is provided separately from the first rotary shaft, and the first rotary shaft. And the above-mentioned hydraulic coupling which is provided in contact with or separated therefrom.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial cross-sectional view schematically showing a main configuration of a shaft coupling mechanism including a hydraulic coupling according to an embodiment of the present invention. The shaft coupling mechanism includes a cylindrical rotating shaft (driving shaft) 13 as a first rotating shaft on a driving side and a cylindrical inner space separated from an inner peripheral surface 13 b on one end side of the driving shaft 13. And a cylindrical metal (for example, shrink-fit) which is in contact with the driven-side rotating shaft (driven shaft) 14 as a second rotating shaft and the outer peripheral surface 13a at one end of the driving shaft 13. The hydraulic coupling 11 is provided. The drive shaft 13 and the driven shaft 14 are arranged coaxially with each other. However, when the drive shaft 13 is backlashed, the two shafts may not be coaxial.
[0013]
The hydraulic joint 11 has an annular liquid chamber portion 12 extending in the axial direction therein and a pressure of the liquid press-fitted into the liquid chamber portion 12 located on the inner peripheral surface 11 c side of the liquid chamber 12. And a bulging portion 11b that bulges.
[0014]
The liquid chamber portion 12 has an axial length L2, and has an end surface 12a at a position slightly closer to the inner peripheral surface 11c inside the hydraulic coupling 11 and at the same distance L1, L1 from both end surfaces 11a. It is formed so that it may be located. In addition, both ends of the liquid chamber 12 are formed so as to be enlarged as compared with the center.
The bulging portion 11b is a thin portion located closer to the inner peripheral surface 11c than the liquid chamber portion 12, and is formed so as to bulge by the pressure of the liquid press-fitted by a liquid pressure control means (not shown).
[0015]
In such a hydraulic joint 11, a value (L1 / L2) obtained by dividing the distance L1 from the end face 11a of the hydraulic joint 11 to the end face 12a of the liquid chamber part 12 by the axial length L2 of the liquid chamber part 12 is obtained. It is set in the range of 0.06 to 0.08. When the range is set in such a range, the stress acting on both ends of the liquid chamber portion 12 is reduced, so that the occurrence of fatigue fracture is reduced.
[0016]
FIG. 2 shows the distance L1 from the end face 11a of the hydraulic coupling 11 to the end face 12a of the liquid chamber section 12 and the measuring section A (FIG. 1) when the axial length L2 of the liquid chamber section 12 is constant (226 mm). FIG. 7 is a graph showing a relationship with stress acting on the reference (see FIG. 1). The stress acting on the measurement portion A was obtained by FEM analysis (finite element analysis), and the vertical axis in FIG. 2 was the ratio to the stress (σmax0) of the reference sample. Here, the measurement of the stress at the measurement section A is easy to measure, and data substantially equivalent to the portion where the fatigue fracture is most likely to occur (the inner circumferential side at both ends of the liquid chamber section 12) is obtained. For reasons such as.
[0017]
FIG. 2 shows that when L1 is 14.5 mm (L1 / L2 = 0.064) and 17.0 mm (L1 / L2 = 0.075), the stress acting on the measurement portion A is small. Understand. On the other hand, L1 is 12.0 mm (L1 / L2 = 0.053), 19.5 mm (L1 / L2 = 0.086), 22.0 mm (L1 / L2 = 0.097), 24.5 mm ( When L1 / L2 = 0.108), it can be seen that the stress acting on the measurement portion A is large. Therefore, when L1 / L2 is in the range of 0.06 to 0.08, it can be confirmed that the stress acting on the measuring portion A is small, and therefore, the fatigue fracture is reduced.
[0018]
Such a hydraulic coupling 11 is, for example, prepared by preparing a ring-shaped intermediate member for the hydraulic coupling main body and a ring-shaped intermediate material for the bulging portion, and then preparing the ring-shaped intermediate member for the hydraulic coupling main body. After forming a concave portion for the liquid chamber portion 12 in which L1 / L2 is in the range of 0.06 to 0.08 on the peripheral surface and the outer peripheral surface of the ring-shaped intermediate member for the bulging portion, respectively, the concave surfaces of both are formed. It can be manufactured by welding and joining together in a state where the parts face each other.
[0019]
In the hydraulic joint 11 according to the present embodiment, since L1 / L2 is set to a specific range, even if the bulging portion 11b is repeatedly bulged, a large stress is applied to both ends of the liquid chamber portion 12 in the axial direction outside. It is difficult to act, so that the occurrence of fatigue fracture is reduced. Therefore, the shaft connecting mechanism according to the present embodiment using such a hydraulic coupling 11 connects and fixes both shafts without transmitting the play of the drive shaft 13 to the driven shaft 14 for a long time, and transmits the torque. Can be done. Further, since both outer sides in the axial direction of both ends of the liquid chamber portion 12 can be made thin, it is possible to suppress an increase in weight and material cost, and to reduce the possibility of causing dimensional defects in mounting to various devices. Since the hydraulic coupling 11 according to the present embodiment is in contact with the drive shaft 13, there is an advantage that the hydraulic pressure of the hydraulic oil press-fitted into the liquid chamber 12 can be effectively used.
[0020]
FIG. 3 is a partial cross-sectional view schematically illustrating a main configuration of a shaft coupling mechanism including a hydraulic coupling according to another embodiment of the present invention. The present embodiment is different from the above-described embodiment (see FIG. 1) in that the hydraulic coupling 11 is disposed apart from the drive shaft 13. Even in the hydraulic joint 11 having such a configuration, the value obtained by dividing the distance L1 from the end face 12a of the liquid chamber 12 to the end face 11a of the hydraulic joint 12 by the axial length L2 of the liquid chamber 12 is 0. If it is set in the range of 0.06 to 0.08, the occurrence of fatigue fracture is reduced. Further, since both outer sides in the axial direction of both ends of the liquid chamber portion 12 can be made thin, it is possible to suppress an increase in weight and material cost, and to reduce the possibility of causing dimensional defects in mounting to various devices.
[0021]
In the above embodiment, the case where the hydraulic coupling 11 is provided on the drive shaft 13 serving as the first rotation shaft has been described. However, the present invention is not limited to this, and the drive shaft 13 serving as the first rotation shaft may be provided. The hydraulic joint 11 may be provided inside. In this case, if the hydraulic coupling includes a liquid chamber portion extending in the axial direction and a swelling portion that swells due to the pressure of the liquid press-fitted into the liquid chamber portion, the whole is cylindrical. The shape may be a column shape.
[0022]
【The invention's effect】
As described above, according to the hydraulic joint of the present invention, even if there are restrictions on the external dimensions, the occurrence of fatigue fracture is reduced without increasing weight or increasing material costs. In addition, according to the shaft coupling mechanism of the present invention, since the hydraulic coupling with reduced occurrence of fatigue fracture is used, power transmission without transmitting backlash of one rotating shaft to the other rotating shaft for a long period of time. It can be performed.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view schematically showing a main configuration of a shaft coupling mechanism including a hydraulic coupling according to an embodiment of the present invention.
FIG. 2 is a graph showing a relationship between an axial length of a liquid chamber and stress.
FIG. 3 is a partial cross-sectional view schematically showing a main part configuration of a shaft coupling mechanism including a hydraulic coupling according to another embodiment of the present invention.
FIG. 4 is a partial cross-sectional view schematically showing a main configuration of a shaft coupling mechanism including a conventional hydraulic coupling.
[Explanation of symbols]
11 Hydraulic fittings (hydraulic fittings)
11a End face of hydraulic joint 11b Swelling part 12 Liquid chamber part 12a End face of liquid chamber part 13 Drive shaft (first rotation axis)
14 Followed shaft (second rotating shaft)

Claims (2)

An annular liquid chamber portion extending in the axial direction, and a swelling portion swelling due to the pressure of the liquid press-fitted into the liquid chamber portion. A hydraulic coupling for connecting a first rotating shaft that is internally or externally provided in contact with or separated from the portion, and a second rotating shaft that is internally or externally separately provided from the first rotating shaft,
A value (L1 / L2) obtained by dividing the distance L1 from the end face of the hydraulic joint to the end face of the liquid chamber part by the axial length L2 of the liquid chamber part is set in the range of 0.06 to 0.08. A hydraulic joint characterized by the above-mentioned. The first rotating shaft, a second rotating shaft provided inside or outside at a distance from the first rotating shaft, and an outside or inside contacted or separated from the first rotating shaft. A shaft coupling mechanism comprising: the above-described hydraulic coupling.

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