Buffer device

Abstract

To provide a shock absorber that can be made more cost-effective. [Solution] A shock absorber comprising: a cylinder part containing a working fluid; a piston part inserted into the cylinder part; a rod having one end connected to the piston part and the other end exposed to the outside of the cylinder part; a mounting eye attached to the other end of the rod; and a dust cover covering the exposed portion of the rod from the cylinder part, wherein the eye body of the mounting eye has a tip member located on the other end side and an intermediate member provided between the tip member and the rod and joined to the tip member and the rod, the intermediate member having a cylindrical part, a closing part that closes one opening in the cylindrical part, and a holding part provided on the other opening side of the cylindrical part for holding the dust cover, the cylindrical part being joined to the other end of the rod, and the part of the closing part opposite to the cylindrical part being joined to the tip member.

Description

【Technical Field】 , 【0004】 , , , , , , 【0001】 The present invention relates to a shock absorber. 【Background Art】 【0002】 The shock absorber described in Patent Document 1 includes a cylinder in which a working fluid is enclosed, a piston inserted into the cylinder, a rod having one end connected to the piston and the other end extending outside the cylinder, and a mounting eye attached to the other end of the rod. The mounting eye consists of an outer eye body attached to the rod and an inner rubber bush. The eye body has an annular member forming an annular shape, a female member fixed along the radial direction of the annular member on the outer peripheral portion of the annular member, and a holding member interposed between the annular member and the female member. The holding member and the female member are fixed to the annular member by welding, so that the holding member, the female member, and the annular member are integrated. The female member of the eye body and the male portion of the rod are fitted to each other. More specifically, the male portion of the rod is inserted into the connection cylinder portion of the eye body, and the joint portion of the inner wall is pushed into the annular groove of the rod and joined by clamping the outer wall of the connection cylinder portion from the outside. Also, a dust cover is connected to the outer peripheral portion of the holding plate portion of the holding member of the eye body, and thereby the dust cover is held by the eye body. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent No. 5909358 【Summary of the Invention】<000,020><000,021>【Problems to be Solved by the Invention】<000,022><000,023><000,024><000,025>The shock absorber described in Patent Document 1 has an eye body composed of three parts: a ring-shaped member, a female-shaped member, and a retaining member. Therefore, compared to a case where the eye body is composed of two parts, material costs and component management costs increase, which may lead to higher costs. The present invention aims to provide a cushioning device that can be made more cost-effective. [Means for solving the problem] 【0005】 The present invention, completed with this objective in mind, is a shock absorber comprising: a cylinder portion in which a working fluid is sealed; a piston portion inserted into the cylinder portion; a rod having one end connected to the piston portion and the other end exposed to the outside of the cylinder portion; a mounting eye attached to the other end of the rod; and a dust cover covering the portion of the rod exposed from the cylinder portion. The eye body of the mounting eye has a tip member positioned closest to the other end and an intermediate member provided between the tip member and the rod and joined to the tip member and the rod. The intermediate member has a cylindrical portion, a closing portion that closes one opening in the cylindrical portion, and a holding portion provided on the other opening side of the cylindrical portion for holding the dust cover. The cylindrical portion is joined to the other end of the rod, and the portion of the closing portion opposite to the cylindrical portion is joined to the tip member. [Effects of the Invention] 【0006】 According to the present invention, it is possible to provide a cushioning device that can be made inexpensive. [Brief explanation of the drawing] 【0007】 [Figure 1] This figure shows an example of a schematic configuration of a shock absorber according to the embodiment. [Figure 2] This is a diagram showing an example of the general configuration of the eye unit. [Figure 3] This figure shows an example of the crimping process using a crimping device. [Figure 4]This figure shows an example of a cross-section of section IV-IV in Figure 3. [Modes for carrying out the invention] 【0008】 Embodiments of the present invention will be described in detail below with reference to the attached drawings. Figure 1 is a diagram showing an example of the schematic configuration of the buffer device 1 according to this embodiment. Figure 2 shows an example of the schematic configuration of the eye unit 101. The shock absorber 1 is a hydraulic shock absorber used in four-wheeled vehicles such as passenger cars, and as shown in Figure 1, it comprises a cylinder section 10, a rod 20, a piston section 30, a bottom section 40, and a dust cover 50. 【0009】 In the following, the axial direction of the rod 20 may be simply referred to as the "axial direction." Also, the first axial side (lower side in Figure 1) and the second axial side (upper side in Figure 1) may be simply referred to as the "first side" and the "second side," respectively. Furthermore, the direction intersecting the axial direction (for example, the orthogonal direction) will be referred to as the "radial direction." In the radial direction, the side of the cylinder 11 that will be described later may be simply referred to as the "inside," and the side away from the centerline may be simply referred to as the "outside." Furthermore, the direction around the axis of the rod 20 may be simply referred to as the "circumferential direction." 【0010】 (Cylinder section 10) The cylinder section 10 comprises a cylinder 11 for containing oil, an outer cylinder 12 provided on the outside of the cylinder 11, a bottom cover 13 that closes the first end of the outer cylinder 12, and a mounting eye 14 fixed to the first side surface of the bottom cover 13 by welding or the like. The cylinder section 10 forms a reservoir chamber R with the outer circumferential surface of the cylinder 11 and the inner circumferential surface of the outer cylinder 12. The cylinder section 10 also comprises a rod guide section 15 that movably supports the rod 20, and an oil seal 16 that prevents oil leakage from the cylinder section 10 and the entry of foreign matter into the cylinder section 10. The cylinder section 10 also comprises a rebound seat 17 and a rebound rubber 18. 【0011】 (Rod 20) The rod 20 is a rod-shaped member that extends long in the axial direction. The rod 20 holds the piston portion 30 at its lower end 21, which is the first end. A rebound seat 17 is also fixed to the rod 20 by welding or the like. The rod 20 has a groove 24 formed around its entire circumference at the upper end 22, which is the second end, recessed from the outer circumferential surface 23. A mounting eye 100 is joined to the groove 24. The mounting eye 100 and the connection between the mounting eye 100 and the rod 20 will be described in detail later. 【0012】 (Piston section 30) The piston section 30 includes a piston 31, a valve group 32 that closes the first end of some of the oil passages among the multiple oil passages formed in the piston 31, and a valve group 33 that closes the second end of some of the oil passages formed in the piston 31. The piston section 30 is fixed to the rod 20 with a nut 35. 【0013】 (Bottom section 40) As shown in Figure 1, the bottom portion 40 includes a valve body 41 having a plurality of oil passages that penetrate in the axial direction, a valve 42 provided on the first side of the valve body 41, and a valve 43 provided on the second side of the valve body 41. The valve body 41 at the bottom portion 40 separates the oil chamber and the reservoir chamber R within the cylinder 11. 【0014】 (Dust cover 50) The dust cover 50 is a cylindrical component. The dust cover 50 is joined to the mounting eye 100 and covers the portion of the rod 20 exposed from the cylinder portion 10 and the second end of the cylinder portion 10. The dust cover 50 prevents foreign matter such as dust from adhering to the rod 20 and prevents foreign matter from entering the cylinder portion 10. 【0015】 (Mounting eye 100) The mounting eye 100 has an outer eye body 101 that is attached to the rod 20 and an inner rubber bushing 102. The eye body 101 has a tip member 110 disposed on the second side most in the buffer device 1, and an intermediate member 120 provided between the tip member 110 and the rod 20 and joined to the rod 20 and the eye body 101. 【0016】 The tip member 110 is a cylindrical member whose direction intersecting the axial direction (for example, the direction perpendicular to the paper surface of FIGS. 1 and 2) is the direction of the center line. It can be exemplified that the outer diameter of the tip member 110 and the size in the direction of the center line are not more than the inner diameter of the dust cover 50. 【0017】 The intermediate member 120 has a cylindrical portion 130, a closing portion 140 that closes the opening on the second side of the cylindrical portion 130, and a disk-shaped portion 145 provided on the opening side on the first side of the cylindrical portion 130 and protruding outward from the outer peripheral surface of the cylindrical portion 130. The intermediate member 120 is caulked to the upper end portion 22 of the rod 20 by subjecting the cylindrical portion 130 to plastic working under pressure from the outside. It can be exemplified that the intermediate member 120 is formed by subjecting a thin metal plate to press working. 【0018】 The closing portion 140 is a cylindrical portion, and the outer peripheral portion at the end on the second side is welded to the end on the first side of the tip member 110. It can be exemplified that the end face on the first side is in contact with the end face on the second side of the rod 20, but they do not necessarily have to be in contact. 【0019】 The diameter of the outer peripheral portion of the disk-shaped portion 145 is larger than the outer diameter of the outer cylinder 12 of the cylinder portion 10. The end portion on the second side of the dust cover 50 is joined to the disk-shaped portion 145. The method of joining the dust cover 50 to the disk-shaped portion 145 is not particularly limited. For example, the dust cover 50 may be caulked to the disk-shaped portion 145, or the dust cover 50 and the disk-shaped portion 145 may be welded. 【0020】 Before plastic deformation, the cylindrical portion 130 is cylindrical in shape, with an inner diameter larger than the diameter of the outer surface 23 of the rod 20. The cylindrical portion 130 is then joined to the rod 20 by being pushed into a groove 24 formed in the rod 20 through plastic deformation of its axial center. 【0021】 More specifically, the cylindrical portion 130 has a joint portion 132 that protrudes inward from the inner circumferential surface 131 and is pushed into a groove 24 formed in the rod 20. The cylindrical portion 130 is plastically deformed so that the innermost surface 133 of the joint portion 132 contacts the bottom surface 241 of the groove 24 in the rod 20. Furthermore, the cylindrical portion 130 has a pressing portion 135 that protrudes second to the joint portion 132 and inward from the inner circumferential surface 131, and is pressed against the outer circumferential surface 23 of the rod 20. The joint portion 132 and the pressing portion 135 are provided continuously in the axial direction. 【0022】 The following describes how to crimp the mounting eye 100 onto the rod 20. Figure 3 shows an example of the crimping process using a crimping device. Figure 4 shows an example of a cross-section of section IV-IV in Figure 3. Figure 4 also shows an example of a cross-section of punch 150. For example, the eye body 101 of the mounting eye 100 is crimped to the rod 20 using the crimping apparatus described in Patent Document 1. 【0023】 More specifically, the eye body 101 is supported on the support base of the crimping device, and the upper end 22 (see Figure 2) of the rod 20 is fitted into the cylindrical portion 130 of the intermediate member 120 of the eye body 101, after which the lower end 21 of the rod 20 is supported by the rod support mechanism. As a result, the eye body 101 and the rod 20 are aligned along the axial direction with their centerlines aligned. In this state, when the multiple crimping cylinders are driven, they are precisely synchronized by the link member and synchronization slider, and as shown in Figure 3, multiple (six in Figure 3) punches 150 arranged in the circumferential direction advance toward the eye body 101 (in other words, toward the inside). Then, the multiple punches 150 simultaneously contact the cylindrical portion 130 of the eye body 101 from the outside with their tip crimping portions 175, pushing the contact point inward, performing a so-called shrinking process. As a result, multiple joint portions 132 (see Figure 2) that fit into the groove 24 of the rod 20 and pressing portions 135 (see Figure 2) that are pressed against the outer circumferential surface 23 of the rod 20 are formed at multiple positions on the eye body 101 that are equally spaced in the circumferential direction, thereby fixing the eye body 101 to the rod 20. Furthermore, in the punch 150 shown in Figure 4, the central front portion 165 that forms the pressing portion 135 is offset outward overall more than the tip surface portion 160 that forms the joint portion 132, so the amount of pressure applied by the pressing portion 135 is smaller compared to that applied by the joint portion 132. 【0024】 (Method for manufacturing the buffer device 1) The manufacturing method for the buffer device 1 can be exemplified as follows: After attaching the mounting eye 100 to the second end of the rod 20, the oil seal 16, rod guide section 15, rebound rubber 18, and rebound seat 17 are assembled in order from the first end of the rod 20, and the rebound seat 17 is fixed to the rod 20. Then, the piston section 30 is assembled from the first end of the rod 20 and fixed with a nut 35. The rod assembly is assembled in this way. 【0025】 Meanwhile, a mounting eye 14 is fixed to the first side surface of the bottom cover 13 of the cylinder section 10, for example, by welding. Then, a cylinder 11 with a bottom section 40 pressed into the inside is inserted into the outer cylinder 12, second to the bottom cover 13. The outer cylinder assembly is assembled in this way. 【0026】 Subsequently, the rod assembly is inserted into the cylinder 11 of the outer cylinder assembly from the nut 35 side. Then, the second end of the outer cylinder 12 is bent inward, a so-called roll crimping process, to fix the rod guide portion 15 and the oil seal 16 between the cylinder 11 and the crimped portion 12R (see Figure 1) of the outer cylinder 12. Subsequently, the dust cover 50 is attached to the disc-shaped portion 145 of the intermediate member 120 of the mounting eye 100. 【0027】 The manufacturing method of the shock absorber 1 is not limited to the method described above. For example, the mounting eye 100 may be joined to the rod 20 after the rod 20 has been assembled to the cylinder portion 10. In other words, before joining the mounting eye 100 to the rod 20, the oil seal 16, rod guide portion 15, rebound rubber 18, and rebound seat 17 are assembled to the rod 20 in order, and the rebound seat 17 is fixed to the rod 20. The piston portion 30 is then assembled to the rod 20 and fixed with a nut 35. After that, the outer cylinder assembly is inserted into the cylinder 11 from the nut 35 side, and the rod guide portion 15 and oil seal 16 are fixed to the cylinder 11 with the crimp portion 12R (see Figure 1). Next, the mounting eye 100 is joined to the rod 20. The dust cover 50 is then joined to the disc-shaped portion 145 of the intermediate member 120 of the mounting eye 100. 【0028】 As described above, the shock absorber 1 comprises a cylinder portion 10 in which oil, as an example of a working fluid, is sealed, and a piston portion 30 inserted into the cylinder portion 10. The shock absorber 1 also comprises a rod 20 whose lower end 21 (an example of one end) is connected to the piston portion 30 and whose upper end 22 (an example of the other end) is exposed to the outside of the cylinder portion 10. The shock absorber 1 also comprises a mounting eye 100 attached to the upper end 22 of the rod 20, and a dust cover 50 that covers the portion of the rod 20 exposed from the cylinder portion 10. The eye body 101 of the mounting eye 100 has a tip member 110 located on the second end side, and an intermediate member 120 provided between the tip member 110 and the rod 20 and joined to the tip member 110 and the rod 20. The intermediate member 120 has a cylindrical portion 130 (an example of a tubular portion) and a closing portion 140 that closes one (for example, the second side) opening of the cylindrical portion 130. Furthermore, the intermediate member 120 has a disc-shaped portion 145 (an example of a holding portion) provided on the other (for example, the first side) opening side of the cylindrical portion 130 for holding the dust cover 50. The cylindrical portion 130 is joined to the upper end portion 22 of the rod 20, and the portion of the closing portion 140 opposite to the cylindrical portion 130 is joined to the tip member 110. 【0029】 According to the buffer device 1, the eye body 101 of the mounting eye 100 is composed of two parts: a tip member 110 and an intermediate member 120 that is joined to the tip member 110 and the dust cover 50. Therefore, it is possible to reduce costs compared to when it is composed of three parts. In other words, when the eye body 101 is composed of two parts, material costs and parts management costs can be reduced compared to when it is composed of three parts, thus lowering costs. This two-part composition of the eye body 101 is achieved by providing a cylindrical portion 130 that is joined to the upper end 22 of the rod 20 and a disc-shaped portion 145 that holds the dust cover 50 on the intermediate member 120. Furthermore, by providing the disc-shaped portion 145 on the first opening side of the cylindrical portion 130, it is possible to provide the cylindrical portion 130 and the disc-shaped portion 145 on the intermediate member 120 without adversely affecting the joining with the tip member 110. 【0030】 Furthermore, if the eye body is composed of three parts and the three parts are joined simultaneously, the positioning of the three parts during joining can be difficult, potentially leading to a deterioration in joining accuracy. However, since the eye body 101 consists of only two parts, the joining accuracy is high. For example, the axial direction of the rod 20 and the centerline direction of the dust cover 50 tend to coincide. Also, the axial direction of the rod 20 and the centerline direction of the tip member 110 tend to be perpendicular to each other. Furthermore, if the eye body is composed of three parts and the three parts are to be joined by welding simultaneously, it is necessary to set all three parts in the welding machine. However, since the eye body 101 consists of two parts, it is sufficient to set only two parts in the welding machine, thus reducing the amount of work required for welding. 【0031】 Furthermore, the cylindrical portion 130 is joined to the upper end 22 (an example of the second end) of the rod 20 by applying pressure from the outside inward while the upper end 22 of the rod 20 is inserted inside. This allows the eye body 101 and the rod 20 to be joined without welding the eye body 101 and the rod 20 of the mounting eye 100. 【0032】 Furthermore, a groove 24 recessed from the outer surface 23 (an example of an outer surface) is formed at the upper end 22 of the rod 20. The cylindrical portion 130 has a joint portion 132 that is pressed into the groove 24 and joined by pressure, and a pressing portion 135 that is provided at a different position in the axial direction from the groove 24 on the rod 20 and is pressed toward the outer surface 23. This allows a part of the cylindrical portion 130 to be plastically deformed and pressed into the groove 24 with high accuracy. 【0033】 The cylindrical portion 130 is pressurized at multiple points in the circumferential direction and has multiple joint portions 132 and pressing portions 135. This makes it possible to increase the joint strength between the rod 20 and the mounting eye 100 compared to when the cylindrical portion 130 is pressurized at only one point. [Explanation of symbols] 【0034】 1... Shock absorber, 10... Cylinder section, 20... Rod, 21... Lower end (an example of one end), 22... Upper end (an example of the other end), 24... Groove, 30... Piston section, 50... Dust cover, 100... Mounting eye, 101... Eye body, 110... Tip member, 120... Intermediate member, 130... Cylindrical section, 132... Joint section, 135... Pressing section, 140... Blocking section, 145... Disc-shaped section

Claims

[Claim 1] The cylinder section, which contains the working fluid, The piston portion inserted into the cylinder portion, A rod having one end connected to the piston and the other end exposed to the outside of the cylinder, A mounting eye attached to the other end of the rod, A dust cover covering the portion of the rod exposed from the cylinder portion, Equipped with, The eye body of the mounting eye comprises a tip member positioned closest to the other end, and an intermediate member provided between the tip member and the rod and joined to the tip member and the rod. It has, The intermediate member has a cylindrical portion, a closing portion that closes one opening in the cylindrical portion, and a holding portion provided on the other opening side of the cylindrical portion for holding the dust cover, the cylindrical portion being joined to the other end of the rod, and the portion of the closing portion opposite to the cylindrical portion being joined to the tip member. Buffer device. [Claim 2] The cylindrical portion is joined to the other end of the rod by applying pressure from the outside inward while the other end of the rod is inserted inside the cylindrical portion. The shock absorber according to claim 1. [Claim 3] The other end of the rod has a groove formed in the outer surface, The cylindrical portion has a joint portion that is pressed into the groove and joined by pressure, and a pressing portion that is provided at a position in the rod that is different in the axial direction from the groove and is pressed toward the outer surface, in a continuous manner. The shock absorber according to claim 1. [Claim 4] The cylindrical portion is pressurized at multiple locations in the circumferential direction and has multiple joint portions and pressing portions. The shock absorber according to claim 3. [Claim 5] After the rod is assembled to the cylinder portion, the mounting eye is joined to the rod. The shock absorber according to claim 1.

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