JPH0314986A - Clamp structure of hydraulic piping - Google Patents

Abstract

PURPOSE:To enable sure clamping with a specified bolt axial force by providing a lower clamp between an upper clamp and a screw seat, making the thickness of recessed central part between the upper and lower clamps a specified size, and forming a space between the lower face of the lower clamp and the upper face of screw seat. CONSTITUTION:There are provided an upper clamp 7 having a semicircular recessed face for retaining a pipe 1, screw seat fixed to a frame body 6, and bolt 4. The thickness sizes TU, TL of clamps 7, 8 are set so that slight gap 9 is formed in fastening the pipe 1 by means of the bolt 4. A space 10 having a size to be set by the distance between bolts 4 and the like is provided so that the clamp 8 can be resiliently deformed between the lower clamp 8 and the screw seat 3. A gap Gs is provided so that close contact is prevented upon resilient deformation of clamps 7, 8. Consequently, sure clamping can be attained without generation of scrubbing or cracking.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a clamp structure for hydraulic piping in a hydraulic working machine, and in particular, the present invention relates to a clamping structure for hydraulic piping in a hydraulic working machine, and in particular, the present invention relates to a clamp structure for hydraulic piping in a hydraulic working machine, and in particular, in a hydraulic working machine such as a hydraulic excavator or a self-propelled crane. This invention relates to a clamp structure suitable for hydraulic piping that is under high pressure and is subject to severe vibration.

[Conventional technology]

Conventionally, the hydraulic piping of hydraulic working machines such as hydraulic excavators and self-propelled cranes that use high-pressure oil and are subject to severe vibrations during operation have been exposed to severe vibrations to prevent accidents due to pipe rubbing or cracks. There is a need for a clamp structure that can withstand this and securely fix the pipe. The conventional clamp structure will be explained with reference to Figs. 3 to 5. In the figure 1
Reference numeral 2 indicates a pipe to be clamped, and 2 indicates an upper clamp having a substantially semicircular concave surface 2a that presses the upper half of the pipe 1. The concave surface 2a has a diameter slightly larger than the outer diameter of the pipe 1.

Holes 2b for bolts 4 for fixing the tube 1 are bored on both sides of the concave surface 2a. 3 is a screw seat that faces the upper clamp 2 via the pipe 1 and is fixed to the frame body 6 (for example, the boom, arm, etc. of a hydraulic excavator) by welding or the like, and the screw seat 3 has a screw hole 3b for the bolt 4. is provided. Further, the lower surface 2C of the upper clamp 2 and the upper surface 3a of the screw seat 3 are spaced apart from each other by GL. It is separated by 5 is the washer for bolt 4. When the bolt 4 is screwed in in the clamp ellipse position, the tube 1 is tightened as the axial force of the bolt 4 increases, and when the predetermined axial force is reached, the tube 1 is screwed into the concave surface of the upper clamp 2.
A and the upper surface 3a of the screw seat 3 are clamped to that part by the frictional force.

[Effect]

With the above configuration, when the bolt is screwed into the screw seat, the upper end, lower end, and surrounding areas of the pipe are pressed and high contact pressure is created, causing the pipe to deform in the flat direction.At the same time, however, the upper clamp A semicircular concave surface is elastically deformed along the outer peripheral surface of the tube with the upper end as a fulcrum, and the lower clamp has fulcrums near both ends of the space formed between the lower surface of the lower clamp and the upper surface of the screw seat, The central part of the concave surface that contacts the lower end of the tube is pressed, and the semicircular concave surface is elastically deformed along the outer circumferential surface of the tube. Here, when the bolt is screwed in, during the above elastic deformation of the upper and lower clamps, the gap between the relative surfaces of the upper and lower clamps, excluding the concave surfaces, is so small that they do not come into close contact. The play between the bolt and the hole for the bolt prevents it from being screwed in in an inclined position, thereby preventing bending stress from occurring in the bolt. Also,
The above elastic deformation of the upper and lower clamps means that when the bolt is tightened to a predetermined axial force, the difference between the upper and lower ends of the pipe and their surrounding areas and the center of the concave surface of the upper and lower clamps is A small gap is formed in the tube, and at the same time, a plurality of contact surfaces are formed on both sides of the gap, where the outer circumferential surface of the tube contacts the concave surfaces of the upper and lower clamps. By receiving the axial force during bolt tightening on these multiple contact surfaces, the tube is prevented from forming stress concentration areas due to local deformation, and the contact stress with the outer circumferential surface of the tube is reduced, resulting in stable friction. This will maintain the force, allowing you to securely clamp the tube. [Example] An example of the present invention will be described with reference to FIGS. 1 and 2. In the drawings, the same reference numerals as in FIGS. 3 to 5 indicate the same things. 7 is a semicircular concave surface 7 that presses the upper half of the tube 1
The concave surface 7a of the upper clamp has a diameter slightly larger than the outer diameter of the tube 1. 8 is upper clamp 7
and the screw seat 3. The lower clamp 8 has a semicircular concave surface 8a that receives the lower half circumference of the pipe 1.
A hole 8b for the bolt 4 is bored on both sides of the concave surface 8a. Like the concave surface 7a, the concave surface 8a has a diameter slightly larger than the outer diameter of the tube 1. The thickness dimension Tυ of the upper clamp 7 at the center of the four faces 7a that contacts the upper end 1a of the tube 1, and the thickness Tυ of the lower clamp 8 at the center of the concave surface 8a that contacts the lower end 1b of the tube 1. ．． This means that when the tube 1 is tightened with the bolt 4, the concave surface 7a8a is elastically deformed along the outer peripheral surface of the tube 1, and the center portion 7c (not shown) of the concave surface 7a, the center portion 8C of the concave surface 8a, and their The dimensions are set to form a slight gap 9 around the periphery. Reference numeral 10 denotes a space formed between the lower surface of the lower clamp 8 and the upper surface of the screw seat 3, and the space 10 has dimensions of width Lxi and length H so that the lower clamp 8 can be elastically deformed. The dimensions are determined by the distance between the bolts 4, the axial force, the dimensions and material of the lower clamp 8, etc. Gs is a gap between the opposing surfaces of the upper clamp 7 and the lower clamp 8, excluding the concave surfaces 7a and 8a, and is set to such a size that the upper clamp 7 and the lower clamp 8 do not come into close contact when they are elastically deformed.

In the above configuration, when the bolt 4 is screwed into the screw seat 3, the upper end 1a of the tube 1 is pressed by the upper clamp 7, and at the same time, the lower end 1b of the tube 1 presses the lower clamp 8. For this reason, the upper end 1a, the lower end 1b, and their surrounding areas are deformed by high contact pressure. When the tube 1 is tightened until the axial force of the bolt 4 reaches a predetermined axial force as described above, the concave surfaces 7a and 8a are elastically deformed along the outer peripheral surface of the tube 1, and the concave surface 7a , 8a, that is, the upper end 1a, the lower end 1b of the tube 1, and their surroundings are designed to form a slight gap 9.
The upper clamp 7 is elastically deformed with the upper end 1a as a fulcrum, and the lower clamp 8 is elastically deformed with the center of the concave surface 8a being pressed around both ends of the width L of the space 10 as fulcrums.

A gap 9 is formed by the elastic deformation of the upper clamp 7 and the lower clamp 8, and at the same time, a plurality of contact surfaces 11 are formed on both sides of the gap 9, where the outer circumferential surface of the tube 1 and the concave surfaces 7a, 8a come into contact almost symmetrically. The positions on the pipe 1 that receive the tightening force from the bolts 1-4 are the upper end 1a and the lower end 1a of the pipe 1.
b and their periphery to a plurality of contact surfaces 11. At the contact surface 11, the tightening force of the bolt 4 is received over a much larger area than in the past, so the contact stress is reduced.
This eliminates the formation of stress concentration areas due to local deformation of the tube 1, which occurred at the lower end 1b and the like. As a result, a stable frictional force is obtained between the tube 1 and the tube 1, making it possible to securely clamp the tube 1. On the other hand, when the bolt 4 is screwed in, the gap G3 between the opposing surfaces of the upper clamp 7 and the lower clamp 8 is
The bolt 4 is set to such a small size that it does not come into close contact with the upper clamp 7 when it is elastically deformed.
Due to the play between the bolt 4 and the hole 7b, the bolt 4 will not be screwed in in an inclined state, and bending stress will not be applied to the bolt 4, and the bolt 4 will not loosen due to vibrations of the work equipment, etc. It becomes possible to reliably tighten the pipe 1 with a specified axial force. [Effects of the Invention] Since the present invention is configured as described above, the hydraulic piping of a hydraulic working machine that uses high-pressure oil and is subjected to severe vibration during operation can be prevented from rubbing or cracking. This has the effect of being able to reliably clamp the bolt with a predetermined axial force without causing any damage.

[Brief explanation of the drawing]

Fig. 1 is a front view showing one embodiment of the clamp structure for hydraulic piping of the present invention, and Fig. 2 is an explanatory diagram of the state of elastic deformation of the clamp during bolt tightening. Figure 3 is a front view showing an example of a conventional clamp structure for hydraulic piping, and Figure 4 is the IV of Figure 3.
- IV arrow view, Figure 5 is an explanatory diagram of the state of deformation of the pipe during conventional bolt tightening.

Claims (1)

[Claims] 1. A semicircular concave surface with a diameter slightly larger than the outer diameter of the pipe that holds the upper half of the pipe of the hydraulic piping is formed, and holes for bolts for fixing the pipe are bored on both sides of the concave surface. A hydraulic pipe comprising a clamp, a screw seat that faces the upper clamp via the pipe and is fixed to a frame body having screw holes for bolts for fixing the pipe, and a plurality of bolts for fixing the pipe. In the clamp structure, a semicircular concave surface having a diameter slightly larger than the outer diameter of the tube that receives the lower half circumference of the tube is formed between the upper clamp and the screw seat, and on both sides of the concave surface there are formed a semicircular concave surface for the bolt. A lower clamp with a hole is provided, and the thickness of the central part of the concave surfaces of the lower clamp and the upper clamp is such that when the tube is tightened with the bolt, each of the concave surfaces is elastically deformed along the outer peripheral surface of the tube. The dimensions are such that a slight gap is formed in the center of the concave surface and its periphery, and the elastically deformable space is formed between the lower surface of the lower clamp and the upper surface of the screw seat, and the upper clamp and the lower clamp are A clamping structure for hydraulic piping, characterized in that a gap is formed between opposing surfaces other than the concave surface to a degree that they do not come into close contact during the elastic deformation.