Cylinder Device

Abstract

To provide a cylinder device capable of preventing knocking from occurring when a guide rod and a piston rod are displaced integrally. [Solution] The cylinder device (10) includes a body (12), a piston rod (20) inserted into a first insertion hole (14) of the body (12), a guide rod (50) inserted into a second insertion hole (16) of the body (12), and a bushing (60) housed in the second insertion hole (16). The bushing (60) has an insertion hole (62), an opening (64), and a chamfered portion (66). The guide rod (50) passes through the opening (64) and the chamfered portion (66) and is inserted into the insertion hole (62). The chamfered portion (66) has a plurality of tapered surfaces (68). The taper angles of two adjacent surfaces of the plurality of tapered surfaces (68) are different from each other.

Description

[Technical Field]

[0001] The present disclosure relates to a cylinder device. [Background technology]

[0002] The linear actuator disclosed in JP 2016-8669 A includes a fixed shaft and a mover with the fixed shaft passing through an insertion hole. Two bushings (bearings) are provided at both ends of the mover in the axial direction. The fixed shaft also passes through an insertion hole provided in each of the two bushings. This type of bushing is often made of sintered metal and contains lubricant.

[0003] Each of the two bushings has a chamfered portion formed on at least one of the axial ends of the insertion hole. According to JP 2016-8669 A, the chamfered portion suppresses the generation of abnormal noise when the linear actuator is driven and also suppresses variations in the vibration frequency of the mover. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-8669 Summary of the Invention [Problem to be solved by the invention]

[0005] In a cylinder device, knocking may occur when the guide rod and the piston rod are displaced together, and there is a demand for preventing this knocking.

[0006] The present disclosure aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] An aspect of the present disclosure is a cylinder device comprising: a body; a first insertion hole and a second insertion hole extending along the axial direction of the body and aligned parallel to each other; a piston rod displaceably inserted into the first insertion hole; a connecting member connected to one axial end of the piston rod; a guide rod displaceably inserted into the second insertion hole and having one axial end connected to the connecting member so as to displace integrally with the piston rod; and a bushing housed in the second insertion hole, wherein the bushing has a main body member, an insertion hole penetrating the main body member along the axial direction, an opening located on an end face of the main body member and having a diameter larger than that of the insertion hole, and a chamfered portion located between the opening and the insertion hole, wherein the guide rod passes through the opening and the chamfered portion and is inserted into the insertion hole, and the chamfered portion has a plurality of tapered surfaces, and two adjacent tapered surfaces among the plurality of tapered surfaces have different taper angles. [Effects of the Invention]

[0008] According to the present disclosure, the support area of ​​the guide rod in the bush is large, so that knocking can be avoided when the guide rod and the piston rod are displaced together. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic plan cross-sectional view of a cylinder device according to an embodiment of the present disclosure, cut along the axial direction. [Figure 2] FIG. 2 is a cross-sectional plan view of a main part of the cylinder device. [Figure 3] FIG. 3 is a partially enlarged plan view of the bushing and the guide rod. [Figure 4] FIG. 4 is a schematic cross-sectional plan view showing a state in which the piston rod and the guide rod are displaced from the state shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, to simplify the explanation and make it easier to understand, one axial end of each component of the cylinder device 10 shown in Fig. 1 may be referred to as a first end, and the other axial end of each component may be referred to as a second end. The first end is the end facing the X1 direction in Fig. 1, and the second end is the end facing the X2 direction in Fig. 1.

[0011] FIG. 1 is a schematic plan cross-sectional view of a cylinder device 10 according to this embodiment, cut along the axial direction. This cylinder device 10 includes a body 12. The body 12 is formed with a first insertion hole 14 and a plurality of (two in the illustrated example) second insertion holes 16. The first insertion hole 14 is located between the two second insertion holes 16. The first insertion hole 14 and the two second insertion holes 16 extend along the axial direction (longitudinal direction) of the body 12 and are aligned parallel to one another. Note that the number of second insertion holes 16 may be one.

[0012] The cylinder device 10 further includes a piston rod 20 and two guide rods 50. The piston rod 20 is displaceably inserted into the first insertion hole 14. The two guide rods 50 are displaceably inserted into the two second insertion holes 16, respectively. A first end of the piston rod 20 is exposed from a first end of the first insertion hole 14. A first end of each guide rod 50 is exposed from a first end of each second insertion hole 16. The first end of the piston rod 20 and the first ends of the two guide rods 50 are connected to a connecting member 40 via a bolt 42. In other words, the piston rod 20 and the two guide rods 50 are integrated by the connecting member 40.

[0013] The first insertion hole 14 extends linearly along the axial direction of the body 12 and penetrates the body 12. A cap member 38 is provided at the second end of the first insertion hole 14. The cap member 38 closes the second end of the first insertion hole 14. The diameter of the first insertion hole 14 is, for example, 6 mm to 10 mm, but may be greater than 10 mm.

[0014] The first insertion hole 14 is divided into a first inner chamber 143 and a second inner chamber 144. Specifically, the first inner chamber 143 is formed between the rod cover 30 and the piston 22, and the second inner chamber 144 is formed between the piston 22 and the cap member 38. The first inner chamber 143 communicates with a first supply / discharge port (not shown), and the second inner chamber 144 communicates with a second supply / discharge port (not shown). A first compressed air supply / discharge mechanism (not shown) is connected to the first supply / discharge port, and a second compressed air supply / discharge mechanism (not shown) is connected to the second supply / discharge port.

[0015] The first end of the first insertion hole 14 is connected to the accommodation hole 15. The diameter of the accommodation hole 15 is larger than the diameter of the first insertion hole 14.

[0016] A rod cover 30 is accommodated in the accommodating hole 15. First teeth 31 are formed on the outer peripheral surface of the rod cover 30, and second teeth 145 are formed on the inner peripheral surface of the accommodating hole 15. The first teeth 31 and the second teeth 145 mesh with each other. Furthermore, a first seal ring 34 is attached to the outer peripheral surface of the rod cover 30 at a position closer to the first end. The first seal ring 34 seals between the outer peripheral surface of the rod cover 30 and the inner peripheral surface of the accommodating hole 15. Meanwhile, a second seal ring 36 is attached to the inner peripheral surface of the rod cover 30. The second seal ring 36 seals between the inner peripheral surface of the rod cover 30 and the side peripheral surface of the piston rod 20.

[0017] Although not shown, a scraper may be held on the inner circumferential surface of the rod cover 30. The scraper has a lip portion that protrudes annularly toward the inner periphery. This lip portion comes into contact with the side circumferential surface of the piston rod 20.

[0018] A piston 22 is attached to the second end of the piston rod 20. For example, a male threaded portion is provided at the second end of the piston rod 20, and a female threaded portion is provided at the first end of the piston 22. The male threaded portion is screwed into the female threaded portion.

[0019] The piston 22 has an annular groove 223 on its outer circumferential surface. A seal ring 25 is fitted in the annular groove 223. A first damper 24 is provided at a first end of the piston 22, and a second damper 28 is provided at a second end of the piston 22. The second damper 28 is held in a recess 225 in the second end of the piston 22.

[0020] The second insertion hole 16 has a large diameter hole portion 161 at a first end and a small diameter hole portion 163 at a second end. The second insertion hole 16 further has a medium diameter hole portion 162 located between the large diameter hole portion 161 and the small diameter hole portion 163.

[0021] The large diameter hole portion 161 accommodates the lubricant holding member 52. Therefore, the lubricant holding member 52 is disposed between the opening 164 of the second insertion hole 16 and the bushing 60 in the axial direction (extension direction) of the second insertion hole 16. The material of the lubricant holding member 52 is, for example, sponge or self-lubricating fiber, and it holds a lubricant (for example, lubricating oil) well. In the illustrated example, the lubricant holding member 52 is held by an annular holder 54.

[0022] Two bushings 60 are housed in the medium diameter hole portion 162. Hereinafter, the one of the two bushings 60 located on the first end side will be referred to as the first bushing 60a, and the one of the two bushings 60 located on the second end side will be referred to as the second bushing 60b. In the axial direction of the second insertion hole 16, the first bushing 60a and the second bushing 60b are spaced apart from each other by a predetermined distance.

[0023] 2, the first bushing 60a has a main body member 61 and an insertion hole 62 that passes through the main body member 61 in the axial direction. The first bushing 60a further has an opening 64 that is larger in diameter than the insertion hole 62, and a chamfered portion 66 that is located between the opening 64 and the insertion hole 62. The opening 64 has a first opening 64a located in the end face of the main body member 61 on the first end side, and a second opening 64b located in the end face of the main body member 61 on the second end side.

[0024] The chamfered portion 66 has a first chamfered portion 66a located between the first opening 64a and the insertion hole 62, and a second chamfered portion 66b located between the insertion hole 62 and the second opening 64b. The guide rod 50 is inserted into the insertion hole 62 by passing through the first opening 64a (or the second opening 64b) and the first chamfered portion 66a (or the second chamfered portion 66b).

[0025] The first chamfered portion 66a has a plurality of tapered surfaces 68. In the illustrated example, an embodiment in which there are three tapered surfaces 68 is shown. That is, in this embodiment, the first chamfered portion 66a has, in order from the insertion hole 62 toward the first opening 64a, a first tapered surface 68a, a second tapered surface 68b, and a third tapered surface 68c. The first tapered surface 68a is an innermost tapered surface 681 that is closest to the insertion hole 62. As shown in FIG. 3, the end of the first tapered surface 68a that faces the insertion hole 62 (the end of the taper) is a first hole-side end portion 68aE.

[0026] As shown in FIG. 3, the first tapered surface 68a, the second tapered surface 68b, and the third tapered surface 68c intersect with the axis A of the first bushing 60a at a first taper angle α, a second taper angle β, and a third taper angle γ, respectively. The first taper angle α is different from the second taper angle β, and the second taper angle β is different from the third taper angle γ. In this manner, the taper angles of two adjacent surfaces among the multiple tapered surfaces 68 are different from each other. Note that FIG. 3 shows a cross section of the first bushing 60a cut along the axial direction (axis A) as viewed from the radial direction. The first taper angle α and the third taper angle γ may be equal to each other.

[0027] 3, an imaginary C-chamfered portion 70 is formed by drawing an imaginary oblique line SL inclined at 45 degrees from the periphery 64aE of the first opening 64a with respect to the axial direction (axis A) of the insertion hole 62. The intersection of the imaginary oblique line SL with the insertion hole 62 is the end (second-hole-side end 70E) of the imaginary C-chamfered portion 70 that faces the insertion hole 62. The first-hole-side end 68aE of the first tapered surface 68a, which is the innermost tapered surface 681, is preferably closer to the first opening 64a than the second-hole-side end 70E.

[0028] Furthermore, the first taper angle α of the first tapered surface 68a is preferably smaller than 45°, which is the inclination angle of the imaginary C-chamfered portion 70. In this case, it is easy to position the first hole-side end portion 68aE closer to the first opening 64a than the second hole-side end portion 70E.

[0029] FIG. 3 shows the imaginary R-chamfered portion 72. Here, the imaginary R-chamfered portion 72 is an arc of a circle with a central angle of 90° and the imaginary C-chamfered portion 70 as a chord. Both ends of the imaginary R-chamfered portion 72 are connected to the periphery 64aE of the first opening 64a and the second hole-side end portion 70E, respectively. As shown in FIG. 3, the entire outline of the chamfered portion 66 may be located outward from the outline of the imaginary R-chamfered portion 72. However, the entire outline of the chamfered portion 66 may also be located inward from the outline of the imaginary R-chamfered portion 72. Alternatively, a portion of the outline of the chamfered portion 66 may be located outward from the outline of the imaginary R-chamfered portion 72, and another portion of the outline of the chamfered portion 66 may be located inward from the outline of the imaginary R-chamfered portion 72.

[0030] The second chamfered portion 66b is formed in the same manner as the first chamfered portion 66a, and therefore a detailed description of the second chamfered portion 66b will be omitted.

[0031] One example of the material for the first bushing 60a configured as described above is sintered metal. The first bushing 60a made of sintered metal is obtained by sintering metal powder. This first bushing 60a is porous and has pores with a three-dimensional network structure inside. These pores hold a lubricant such as lubricating oil. Therefore, it is not necessary to constantly supply a lubricant to the first bushing 60a.

[0032] The first bushing 60a may be made of metal, in which case it is preferable to provide a lubricating coating on the inner surface of the first bushing 60a.

[0033] The second bushing 60b is configured in the same manner as the first bushing 60a, and therefore the same components are given the same reference numerals and detailed description thereof will be omitted.

[0034] Next, the operation of the cylinder device 10 will be described.

[0035] When the piston rod 20 is moved in the X1 direction from the state shown in FIG. 1 , compressed air is supplied from the second supply / exhaust mechanism to the second inner chamber 144 via the second supply / exhaust port. Meanwhile, the compressed air in the first inner chamber 143 is discharged by the first supply / exhaust mechanism via the first supply / exhaust port. Therefore, the internal pressure of the second inner chamber 144 becomes higher than the internal pressure of the first inner chamber 143. Therefore, the piston 22 is pushed by the compressed air in the second inner chamber 144. As a result, the piston 22, the piston rod 20, the two guide rods 50, and the connecting member 40 move integrally in the X1 direction. In other words, the piston rod 20 is displaced in the X1 direction while being guided by the two guide rods 50. As a result, the state shown in FIG. 4 is formed. The second ends of each second insertion hole 16 are open ends, and these open ends function as an entrance / exit for the atmosphere when the guide rods 50 are displaced.

[0036] In contrast, when the piston rod 20 is moved in the X2 direction from the state shown in FIG. 4, compressed air is supplied from the first supply / discharge mechanism to the first inner chamber 143 via the first supply / discharge port. Meanwhile, the compressed air in the second inner chamber 144 is discharged by the second supply / discharge mechanism via the second supply / discharge port. As a result, the internal pressure of the first inner chamber 143 becomes greater than the internal pressure of the second inner chamber 144. Therefore, the piston 22 is pushed by the compressed air in the first inner chamber 143. As a result, the piston 22, the piston rod 20, the two guide rods 50, and the connecting member 40 move integrally in the X2 direction. This returns the cylinder device 10 to the state shown in FIG. 1.

[0037] If a scraper is provided on the rod cover 30, when the piston rod 20 is displaced as described above, the side circumferential surface of the piston rod 20 comes into sliding contact with the lip portion of the scraper. Therefore, if foreign matter such as dust adheres to the side circumferential surface of the piston rod 20 at the portion exposed from the first insertion hole 14, the foreign matter is scraped off by the lip portion of the scraper. This prevents the foreign matter from entering the first insertion hole 14.

[0038] Furthermore, if foreign matter such as dust adheres to the side circumferential surface of the portion of the guide rod 50 exposed from the second insertion hole 16, the foreign matter is scraped off by the lubricant retaining member 52. This prevents the foreign matter from entering the second insertion hole 16.

[0039] The cylinder device 10 according to this embodiment has the following advantages when operating as described above. In the following description, the first opening 64a and the second opening 64b may be collectively referred to as the opening 64, and the first bushing 60a and the second bushing 60b may be collectively referred to as the bushing 60. Similarly, the first chamfered portion 66a and the second chamfered portion 66b may be collectively referred to as the chamfered portion 66.

[0040] 3, in this embodiment, the chamfered portion 66 is formed by a plurality of tapered surfaces 68. In this case, it is easy to position the first hole-side end portion 68aE of the chamfered portion 66, which is the end facing the insertion hole 62, closer to the opening 64 (the end face in the axial direction of the main body member 61) than the second hole-side end portion 70E of the imaginary C-chamfered portion 70.

[0041] In other words, the depth position of the first hole-side end 68aE of the chamfered portion 66 is shallower than the depth position of the second hole-side end 70E of the imaginary C-chamfered portion 70. Therefore, in the bushing 60 formed with the chamfered portion 66, the support area for the guide rod 50 is larger than in the bushing formed with the imaginary C-chamfered portion 70. Therefore, the linear movement of the guide rod 50 is stabilized.

[0042] Furthermore, the contact angle (first taper angle α) of the chamfered portion 66 with respect to the guide rod 50 is smaller than the contact angle (45°) of the imaginary C-chamfered portion 70 with respect to the guide rod 50. Therefore, vibration is less likely to occur when the guide rod 50 slides against the inner circumferential surface of the insertion hole 62.

[0043] For the reasons described above, even when the piston rod 20 is displaced with low power because the first insertion hole 14 shown in Figures 1 and 4 has a small diameter (for example, 6 mm to 10 mm), knocking can be avoided. In other words, the piston rod 20 and the guide rod 50 are displaced smoothly. This reduces wear on the piston rod 20 and the guide rod 50, thereby extending the life of the cylinder device 10.

[0044] Furthermore, since the support area of ​​the bushing 60 relative to the guide rod 50 is large, the axial length of the bushing 60 can be made smaller than that of a bushing provided with a C-chamfered portion conforming to the imaginary C-chamfered portion 70 .

[0045] When the diameter of the first insertion hole 14 is set to 6 mm to 10 mm, the piston rod 20, the guide rod 50, etc. can be made into a small-sized cylinder device 10 with small diameters.

[0046] When the bushing 60 is made of sintered metal, the bushing 60 can retain a lubricant such as lubricating oil within the pores. Therefore, there is no need to supply a lubricant to the second insertion hole 16 when the cylinder device 10 operates.

[0047] When the cylinder device 10 is provided with the lubricant holding member 52, the lubricant holding member 52 holds a lubricant such as lubricating oil, allowing smooth displacement of the guide rod 50. Furthermore, when the lubricant holding member 52 is held by the holder 54, the lubricant holding member 52 is prevented from shifting position.

[0048] Furthermore, the lubricant retaining member 52 disposed between the opening 164 of the second insertion hole 16 and the bushing 60 scrapes off foreign matter adhering to the side circumferential surface of the portion of the guide rod 50 exposed from the second insertion hole 16. This prevents foreign matter from entering the second insertion hole 16.

[0049] The following additional notes are further disclosed regarding the above embodiment.

[0050] (Appendix 1) The cylinder device (10) of the present disclosure includes a body (12), a first insertion hole (14) and a second insertion hole (16) extending along the axial direction of the body and aligned parallel to each other, a piston rod (20) displaceably inserted into the first insertion hole, a connecting member (40) connected to one end of the piston rod in the axial direction, a guide rod (50) displaceably inserted into the second insertion hole and having one end in the axial direction connected to the connecting member so as to displace integrally with the piston rod, and a guide rod (50) accommodated in the second insertion hole. and a bushing (60) fitted to the bushing, the bushing having a main body member (61), an insertion hole (62) penetrating the main body member along the axial direction, an opening (64) located on the axial end face of the main body member and having a diameter larger than that of the insertion hole, and a chamfered portion (66) located between the opening and the insertion hole, the guide rod passes through the opening and the chamfered portion and is inserted into the insertion hole, the chamfered portion having a plurality of tapered surfaces (68), and the taper angles of two adjacent surfaces among the plurality of tapered surfaces are different from each other.

[0051] As described above, in the present disclosure, the chamfered portion is formed with multiple tapered surfaces. In this case, the end of the chamfered portion facing the insertion hole (the first-hole side end) is closer to the end face or opening in the axial direction of the main body member than the end of the C-chamfered portion (the second-hole side end). In other words, the depth position of the first-hole side end of the chamfered portion is shallower than the depth position of the second-hole side end of the C-chamfered portion.

[0052] Therefore, the chamfered portion has a larger support area for the guide rod than the C-chamfered portion. Based on this, the present disclosure stabilizes the linear movement of the guide rod. Furthermore, the chamfered portion has a smaller contact angle with the guide rod than the C-chamfered portion. Therefore, vibration is less likely to occur when the guide rod slides against the chamfered portion.

[0053] For these reasons, knocking can be avoided even when the piston rod is displaced at low power. In other words, the piston rod and the guide rod are displaced smoothly. This reduces wear on the piston rod and the guide rod, thereby extending the life of the cylinder.

[0054] Furthermore, since the support area of ​​the chamfered portion for the guide rod is large, the axial length of the bushing can be made shorter than when a C-chamfered portion is provided.

[0055] (Appendix 2) In the cylinder device described in Supplementary Note 1, the inclination angle of an innermost tapered surface (681), which is the tapered surface among the plurality of tapered surfaces that is closest to the insertion hole, may be less than 45°.

[0056] In this case, it is possible to form a chamfered portion that is gentler than a C-chamfered portion, and it is also easy to make the depth position of the first hole side end shallower than the depth position of the second hole side end.

[0057] (Appendix 3) In the cylinder device described in Appendix 1 or 2, when a virtual C-chamfered portion (70) inclined at 45 degrees from the peripheral edge (64aE) of the opening to the axial direction of the insertion hole is formed, the first hole side end (68aE), which is the end facing the insertion hole, of the innermost tapered surface (681), which is the tapered surface among the multiple tapered surfaces that is closest to the insertion hole, may be closer to the opening than the second hole side end (70E), which is the end facing the insertion hole, of the virtual C-chamfered portion.

[0058] In this case, it is easy to increase the support area of ​​the bush for the guide rod.

[0059] (Appendix 4) In the cylinder device according to any one of Supplementary Notes 1 to 3, the first insertion hole may have a diameter of 6 mm to 10 mm.

[0060] When the first insertion hole has a small diameter as described above, the piston rod and piston also have small diameters, so that even when the output of the cylinder device is low, the piston rod can be displaced sufficiently smoothly.

[0061] (Appendix 5) In the cylinder device according to any one of Supplementary Notes 1 to 4, the bushing may be made of a sintered metal.

[0062] Since sintered metal is a porous body, it is possible to retain a lubricant such as lubricating oil in the pores.

[0063] (Appendix 6) The cylinder device described in any one of Supplementary Notes 1 to 5 may include a lubricant holding member (52) that is housed in the second insertion hole while holding a lubricant and with which the side peripheral surface of the guide rod slides.

[0064] This configuration allows the guide rod to be displaced more smoothly.

[0065] (Appendix 7) In the cylinder device described in Supplementary Note 6, the lubricant holding member may be disposed between an opening of the second insertion hole and the bush in the extending direction of the second insertion hole.

[0066] The lubricant holding member prevents foreign matter from entering the second insertion hole.

[0067] (Appendix 8) The cylinder device according to Supplementary Note 7 may further include a holder (54) that holds the lubricant holding member.

[0068] With this configuration, the lubricant holding member is less likely to become displaced.

[0069] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0070] 10...Cylinder device 12...Body 14...First insertion hole 16...Second insertion hole 20...Piston rod 22...Piston 40...Connecting member 50...Guide rod 52...Lubricant holding member 54...Holder 60, 60a, 60b... bushing 61... main body member 62...through hole 64, 64a, 64b...openings 64aE...periphery of opening 66, 66a, 66b...chamfered portion 68, 68a to 68c... Tapered surfaces 68aE... First hole side end 70... Virtual C-chamfered portion 70E... End portion on the second hole side 72...Virtual R chamfered portion 681...Innermost tapered surface

Claims

1. Body and a first insertion hole and a second insertion hole extending along the axial direction of the body and aligned parallel to each other; a piston rod displaceably inserted into the first insertion hole; a connecting member connected to one end of the piston rod in the axial direction; a guide rod that is displaceably inserted into the second insertion hole and has one axial end connected to the connecting member so as to be displaced integrally with the piston rod; a bushing accommodated in the second insertion hole; Equipped with the bushing has a main body member, an insertion hole penetrating the main body member along the axial direction, an opening located on an end surface of the main body member in the axial direction and having a diameter larger than that of the insertion hole, and a chamfered portion located between the opening and the insertion hole, the guide rod passing through the opening and the chamfered portion and inserted into the insertion hole, The chamfered portion has a plurality of tapered surfaces, and two adjacent surfaces of the plurality of tapered surfaces have different taper angles.

2. 2. The cylinder device according to claim 1, wherein an inclination angle of an innermost tapered surface, which is the tapered surface closest to the insertion hole among the plurality of tapered surfaces, is less than 45 degrees.

3. 2. The cylinder device according to claim 1, wherein, when a virtual C-chamfered portion inclined at 45° from the periphery of the opening with respect to the axial direction of the insertion hole is formed, a first hole side end portion, which is an end portion facing the insertion hole, of an innermost tapered surface that is the tapered surface closest to the insertion hole among the plurality of tapered surfaces, is closer to the opening than a second hole side end portion, which is an end portion facing the insertion hole, of the virtual C-chamfered portion.

4. 2. The cylinder device according to claim 1, wherein the diameter of the first insertion hole is 6 mm to 10 mm.

5. 2. The cylinder device according to claim 1, wherein the bushing is made of a sintered metal.

6. 2. The cylinder device according to claim 1, further comprising a lubricant holding member that is housed in the second insertion hole while holding a lubricant, and with which a side peripheral surface of the guide rod makes sliding contact.

7. 7. The cylinder device according to claim 6, wherein the lubricant holding member is disposed between the opening of the second insertion hole and the bush in the extending direction of the second insertion hole.

8. The cylinder device according to claim 7, further comprising a holder for holding the lubricant holding member.

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