JPH0233456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an endless belt hoop that improves the thickness accuracy of each belt hoop of a metal multilayer belt, and particularly relates to a method of manufacturing an endless belt hoop that improves the thickness accuracy of each belt hoop of a metal multilayer belt, and particularly relates to a method of manufacturing an endless belt hoop by welding maraging steel of a material strip into an endless shape. After that, annealing is performed to remove thermal distortion during welding and increase in hardness near the weld.
This prevents variations in wall thickness during subsequent processing to adjust belt circumference and thickness.

In recent years, metal endless belts have been considered as a means of power transmission for automobile engines, generators, etc., but in consideration of belt flexibility, strength, lubricity, etc., thin-walled belt hoops are combined into multiple layers. It is preferable to use a multilayer metal endless belt.

The biggest problem when putting such a thin-walled endless metal belt into practical use is that the first and second layers, n
This refers to the accuracy of the circumferential length difference and plate thickness between adjacent belt hoops, such as the layer and n+1 layer. If the difference in circumference is too large or too small, a difference will occur in the stress applied to the belt in each layer, and the strength of the belt will decrease. In extreme cases, even assembly as a multiple belt becomes difficult. For calculation, the difference in circumferential length between each layer is required to be 2πt (t is the thickness of each belt), and the accuracy is, for example, △l = ±0.1 m/m for the circumferential length l = 1000 m/m.
That is, an accuracy of ±0.01% is required. Regarding the plate thickness, strict plate thickness accuracy is required because the stress applied to each belt hoop is constant.
Furthermore, in order to keep the wear caused by the friction between the hoops constant, there must be no variation in the gaps between the hoops, and therefore local irregularities and distortions become a problem.

As a conventional method developed to meet such requirements, there is a method for manufacturing a multilayer belt as shown in FIG.

In this method, as shown in FIG. 1, a material 1 for an endless metal belt is first machined into a cylindrical shape as shown in FIG. 2a by preform machining. Next, this material 1 is squeezed by a punch 3 that rotates while reciprocating in the axial direction of the mandrel 2 while being fitted onto the mandrel 2 to form a thin cylinder 1'.
is formed into. After cutting unnecessary ends of the obtained thin-walled cylinder 1', a core metal material is inserted into the center, and then the thin-walled cylinder 1' is inserted between the work roller 4 and the tension roller 6 as shown in FIG. 2c. The thickness and circumference of the belt are roughly finished by rolling it with back-up rollers 5a, 5b, and 5c (hereinafter referred to as ring roll processing), and then rolling the belt. Cut to the required width.
By this ring roll processing, a circumferential length Ln corresponding to the n-th layer of the multiple belt is sequentially formed. After combining the thus obtained metal belts 1-1, 1-2, ..., 1-n, which differ in circumferential length by approximately 2πt, into a multi-ring 6 shape, the thermal expansion is larger than that of the metal belt. The core material 7 of heat-resistant steel with a coefficient is shown in Fig. 2d.
As shown in Figure 3, the entire ring is inserted and heated, thereby plastically deforming each layer of the multi-ring at the same time and correcting it to follow the dimensions of the core metal material.Then, the entire ring is cooled and the core metal material is pulled out to form the multi-layered ring. This is to obtain a multiple endless metal belt that is in close contact with the metal.

As mentioned above, this method consists of the steps of producing each endless belt hoop, combining the resulting belt hoops into multiple layers, and correcting the dimensions at high temperature using a core metal. Needless to say, the method of simultaneously straightening multiple layers using the above-mentioned metal core is extremely effective in improving the circumferential length accuracy of the belt hoop. In addition, when performing such core metal straightening, it is desirable to take advantage of the difference in plastic deformation characteristics against heat between the core metal and the belt. Aged steel is best.

However, in the process of manufacturing a ring-shaped material by the above-mentioned tube spinning process and then finishing it into a single seamless endless belt hoop by combining heat treatment and ring roll processing, the dimensional accuracy of the product may be affected due to uneven thickness of the link-shaped material, etc. Therefore, it is difficult to control the uneven thickness, plate thickness, and circumference of the product at the same time. This process also has the drawback of high production costs due to the long time required and low material yield in belt hoop production.

Another conventional process for manufacturing such a single endless belt hoop is to cut ultra-thin maruasing steel to a predetermined thickness and length to form a belt, and then weld both ends of the belt to form a belt. There is a method of forming a hoop, and the production cost is significantly lower than the above process, but thermal distortion occurs during welding, and the increase in hardness near the welded part causes unevenness or distortion due to uneven thickness in the subsequent ring roll processing. When these belt hoops are used in multiple layers, it is impossible to avoid the problem that wear due to friction occurs concentrated in the distorted portion.

Therefore, an object of the present invention is to provide a method suitable for manufacturing each individual belt hoop constituting a multilayer endless belt made of maraging steel, in which adjacent metal endless belt hoops are brought into close contact with each other to be used as a multilayer belt. The purpose of the present invention is to provide a method for manufacturing an endless belt hoop that has low manufacturing costs and can control the plate thickness with high precision.The main purpose of this is to create a multilayer belt by bringing adjacent metal endless belt hoops into close contact with each other. In the method of manufacturing an endless belt hoop for use as a belt hoop, both ends of a maraging steel strip are welded to form a ring shape, then annealed at a temperature of 800°C or higher, and then ring rolled to form the belt. The present invention provides a method for manufacturing an endless belt hoop, which comprises adjusting the belt thickness and circumference while reducing the wall thickness, and further performing solution treatment and aging treatment.

Next, embodiments embodying the present invention will be described in detail with reference to the accompanying drawings starting from FIG.
FIG. 3 is a process diagram showing the manufacturing process of a belt hoop according to an embodiment of the present invention.

As shown in the figure, in this example, 18% Ni-based maraging steel thin plate material (cold rolled, heat treated material thickness, e.g., T = 0.8 mm) was formed into a predetermined width and length (e.g., width W = 20 m/m, Cut into strips with a length of 160 m/m). The thus obtained strip material is rolled into a ring shape and both ends are electron beam welded to produce a welded ring for ring roll processing. As already mentioned, the details of ring roll processing are shown in Fig. 2c.
The outline is shown below. That is, the ring-shaped member 1', in which the ends of the band-shaped materials are joined by welding as described above, is connected to the work roller 4 and the tension roller 6.
The work roller 4 is attached and stretched between the work rollers 4 and 4.
and the backup roller 5b to adjust the belt thickness and circumference. However, Fig. 2c
The ring roll processing apparatus shown in FIG. The hardness of the material in the vicinity of the welded part after welding is shown in the lower part of Fig. 4. Bitsker hardness on vertical axis
HV is plotted on the horizontal axis as the distance (m/
m), and the measurement points in the welded part are shown by black circles, and the measurement points in the base material part are shown by white circles. It is understood that the hardness reaches its peak at a location approximately 1 m/m away from the center of the welded area on either side. If subsequent ring roll processing is performed while such extreme changes in hardness are left unattended, it will cause uneven thickness, and when combined into a multilayer belt, the stress on each belt hoop will not be uniform and the belt hoop will break. or uneven wear.
Therefore, in the present invention, the weld ring is annealed to make the hardness distribution of the welded part uniform, and then ring roll processing is performed. In this example, annealing was performed at 850°C for 1 hour. The hardness distribution in the vicinity of the welded part after annealing at this time is shown in the upper part of FIG. It can be seen from this figure that the peak at a position of about 1 m/m from the center of the weld disappears due to annealing, and the hardness becomes uniform. In this example, the ring-shaped body thus obtained was subjected to ring roll processing to a thickness of 0.2 m/mm.
m, a belt hoop with a circumference of 800 m/m is formed, and 820
As a result of solution treatment at 150°C for 1 hour followed by aging treatment at 150°C for 3 hours, we succeeded in manufacturing an endless belt hoop with very little variation in wall thickness and a smooth welded area. The solution treatment mentioned above is generally 800 to 900℃ for maraging steel, and the aging treatment is 450 to 550℃.
Performed at °C.

As for the welding method, electron beam welding and plasma arc welding are preferable because they cause relatively little variation in the thickness of the welded metal part compared to the base metal, but TIG welding and the like are also possible.

FIG. 6 shows a cross-sectional view of the vicinity of the welded portion after ring roll processing. 8 is the outer surface of the belt, 9 is the inner surface, the figure a shows the as-welded state, and 6 shows the belt at 750℃ x 1.
c is the case where ring roll processing was performed after annealing at 850°C for 1 hour. It is understood that as the value increases, the amount of uneven thickness decreases. Here, it is desirable that the annealing temperature is 800°C or higher.
FIG. 5 shows experimental results of thickness deviation after ring roll processing at various annealing temperatures. This shows that the uneven thickness decreases as the annealing temperature increases up to 800°C, and reaches an equilibrium state when it exceeds 800°C.

As described above, the present invention relates to a method for manufacturing an endless belt hoop for use as a multilayer belt by closely adhering adjacent metal endless belt hoops, in which both ends of a maraging steel strip are welded to form an endless ring. After that, it is annealed at a temperature of 800℃ or higher, and then subjected to ring roll processing to reduce the belt wall thickness and adjust the belt thickness and circumference, and then subjected to solution treatment and aging treatment. Since this is a manufacturing method of an endless belt hoop, the hardness distribution generated in the welded part is uniform (fourth
(Fig. 6), the uneven thickness, unevenness, and distortion of the welded part due to subsequent ring roll processing disappear (Fig. 6), and when performing ring roll processing after heat treatment after spinning as in the past (thickness unevenness: 10 to 15 μm). ), it is ideal for multi-layer belts as it can keep the thickness deviation to 6μm or less, and the material yield is significantly improved compared to the conventional method mentioned above, and the production cost is reduced by shortening the process. It is.

[Brief explanation of drawings]

Fig. 1 is a process diagram of the forming process of a metal endless belt in which the interlayer gap between adjacent belt hoops is substantially 0, Fig. 2a is a side sectional view of the raw material supplied to the same process, and Fig. 2b is the same method. c is a schematic side view showing the state of ring roll processing of each single belt, and d shows the state in which the core metal material is fitted into the multiple belts. A side sectional view, FIG. 3 is a process diagram showing a manufacturing process of a belt hoop according to an embodiment of the present invention,
FIG. 4 is a graph showing the hardness of the material in the vicinity of the welded part after welding, the upper row shows the state after annealing at 850°C, and the lower row shows the state without annealing. Furthermore, Fig. 5 is a graph showing the experimental results of the thickness deviation after ring roll processing for various annealing temperatures, and Fig. 6 a, b, and c are cross-sectional views of the vicinity of the welded portion after ring roll processing, respectively. Figure a shows the as-welded condition, figure b shows the case after annealing at 700°C and ring roll processing, and figure c shows the welded condition.
shows the case of ring roll processing after annealing at 850℃. Explanation of symbols 6... Metal endless belt, 1-
1, 1-2,..., 1-n... Single belt hoop in each layer, 7... Core metal material.

Claims (1)

[Claims] 1. In a method for manufacturing an endless belt hoop for use as a multilayer belt by bringing adjacent metal endless belt hoops into close contact with each other, after welding both ends of a maraging steel strip material to form an endless ring shape, The endless ring is annealed at a temperature of ℃ or higher, and then the endless ring is stretched between a work roller and a tension roller, and is sandwiched between the work roller and the back-up roller to reduce the thickness of the belt. A method for manufacturing an endless belt hoop, which comprises adjusting the belt thickness and circumference while reducing the belt thickness, and further performing solution treatment and aging treatment.