Vibration isolation device, and method for manufacturing a vibration isolation device
The method of removing over-vulcanized portions in rubber elastic bodies during manufacturing ensures uniform vulcanization and improved durability and productivity in vibration isolation devices by addressing uneven vulcanization and productivity issues.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- PROSPIRA CORP
- Filing Date
- 2024-11-05
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods for manufacturing vibration isolation devices result in uneven vulcanization of rubber elastic bodies, leading to deteriorated characteristics and durability, and compromise productivity due to the need for low temperatures and extended vulcanization times to prevent over-vulcanization.
A manufacturing method involving vulcanization molding followed by a cutting process to remove over-vulcanized portions, ensuring uniform vulcanization state and properties throughout the rubber elastic body, using a bushing with a rougher cut surface than the molded surface.
The method achieves uniform vulcanization state and properties, enhancing durability and productivity by eliminating over-vulcanized areas and allowing high-temperature, short-time vulcanization, thus maintaining desired torque and spring constant.
Smart Images
Figure 2026081731000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a vibration isolation device and a method for manufacturing the vibration isolation device.
Background Art
[0002] As a method for manufacturing a vibration isolation device, for example, Patent Document 1 discloses, as a method for manufacturing an engine mount which is an example of a vibration isolation device, a method in which a sleeve (outer cylindrical member) and a core (inner cylindrical member) are set in a mold in advance, an unvulcanized rubber material is injected into the mold, and then the mold temperature is maintained at a predetermined vulcanization temperature, and after a predetermined vulcanization time has elapsed, the mold is opened for manufacturing. Since the heat during vulcanization is transmitted from the mold toward the inside, the central portion side of the rubber volume takes more time to vulcanize than the outer peripheral side. Therefore, the vulcanization time is set based on the degree of vulcanization of the central portion of the rubber volume.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, since the vulcanization time is set based on the degree of vulcanization of the central portion of the rubber volume, when the central portion is vulcanized, the outer peripheral side portions are over-vulcanized, and there is a problem that the characteristics and durability of the rubber elastic body deteriorate. Also, in order to suppress variations in characteristics and durability throughout the rubber elastic body, it is conceivable to set a low vulcanization temperature and increase the vulcanization time for vulcanization molding, but there is a problem of poor productivity.
[0005] Therefore, an object of the present invention is to provide a vibration isolation device and a method for manufacturing the vibration isolation device, in which the variation in vulcanization state and characteristics throughout the rubber elastic body is small, and which are excellent in durability and productivity. [Means for solving the problem]
[0006] To achieve the above objective, the present invention provides a vibration damping device comprising an outer cylinder member, an inner cylinder member disposed within the hollow portion of the outer cylinder member, and a rubber elastic body formed by vulcanization molding and interposed between the outer cylinder member and the inner cylinder member, wherein the rubber elastic body has a cut surface portion that is rougher than the molded surface portion that came into contact with the mold used for vulcanization molding after being cut after the vulcanization molding. [Effects of the Invention]
[0007] According to the present invention, it is possible to provide a vibration isolation device and a method for manufacturing a vibration isolation device that exhibits low variation in vulcanization state and properties throughout the rubber elastic body, resulting in excellent durability and productivity. Other problems, configurations, and effects will be clarified by the following description of embodiments. [Brief explanation of the drawing]
[0008] [Figure 1] This is a cross-sectional view showing a vibration isolation device according to an embodiment. [Figure 2] This figure shows a method for manufacturing a vibration isolation device according to an embodiment. [Figure 3] This figure shows the relationship between vulcanization time and torque. [Figure 4] This figure shows the relationship between the temperature transfer time during vulcanization and the distance from the mold surface. [Figure 5] This figure shows the difference in heat transfer time between the mold surface and the deepest part. [Figure 6] This is a cross-sectional view showing an uncut bushing. [Figure 7] This is a diagram showing the cutting process. [Figure 8A] This figure shows the relationship between the amount of material removed and the spring constant of the rubber elastic material. [Figure 8B] This is a cross-sectional view showing bushings with different amounts of material removed. [Figure 9] This figure shows a modified example of a method for manufacturing a vibration isolation device. [Modes for carrying out the invention]
[0009] Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, as an example of a vibration damping device, a bush used in the connection between the vehicle body and the engine or suspension arms will be described.
[0010] As shown in Figure 1, the bush 1 according to this embodiment comprises an outer cylindrical member 2, an inner cylindrical member 3 coaxially arranged within the hollow portion of the outer cylindrical member 2, and a rubber elastic body 4 interposed between the outer cylindrical member 2 and the inner cylindrical member 3 to connect them.
[0011] The inner cylinder member 3 is a cylindrical metal member located in the center of the bush 1. The inner cylinder member 3 has a hollow hole 3A that runs through it along the axial direction, and is fixed to the suspension arm or the like via a bolt inserted through the hollow hole 3A. Both axial ends of the inner cylinder member 3 protrude from both axial ends of the outer cylinder member 2.
[0012] The outer cylinder member 2 is a cylindrical metal member, positioned radially outward and spaced apart from the inner cylinder member 3. The outer circumferential surface 2A of the outer cylinder member 2 is the part that is held by a bracket or the like on the vehicle body side.
[0013] The rubber elastic body 4 is interposed between the outer cylinder member 2 and the inner cylinder member 3, elastically connecting the outer cylinder member 2 and the inner cylinder member 3. Annular recesses 4A are formed on both axial ends of the rubber elastic body 4, coaxially arranged with the outer cylinder member 2 and the inner cylinder member 3. The annular recesses 4A are continuous along the entire length in the circumferential direction.
[0014] As shown in Fig. 2, the manufacturing method of the bush 1 has a molding process S1 and a cutting process S2. In the molding process S1, the outer cylinder member 2 and the inner cylinder member 3 are set in a mold for vulcanization molding, an unvulcanized rubber material (hereinafter referred to as unvulcanized rubber) is injected into the mold, and the mold is heated to vulcanize the unvulcanized rubber to form a rubber elastic body 4. In the cutting process S2, cutting is performed on the surface of the rubber elastic body 4 of the molded product removed from the mold to cut the over-vulcanized portion.
[0015] Fig. 3 is a graph showing the time change of torque (torsional torque) when unvulcanized rubber is vulcanized at a predetermined temperature. As shown in Fig. 3, for the unvulcanized rubber, as vulcanization progresses, the torque (torsional torque) increases, the torque reaches a peak after a predetermined time has elapsed, and then the torque begins to decrease if heating continues. Therefore, in vulcanization molding, it is desirable to set the heating time (vulcanization time) to the time when the torque reaches the peak.
[0016] Also, in vulcanization molding, as shown in Fig. 4, the temperature transfer time during vulcanization is proportional to the distance from the mold surface. In the molding process S1, since heating is performed from the mold side to the unvulcanized rubber, there is a difference in the heat transfer time between the part in contact with the mold surface and the part away from the mold surface (the part on the center side of the mold). For example, as shown in Fig. 5, there is a time difference Lt in the time it takes for the unvulcanized rubber to reach the temperature at which it is heated between the part in contact with the mold surface (dashed line) and the part farthest from the mold surface (the deepest part: solid line).
[0017] In this case, assuming that the graph shown in Fig. 3 shows the time change of the torque of the part in contact with the mold surface, the torque of the deepest part will reach the peak Lt time after the torque of the part in contact with the mold surface reaches the peak. Therefore, the vulcanization time is set to the time T2 when the torque of the deepest part reaches the peak, that is, the time T2 obtained by adding the time Lt to the time T1 when the torque of the part in contact with the mold surface reaches the peak. In this case, for the part in contact with the mold surface that reaches the peak earlier than the set time T2 by the time Lt, there is an over-vulcanized portion on the surface of the formed rubber elastic body 4, and the torque of the over-vulcanized portion is decreasing.
[0018] Therefore, the molded product molded in the molding step S1 is subjected to cutting on the surface of the rubber elastic body 4 in the cutting step S2, and the over-vulcanized portion is removed.
[0019] In the molding step S1, the outer cylindrical member 2 and the inner cylindrical member 3 are arranged in a rubber elastic body molding die for molding the rubber elastic body 4, molten rubber is injected between the outer cylindrical member 2 and the inner cylindrical member 3, and after maintaining at a predetermined temperature for a predetermined time, it is cooled to mold an uncut bush (hereinafter referred to as an uncut bush) 1A. The uncut bush 1A molded by the molding step S1, as shown in FIG. 6 for example, does not have annular recesses 4A provided at both axial end faces of the rubber elastic body 4.
[0020] In the cutting step S2, cutting is performed on both axial end faces of the rubber elastic body 4 of the uncut bush 1A to remove the over-vulcanized portion and form the annular recess 4A. In the cutting step S2, as shown in FIG. 7, first, the uncut bush 1A is held by the chuck 5 of the fixing jig in a posture where the axes of its outer cylindrical member 2 and inner cylindrical member 3 face in the vertical direction.
[0021] Next, a tool 6 provided with a cutting edge 6A for forming the annular recess 4A is rotated around the axes of the outer cylindrical member 2 and the inner cylindrical member 3 and lowered from above the uncut bush 1A held by the chuck 5 to remove the surface of the rubber elastic body 4. After removing one end face of the rubber elastic body 4 of the uncut bush 1A in the axial direction, the up-and-down orientation is changed and it is held by the chuck 5 of the fixing jig to remove the other end face in the axial direction.
[0022] At this time, the over-vulcanized portions present on the surface portions of both axial end faces of the rubber elastic body 4 that have become over-vulcanized in the molding step S1 are also cut and removed. For this reason, the rubber elastic body 4 of the uncut bush 1A has a shape such that the desired shape of the rubber elastic body 4 of the completed bush 1 can be ensured even after removing the over-vulcanized portion, as shown in FIG. 6.
[0023] The cutting blade 6A is formed to conform to the desired shape of the rubber elastic body 4, and by advancing the tool 6 in the axial direction, the over-vulcanized portion is removed and the rubber elastic body 4 is cut to the desired shape. During cutting, the surface of the rubber elastic body 4 that does not come into contact with the cutting blade 6A remains uncut, retaining the molded surface portion that was formed in contact with the mold during vulcanization molding. As shown in Figure 1, the surface of the rubber elastic body 4 of the completed bush 1 after the cutting process S2 is finished has the cut surface portion 4B exposed, and the cut surface portion 4B has a rougher surface than the molded surface portion.
[0024] According to the bush 1 and the method for manufacturing the bush 1 of the present invention, the rubber elastic body 4 interposed between the outer cylindrical member 2 and the inner cylindrical member 3 is formed by removing the over-vulcanized portion during the vulcanization molding process S1, so the bush 1 does not contain any over-vulcanized portions. Therefore, the vulcanization state of the entire rubber elastic body 4 of the bush 1 is uniform.
[0025] Over-vulcanized areas exhibit lower torque than properly molded and vulcanized areas, and also harden, making them more prone to cracking. Therefore, bushing 1, which does not include over-vulcanized areas, possesses the characteristic of achieving the set torque as a whole rubber elastic body 4, and also exhibits superior durability.
[0026] Furthermore, since the over-vulcanized portion is removed after vulcanization molding, there is no need to perform vulcanization molding at a low temperature for a long time to avoid over-vulcanization. For example, when heating at a high temperature, vulcanization molding that would normally take about 5 minutes may have to be performed for about 30 minutes if the vulcanization temperature is set low to avoid over-vulcanization, due to factors such as the longer time it takes for the material to heat up.
[0027] Therefore, removing the over-vulcanized portion by cutting for about 2 minutes after molding at a high temperature for 5 minutes allows for a shorter manufacturing time than vulcanizing at a low temperature for a long time to prevent over-vulcanization. In other words, since the bush 1 of this embodiment can be vulcanized at a high temperature for a short time, the manufacturing time can be shortened even if the cutting process S2 is performed after the molding process S1. Therefore, it has excellent productivity.
[0028] Furthermore, as shown in the graph in Figure 8A, there is a relationship between the amount of material removed from the rubber elastic body 4 in the cutting process S2 after vulcanization molding and the spring constant of the cut rubber elastic body 4, where the spring constant decreases as the amount of material removed increases. Therefore, when removing the over-vulcanized portion by cutting, it is possible to adjust the characteristics of the bush 1 by adjusting the amount of material removed, as shown in Figure 8B.
[0029] In the above embodiment, an example was described in which, as a method for manufacturing the bush 1, unvulcanized rubber injected between the outer cylinder member 2 and the inner cylinder member 3 is vulcanized to form a rubber elastic body 4, and then the surface of the rubber elastic body 4 is machined to remove the over-vulcanized portion. However, the method is not limited to this. For example, as shown in Figure 9, first, in the molding step S1, a cylindrical rubber elastic body (hereinafter referred to as an uncut rubber elastic body) 40 is molded using a mold for vulcanizing the rubber elastic body 4, and in the cutting step S2, the uncut rubber elastic body 40 is machined to form a rubber elastic body 4 of the desired shape. After that, the rubber elastic body 4 after the cutting step S2 is press-fitted into the outer cylinder member 2 on which adhesive has been applied to the inner circumferential surface, and the inner cylinder member 3 on which adhesive has been applied to the outer circumferential surface is press-fitted into the hollow hole 4C that penetrates the rubber elastic body 4 along the axial direction to manufacture the bush 1.
[0030] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. All technical matters included in the technical concept described in the claims are subject to the present invention. The embodiments described above are preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed herein, and these are included in the technical scope described in the appended claims. [Explanation of symbols]
[0031] 1 Bush 1A Uncut bushing 2. Outer cylinder member 2A Outer surface 3. Inner cylinder member 3A hollow hole 4. Rubber elastic body 4A Annular recess 4B Cutting surface area 4C hollow hole 5 zippers 6 Tools 6A cutting blade 40 Uncut rubber elastic body S1 Molding process S2 Cutting process
Claims
1. Outer cylinder member and An inner cylinder member disposed within the hollow portion of the outer cylinder member, The system comprises a rubber elastic body formed by vulcanization molding and interposed between the outer cylindrical member and the inner cylindrical member, The vibration isolation device is characterized in that the rubber elastic body has a cut surface portion that is rougher than the molded surface portion that was cut after vulcanization molding and came into contact with the mold used for vulcanization molding.
2. Outer cylinder member and An inner cylinder member disposed within the hollow portion of the outer cylinder member, A method for manufacturing a vibration damping device comprising a rubber elastic body that is vulcanized and interposed between the outer cylindrical member and the inner cylindrical member, A molding step in which the rubber elastic body is formed by vulcanization molding, A method for manufacturing a vibration damping device, characterized by comprising a cutting step of cutting off the over-vulcanized portion after the molding step.
3. A method for manufacturing a vibration isolation device according to claim 2, A method for manufacturing a vibration damping device, characterized in that the rubber elastic body is joined to the outer cylindrical member and the inner cylindrical member by the molding process.
4. A method for manufacturing a vibration isolation device according to claim 2, A method for manufacturing a vibration damping device, characterized in that the rubber elastic body is joined to the outer cylinder member and the inner cylinder member after the cutting process.