JP3982816B2 - Spinning method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spinning method , and more particularly to an improvement in a spinning method for a cylindrical body such as a cylinder on which a sliding body such as a piston slides.
[0002]
[Prior art]
As a spinning method for a cylindrical body such as a cylinder on which a sliding body such as a piston slides on the inside, for example, as shown in FIGS. A plurality of rollers 2 that are pressed against the outer peripheral surface of the rotating cylindrical body 1 along the radial direction of the cylindrical body 1 move in the axial direction of the cylindrical body 1 to increase the thickness of the cylindrical body 1. A strategy for thinning is well known.
[0003]
At this time, a core metal 3 for lining is inserted inside the cylindrical body 1, and it is supposed that the effectiveness at the time of so-called rolling is improved by pressing the plurality of rollers 2 against the outer peripheral surface of the cylindrical body 1.
[0004]
Incidentally, a gap S of about 0.1 mm appears between the outer peripheral surface of the cored bar 3 and the inner peripheral surface of the cylindrical body 1 at this time, so that the spinning process is optimized. In addition, the cored bar 3 can be extracted from the cylindrical body 1 after the spinning process.
[0005]
Therefore, according to this well-known spinning method , the desired pressure in the cylindrical body 1 after processing is selected by appropriately selecting the pressure contact force of the tip 2a (see FIG. 4) of the roller 2 with respect to the outer peripheral surface of the cylindrical body 1. The wall thickness can be guaranteed.
[0006]
[Problems to be solved by the invention]
However, in the known spinning method described above, there is a risk that irregularities having a depth of several μm or more appear on the inner peripheral surface of the cylindrical body 1 after processing.
[0007]
That is, in the above-described spinning process, as viewed from a so-called microscope, as shown in FIG. 4, the roller 2 is placed on the inner circumferential surface of the cylindrical body 1 where the tip 2a of the roller 2 is pressed against the outer circumferential surface. The convex portion 1a is formed by the influence of the pressure contact of the tip 2a.
[0008]
And since this cylindrical part 1 rotates, this convex part 1a appears on the inner peripheral surface of the cylindrical body 1 in what is called a screw thread, and this can be seen in the cross section of the axial direction of the cylindrical body 1. Then, as conceptually shown in FIG. 5, continuous irregularities are exposed on the inner peripheral surface of the cylindrical body 1.
[0009]
By the way, considering the actual state of the spinning process, for example, the bracket 41 as the holding means 4 for holding the upper roller 2 in FIG. 3B is the holding means for holding the lower roller 2 in FIG. The mechanical strength is inferior to that of the four-bracket 42.
[0010]
From this, as indicated by arrows in FIG. 3 (A), when moving the plurality of rollers 2 pressed against the cylindrical body 1 in the axial direction of the cylindrical body 1, an imaginary line in FIG. As shown in the figure, the upper roller 2 may start to move with a so-called delay at a position away from the position before the movement by an interval indicated by a symbol W in the figure.
[0011]
Therefore, when there is a situation where the roller 2 moves with a delay, the tip 2a may pass the same locus as the tip 2a of the lower roller 2, and therefore, one locus formed by the two rollers 2, That is, the depth of the unevenness formed on the inner peripheral surface of the cylindrical body 1 is several μm or more (see the phantom diagram in FIG. 5), and the depth is several μm or less when not passing through the same locus (FIG. 5). Compared to the solid line in the figure)
[0012]
And even if this spinning processed cylindrical body 1 is, for example, a cylinder constituting a hydraulic shock absorber, the inner peripheral surface of the cylindrical body 1 is so-called rough, and is an inner sliding body, for example, a piston There is a risk that the sliding performance and the sealing performance of the piston cannot be guaranteed.
[0013]
As a result, the above-described conventional spinning method requires so-called post-processing of the inner peripheral surface of the cylindrical body 1 after wrinkling to reduce the depth of the unevenness to a few μm or less, There is a concern that it will not be possible to improve production efficiency and reduce product costs by reducing the number of processes.
[0014]
The present invention has been made in view of the above circumstances, and the object of the present invention is, for example, the slidability of a sliding body such as a piston housed inside a cylindrical body such as a cylinder, or a piston. Guaranteeing the sealability of the product By eliminating the need for post-processing, it is possible to improve production efficiency and reduce product costs by reducing the number of processes, making it ideal for improving its versatility. It is to provide a spinning method .
[0015]
[Means for Solving the Problems]
In order to achieve the above-described object, the configuration of the spinning method according to the present invention is basically based on the radial direction of the cylindrical body, which is a plurality of directions on the outer peripheral surface of the cylindrical body that rotates around the axial center line. In a spinning method in which a plurality of rollers that are pressed in contact with each other move in the axial direction of the cylindrical body to reduce the thickness of the cylindrical body, the one roller that is pressed against the outer peripheral surface of the cylindrical body from one direction is held. The mechanical strength in the means is also in a condition that is inferior to the mechanical strength in the holding means for holding another roller pressed against the outer peripheral surface of the cylindrical body from the other direction, and the movement pressed against the outer peripheral surface of the cylindrical body It is assumed that the pressure contact position of the previous one roller is different in the forward direction from the pressure contact position of the other roller that is also pressed against the outer peripheral surface of the cylindrical body.
[0016]
Therefore, by setting the position where the one roller held by the holding means inferior in mechanical strength is in pressure contact with the outer peripheral surface of the cylindrical body in advance in the forward direction , this cylindrical roller rotates. When moving while being in pressure contact, even if the movement is delayed, the trajectory of the one roller can be divided from the trajectory of the other rollers.
[0017]
At this time, since the trajectory of one roller does not coincide with the trajectory of the other roller, the concave and convex portions having a depth of several μm or more when the two trajectories coincide with each other are not formed on the inner peripheral surface of the cylindrical body. .
[0018]
As a result, the cylindrical body that has been spun by this spinning method can be, for example, a cylinder that constitutes a hydraulic shock absorber. It is easy to ensure the slidability and the sealing performance of the piston.
[0019]
More specifically, with respect to the above-described configuration, a plurality of rollers that are press-contacted to the outer peripheral surface of the cylindrical body are three rollers, and a press-contact position of the one roller to the outer peripheral surface of the cylindrical body It is assumed that the two rollers, which are the same phase, are different in the forward direction with respect to the pressure contact position on the outer peripheral surface of the cylindrical body.
[0020]
Therefore, the trajectories of the two rollers that are in phase with each other are divided, and the trajectory of one roller is divided into the trajectories of the other rollers. It becomes possible to make the depth of the unevenness to be formed as shallow as several μm or less.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiment. However, even in the spinning method according to the present invention, as shown in FIGS. 1 and 2, basically, the conventional spinning process described above is used. Similarly to the method , a plurality of rollers 2 pressed in the radial direction of the cylindrical body 1 in a plurality of directions to the outer peripheral surface of the cylindrical body 1 rotating around the axial center line are arranged in the axial direction of the cylindrical body 1. This is a measure for moving and reducing the thickness of the cylindrical body 1.
[0022]
Incidentally, a core metal 3 for lining is inserted into the inside of the cylindrical body 1 to improve the effectiveness at the time of so-called rolling by pressing a plurality of rollers 2 against the outer peripheral surface of the cylindrical body 1. An appropriate gap S appears between the outer peripheral surface 3 and the inner peripheral surface of the cylindrical body 1 to optimize the spinning processing method, and from the inside of the cylindrical body 1 after the spinning processing method. The core metal 3 can be removed.
[0023]
In the spinning method according to the present invention, the mechanical strength of the bracket 41 as the holding means 4 that holds the one roller 2 that is pressed against the outer peripheral surface of the cylindrical body 1 from one direction is the same as that of the outer periphery of the cylindrical body 1. It is assumed that the present invention is realized under a condition inferior to the mechanical strength of the bracket 42 as the holding means 4 that holds the other roller 2 pressed against the surface from other directions.
[0024]
Therefore, in the spinning method according to the present invention, the brackets 41 and 42 as the holding means 4 are the brackets 41 and 42 as the conventional holding means 4 (see the phantom diagram in FIG. 3B). The same configuration can be used, which is advantageous in that it is not necessary to newly prepare the holding means 4.
[0025]
That is, the plurality of rollers 2 are held by a so-called firmly formed bracket 43 as the integrated holding means 4 as shown by a virtual diagram in FIG. If there is no such situation, the situation that the present invention sees as a problem will not be invited.
[0026]
However, when the integrally formed bracket 43 as described above is used, the processing apparatus itself is increased in size to deteriorate the installation property and operability, and the production cost of the processing apparatus itself is increased. There is a possibility that improvement in versatility cannot be expected.
[0027]
Accordingly, in the spinning method according to the present invention, the pressure contact position of the one roller 2 held by the bracket 41 to the outer peripheral surface of the cylindrical body 1 is advanced in advance in the moving direction of the roller 2. It can be said that it is sufficient to make the phases different from each other appropriately, and it is advantageous in that the processing apparatus does not cause an unnecessarily high cost and does not deteriorate the installation property and operability.
[0028]
Next, in the spinning method according to the present invention, the pressure contact position on the outer peripheral surface of the cylindrical body 1 in the one roller 2 in a stationary state before being moved is also pressed on the outer peripheral surface of the cylindrical body 1. It is assumed that the pressure contact positions of the other rollers 2 are different from each other by an interval indicated by a symbol W in the drawing.
[0029]
At this time, the direction in which the one roller 2 is out of phase is the moving direction of the roller 2 as described above, and the interval W in which the one roller 2 is out of phase is held by the bracket 41 having poor mechanical strength. This is the interval W at which one roller 2 moves with a so-called delay when the cylindrical body 1 moves.
[0030]
Incidentally, in many cases, the interval W of different phases will be calculated by computer processing after numerical values are set, but may be realized by machine operation by a so-called skilled worker. Of course.
[0031]
As described above, in the spinning method according to the present invention, by rotating the position where one roller 2 held by the bracket 41 having poor mechanical strength is pressed against the outer peripheral surface of the cylindrical body 1 in advance, Even when one roller 2 moves with a delay when moving in the axial direction of the cylindrical body 1 while being pressed against the cylindrical body 1, the locus on the one roller 2 is different from the locus on the other rollers 2. It becomes possible to.
[0032]
At this time, the trajectory of one roller 2 and the trajectory of the other roller 2 do not coincide with each other, and therefore when the two trajectories coincide with each other, the depth formed on the inner peripheral surface of the cylindrical body 1 is several μm or more. The unevenness of the thickness is not exposed.
[0033]
As a result, for the cylindrical body 1 that has been spun by this spinning process , for example, a cylinder that constitutes a hydraulic shock absorber, the inner peripheral surface can be prevented from becoming so-called rough, and the inner sliding body can be, for example, It becomes easy to ensure the sliding property of the piston and the sealing property of the piston.
[0034]
At this time, in the drawing, the plurality of rollers 2 pressed against the outer peripheral surface of the cylindrical body 1 are assumed to be three rollers, and the pressure contact position of the one roller 2 with respect to the outer peripheral surface of the cylindrical body 1 is It is assumed that the two rollers which are in phase with each other are out of phase in the forward direction which is the left direction in FIG. 1 with respect to the pressure contact position on the outer peripheral surface of the cylindrical body 1 in the two rollers.
[0035]
Therefore, the trajectory of the two rollers as the other rollers 2 in phase with each other is divided, and the trajectory of one roller 2 is divided into the trajectories of the other rollers 2. It is possible to easily reduce the depth of the unevenness formed on the inner peripheral surface of the body 1 to several μm or less.
[0036]
In view of the above, the greater the number of rollers 2 that are pressed against the outer peripheral surface of the cylindrical body 1, the more the burden on the one roller 2 is reduced. Therefore, it is more advantageous for ensuring the durability of the processing apparatus. On the contrary, if the present invention intends, it is sufficient to have two or more rollers 2.
[0037]
In the above description, the out-of-phase direction of one roller 2 is the forward direction as the moving direction of the one roller 2, but from the viewpoint of not passing the same locus intended by the present invention, the out-of-phase direction described above is used. Of course , the reverse direction may be used.
[0038]
In the above description, the cylindrical body 1 is only rotated. However, as long as so-called rolling is realized, the cylindrical body 1 moves while rotating, and the roller 2 only rotates at a so-called fixed position. Of course, it may be set.
[0039]
【The invention's effect】
As described above, according to the first aspect of the present invention, the position where the one roller held by the holding means inferior in mechanical strength is pressed against the outer peripheral surface of the cylindrical body is made different in advance in the forward direction. Thus, even when one roller moves so as to be delayed when moving while being pressed against the rotating cylindrical body, the locus on the one roller can be separated from the locus on the other roller.
[0040]
At this time, since the trajectory of one roller and the trajectory of the other roller do not coincide with each other, when the trajectories of both rollers coincide, the unevenness formed on the inner peripheral surface of the cylindrical body has a depth of several μm or more. No longer formed.
[0041]
As a result, when the cylindrical body spun by this spinning method is used as a cylinder constituting a hydraulic shock absorber, for example, the inner peripheral surface can be prevented from becoming rough, and the inner sliding body, for example, a piston can be prevented. It becomes easy to ensure slidability and sealing performance in the piston.
[0042]
In the invention of claim 2, the trajectories of the two rollers, which are other rollers in the same phase, are divided, and the trajectory of one roller is divided into the trajectories of the other rollers. Therefore, the depth of the irregularities formed on the inner peripheral surface of the cylindrical body can be reduced to several μm or less.
[0043]
As a result, according to the present invention, for example, after the post-processing is not required for ensuring the slidability of the sliding body such as the piston inside the cylindrical body such as the cylinder, the production efficiency by reducing the number of processing It is optimal to expect improvement in versatility by enabling improvement in product cost and reduction in product cost.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an example embodying a spinning method according to the present invention.
FIG. 2 is a diagram showing a state of arrangement of rollers when a spinning method according to the present invention is embodied .
FIGS. 3A and 3B show an example of embodying a conventional spinning method, where FIG. 3A is a view similar to FIG. 1, and FIG. 3B is a view similar to FIG.
FIG. 4 is an enlarged view showing a state of an inner peripheral surface of a cylindrical body during a spinning method.
FIG. 5 is a diagram showing the depth of irregularities exposed on the inner peripheral surface of a cylindrical body by a spinning method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical body 2 Roller 3 Core metal 4 Holding means 41, 42, 43 Bracket S Clearance W Interval

Claims (2)

A plurality of rollers pressed in the radial direction of the cylindrical body, which is a plurality of directions, on the outer peripheral surface of the cylindrical body rotating around the axial center line moves in the axial direction of the cylindrical body to increase the thickness of the cylindrical body. In the thinning spinning method , the mechanical strength of the holding means for holding one roller pressed from one direction to the outer peripheral surface of the cylindrical body is the same as that of the other roller pressed from the other direction to the outer peripheral surface of the cylindrical body. The pressure contact position of one roller before the movement, which is in pressure contact with the outer peripheral surface of the cylindrical body, is in a condition inferior to the mechanical strength of the holding means for holding, and the pressure contact of another roller which is also in pressure contact with the outer peripheral surface of the cylindrical body A spinning method characterized by being different in phase in a forward direction with respect to a position . The plurality of rollers that are pressed against the outer peripheral surface of the cylindrical body are three rollers, and the position of the pressure contact with the outer peripheral surface of the cylindrical body in one roller is the same as that of the two rollers that are the other rollers. The spinning method according to claim 1, wherein the spinning method is different in the forward direction with respect to the pressure contact position on the outer peripheral surface .

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