JP2009092152A - Fluid pressure cylinder with guiding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid pressure cylinder with a guide device which can improve the linear movement performance of a piston rod. <P>SOLUTION: The fluid pressure cylinder 100 with the guide device is provided with the piston rod 10 and a cylindrical guide 70. The piston rod 10 is attached to a piston 20 which is installed in a tube 30 so that it can freely reciprocate in the axial direction, and has an outer peripheral surface 10a axially projected from the tube 30 to the outside. The cylindrical guide 70 is attached to the tube 30 so that it can guide the movement of the piston rod 10 along the axial direction which is projected from the tube 30 to the outside. The cylindrical guide 70 includes a guide body 70a and an outer ring 81. The guide body 70a has a through hole 70b in which the piston rod 10 can be inserted, and the outer ring 81 provided to the through hole 70b can roll axially on the outer peripheral surface 10a of the piston rod 10. The outer ring 81 is provided in the through hole 70b so that it is brought into close contact with the outer peripheral surface 10a of the piston rod 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates generally to a fluid pressure cylinder, and more particularly to a fluid pressure cylinder with a guide device to which a device for guiding the movement of a piston rod that protrudes axially outward from the cylinder body due to fluid pressure is attached. It is.

  2. Description of the Related Art Conventionally, there is a fluid pressure cylinder as a reciprocating actuator that is operated by air pressure or hydraulic pressure, and it is widely used as a linear motion drive source in various industrial machines such as automatic processing machines constituting a production line. For example, as disclosed in Japanese Patent Application Laid-Open No. 2004-232663 (Patent Document 1), a fluid pressure cylinder includes a cylinder tube that houses a piston that reciprocates linearly by fluid pressure, and a cylinder that is attached to the piston. A piston rod protruding outward from the end surface of the tube and a rod cover attached to the end surface of the cylinder tube are provided.

In the fluid pressure cylinder configured as described above, the piston is held in the cylinder chamber by the wear ring, but there is a clearance of, for example, about 0.1 mm between the piston and the piston rod. Further, on the side where the piston rod comes in and out of the cylinder body, a metal bush is disposed between the rod cover and the piston rod. For example, a clearance of about 0.1 mm exists between the metal bush and the piston rod.
JP 2004-232663 A

  As described above, in the conventional hydraulic cylinder, the piston rod is incorporated into the cylinder body so that a clearance of, for example, about 0.1 mm exists. For this reason, when the piston rod is in the forward limit position protruding outward from the cylinder body, if a load is applied to the piston rod from a direction orthogonal to the axial direction, the piston rod may become loose due to the presence of the clearance. I'm rattling. As a result, there is a problem in that the movement of the piston rod along the axial direction is inferior in linearity.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fluid pressure cylinder with a guide device that can improve the straightness of a piston rod.

  A fluid pressure cylinder with a guide device according to the present invention includes a cylinder body in which a cylinder chamber is formed, a piston mounted so as to be capable of reciprocating in an axial direction in the cylinder chamber, and attached to the piston. A piston rod having an outer peripheral surface projecting in the axial direction, and one of the cylinder body on the side where the piston rod enters and exits to guide the movement of the piston rod projecting outward from the cylinder body along the axial direction. And a guide device attached to the end. The guide device includes a guide main body having a through hole into which the piston rod can be inserted, and a rolling element provided in the through hole of the guide main body and capable of rolling on the outer peripheral surface of the piston rod in the axial direction. The rolling element is provided in the through hole of the guide body so that the rolling element comes into close contact with the outer peripheral surface of the piston rod.

  As described above, the rolling element is provided in the through hole of the guide body so as to be in close contact with the outer peripheral surface of the piston rod without any gap, so that the piston rod protrudes from the cylinder body to the outside in the axial direction to the forward limit. In this case, even if a load is applied to the piston rod from the direction orthogonal to the axial direction, the piston rod does not wobble and the piston rod can be moved in the axial direction. Thereby, the straight advanceability of the piston rod can be improved.

  Also, when the piston rod protrudes from the cylinder body to the outside in the axial direction to the forward limit, even if a load is applied to the piston rod from the direction orthogonal to the axial direction, the piston and the inner wall surface of the cylinder chamber are in direct contact. The O-ring and packing arranged so as to be interposed between the piston and the inner wall surface of the cylinder chamber are less likely to cause uneven wear, and internal oil leakage is less likely to occur.

  When the fluid pressure cylinder is a hydraulic cylinder, oil in the cylinder chamber adheres to the outer peripheral surface of the piston rod every time the piston rod protrudes and moves outside the cylinder chamber. For this reason, the lubricating oil is automatically supplied to the rolling elements that are in close contact with the outer peripheral surface of the piston rod. Thereby, rolling to the axial direction of a rolling element can be made smooth.

  In the fluid pressure cylinder with a guide device according to the present invention, a plurality of pocket holes arranged in the circumferential direction in a plane orthogonal to the axial direction are formed on the inner surface of the through hole of the guide body in the axial direction. The rolling element is formed in each of the plurality of pocket holes of the guide body, and can roll on the outer peripheral surface of the piston rod in the axial direction. The guide device can rotate the rolling element. It is preferable that a support shaft member to be supported is further included.

  By configuring the guide device in this way, the movement along the axial direction of the piston rod is guided so that a differential slip is not substantially generated on the contact surface between the rolling element and the outer peripheral surface of the piston rod. can do.

  Further, in the fluid pressure cylinder with a guide device of the present invention, the piston rod has an outer peripheral surface whose cross section orthogonal to the axial direction is a substantially circular cross section, and the rolling element has a concave shape capable of contacting the outer peripheral surface of the piston rod. It is preferable to have a curved outer peripheral surface.

  By configuring the guide device in this way, the contact area between the outer peripheral surface of the piston rod and the outer peripheral surface of the rolling element whose cross section orthogonal to the axial direction is a substantially circular cross section can be increased. The pressure can be reduced. Thereby, smooth rotation of a rolling element is securable.

  Alternatively, in the fluid pressure cylinder with a guide device of the present invention, the piston rod has an outer peripheral surface including a plurality of planes extending in the axial direction, and a cylindrical outer periphery in which the rolling element can contact the plane of the piston rod. It may be configured to have a surface.

  By configuring the guide device in this manner, each of a plurality of axially extending planes constituting a part of the outer peripheral surface of the piston rod can be brought into contact with the cylindrical outer peripheral surface of the rolling element. It is possible to prevent the piston rod protruding outward from the main body from rotating around the axis.

  In the fluid pressure cylinder with a guide device of the present invention, the rolling element may be a rolling element such as a roller inserted in the retainer.

  In the fluid pressure cylinder with a guide device of the present invention, the rolling element may be a rolling element such as a ball or a roller that circulates inside the guide body.

  Even if the rolling element is configured with any of the above, the straightness of the piston rod can be improved.

  Furthermore, in the fluid pressure cylinder with a guide device of the present invention, a through hole into which a through bolt can be inserted is formed in the guide body so as to extend in the axial direction, and the through bolt is fastened and fixed to one end of the cylinder body. Thus, the guide device is preferably attached to the cylinder body.

  By doing in this way, a guide main body can be easily attached so that it may integrate with a cylinder main body, and a guide main body can be easily removed from a cylinder main body.

  In the fluid pressure cylinder with a guide device of the present invention, the piston rod includes a first piston rod portion disposed in the cylinder chamber and a second piston rod portion disposed outside the cylinder chamber, and the first piston rod The part and the second piston rod part are preferably detachably coupled.

  By doing in this way, the guide post in the linear motion mechanism of an automatic machine can be comprised by a 2nd piston rod part. Thereby, the guide post of the linear motion mechanism and the first piston rod portion arranged in the cylinder chamber of the fluid pressure cylinder can be separated from each other. Further, the first and second piston rod portions can be easily integrated and separated easily by being coupled with screws or the like.

  As described above, according to the present invention, even when a load is applied to the piston rod from the direction orthogonal to the axial direction when the piston rod protrudes from the cylinder body to the outside in the axial direction to the forward limit, Since the piston rod can be moved in the axial direction without rattling, there is no need for an additional guide device provided separately from the hydraulic cylinder, and the straightness of the piston rod is improved. Can do. For this reason, for example, when the fluid pressure cylinder with a guide device of the present invention is employed in a linear motion mechanism of an automatic machine that performs press-fitting and caulking work using movement of the piston rod itself of the fluid pressure cylinder, a compact linear motion guide device Can be configured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a partial sectional side view partially showing a hydraulic cylinder with a guide device as one embodiment of the present invention in a longitudinal section, and FIG. 2 is a transverse view seen from the direction along line II-II in FIG. FIG. 3 is a partial enlarged cross-sectional view showing a portion indicated by an arrow III in FIG. 2 in an enlarged manner.

  As shown in FIG. 1, a fluid pressure cylinder 100 with a guide device includes a tube 30 as a cylinder body in which a cylinder chamber is formed, and a piston 20 that is reciprocally mounted in the tube 30 in an axial direction. The piston rod 10 is attached to the piston 20 and has an outer peripheral surface protruding outward from the tube 30 and the piston rod 10 enters and exits to guide the movement along the axial direction of the piston rod 10 protruding outward from the tube 30. And a cylindrical guide 70 as a guide device attached to one end of the tube 30 on the side.

  A female screw portion 31 is formed on the inner peripheral wall surface at the other end portion of the tube 30. The head cover 50 is disposed so as to close the opening at the other end of the tube 30, and a male screw portion 51 that is screwed into the female screw portion 31 is formed. A port hole 53 is formed in the central portion of the head cover 50, and a female screw portion 52 is formed so that an instrument for supplying or discharging fluid can be attached. An O-ring 54 is fitted between the inner peripheral surface of the tube 30 and the outer peripheral surface of the head cover 50.

  A male screw portion 11 is formed at the other end of the piston rod 10. A female screw portion 23 for inserting and fixing the piston rod 10 is formed in the central portion of the piston 20. Between the outer peripheral surface of the other end of the piston rod 10 and the inner peripheral surface of the piston 20, an O-ring 12 is disposed. A wear ring 21 is fitted between the outer peripheral surface of the piston 20 and the inner peripheral surface of the tube 30, and U packings 22 are fitted on both sides of the wear ring 21.

  A rod cover 40 is inserted into one end of the tube 30, and an O-ring 41 is inserted between the inner peripheral surface of the tube 30 and the outer peripheral surface of the rod cover 40 at the insertion position. Yes. A port hole 43 is formed in the outer peripheral surface of the rod cover 40, and a device for supplying or discharging fluid is attached thereto. A metal bush 60 is interposed between the inner peripheral surface of the rod cover 40 and the outer peripheral surface of the piston rod 10. A U-packing 62 is fitted between the other end side surface of the metal bush 60 and the inner peripheral central side surface of the rod cover 40, and the inner peripheral surface of one end portion of the metal bush 60 and the piston rod 10 are inserted. A dust seal 61 is fitted between the outer peripheral surface.

  In the fluid pressure cylinder configured as described above, the piston 20 is held in the tube 30 by the wear ring 21, but as an example, between the inner peripheral surface of the piston 20 and the outer peripheral surface of the piston rod 10. A clearance of about 0.1 mm exists. Further, on the side where the piston rod 10 enters and exits the tube 30, the metal bush 60 is disposed between the rod cover 40 and the piston rod 10, but between the metal bush 60 and the piston rod 10. As an example, there is a clearance of about 0.1 mm. Thus, in the fluid pressure cylinder, the piston rod 10 is incorporated in the tube 30 so that a clearance of about 0.1 mm exists as an example.

  For this reason, when the piston rod 10 is in the forward limit position protruding outward from the tube 30 (the reverse limit position is shown in FIG. 1), the piston rod 10 is orthogonal to the axial direction as indicated by the arrow P. When a load is applied from the direction in which the piston rod 10 is moved, the piston rod 10 rattles due to the presence of the clearance. As a result, there is a problem that the movement of the piston rod 10 along the axial direction is inferior in linearity.

  Therefore, in one embodiment of the present invention, in order to improve the straightness of the piston rod, the cylindrical guide 70 as a guide device moves along the axial direction of the piston rod 10 protruding outward from the tube 30. Is attached to one end of the tube 30 on the side where the piston rod 10 enters and exits. A male screw portion 13 is formed at one end portion of the piston rod 10 so that a target member for linear movement using a fluid pressure cylinder is attached.

  As shown in FIGS. 1 to 3, the cylindrical guide 70 is provided in a guide main body 70 a having a through hole 70 b into which the piston rod 10 can be inserted, and a through hole 70 b in the guide main body 70 a, and the outer peripheral surface of the piston rod 10. An outer ring 81 of a needle bearing 80 is provided as a cylindrical rolling element capable of rolling on 10a. The outer ring 81 of the needle bearing 80 is provided in the through hole 70b of the guide body 70a so as to be in close contact with the outer peripheral surface 10a of the piston rod 10. For example, since the needle bearing 80 and the piston rod 10 are incorporated in a pressurized state, there is no gap between the outer peripheral surface 10 a of the piston rod 10 and the outer ring 81 of the needle bearing 80.

  Specifically, a plurality of pocket holes 73 are formed in a plurality of rows in the axial direction in the circumferential direction in a plane orthogonal to the axial direction on the inner side surface of the through hole 70b of the guide main body 70a, and the outer ring 81 of the needle bearing 80 is formed. It is provided in each of the plurality of pocket holes 73 of the guide body 70a. The outer ring 81 can roll in the axial direction on the outer peripheral surface 10 a of the piston rod 10, and is rotatably supported by a support shaft member 83.

  In the example shown in FIGS. 1 to 3, six pocket holes 73 are formed at intervals of 60 degrees in the circumferential direction. However, for example, three pocket holes may be provided at intervals of 120 degrees. Is appropriately set according to the diameter of the piston rod 10, the load applied to the cylindrical guide 70, and the like. In the example shown in FIGS. 1 to 3, six pocket holes 73 are arranged in the circumferential direction and the six pocket holes 73 are formed in two rows in the axial direction. It is set appropriately according to the length from the front to the forward limit protruding to the outside.

  As shown in FIG. 3, the needle bearing 80 includes a cylindrical outer ring 81 that rolls on the outer peripheral surface 10 a of the piston rod 10 in the axial direction (direction perpendicular to the paper surface of FIG. 3), and the inner periphery of the outer ring 81. The plurality of needle rollers 82 are arranged on the side and are rotatably supported. The needle bearing 80 is supported by a support shaft member 83. Since it is configured in this manner, the outer ring 81 can roll around the support shaft member 83 in a rotatable manner. The support shaft member 83 is inserted into a support hole formed in the pocket hole 73 inside the guide body 70a.

  In the embodiment shown in FIG. 3, the piston rod 10 has an outer peripheral surface 10 a whose cross section perpendicular to the axial direction is a substantially circular cross section. The outer ring 81 has an outer peripheral surface 81 a that is curved in a concave shape and can contact the outer peripheral surface 10 a of the piston rod 10. The curved surface that forms the outer peripheral surface 81 a has a larger radius of curvature than the curved surface that forms the outer peripheral surface of the piston rod 10.

  As shown in FIGS. 1 to 2, a plurality of through holes 71, in this example, six through holes 71 are provided in the axial direction between the circumferential directions of the guide body 70 a where the needle bearing 80 is disposed. It is formed to extend. A through bolt 72 is inserted into each of the through holes 71. An internal thread portion 42 that is screwed into the external thread portion of the through bolt 72 is formed on one side surface of the rod cover 40. By tightening and fixing the through bolt 72 to one side surface of the rod cover 40, the guide main body 70a is fixed to the rod cover 40, whereby the cylindrical guide 70 as the guide device is attached to the tube 30 as the cylinder main body. ing.

  Although not shown in FIG. 1, in the pocket hole 73 of the guide main body 70 in which the needle bearing 80 is disposed, the guide main body 70 is preferably configured to be divided by a cross section orthogonal to the axial direction. With this configuration, a plurality of divided members constituting the guide main body 70 are stacked in the axial direction, so that the long guide main body 70 according to the length of the piston rod 10 protruding outside the tube 30 is obtained. Can be easily manufactured. In addition, high precision machining is required in the axial direction for the through hole 70b, but the through hole 70b can be machined by dividing the guide main body 70 to such an extent that high precision machining is possible. It can be performed with high accuracy.

  In the fluid pressure cylinder 100 with the guide device according to the first embodiment of the present invention configured as described above, the following operational effects can be obtained.

  (1) Since the outer ring 81 is provided in the through hole 70b of the guide main body 70a so as to be in close contact with the outer peripheral surface 10a of the piston rod 10 without any gap, the piston rod 10 is axially extended from the tube 30 to the outside. Even when a load is applied to the piston rod 10 from a direction perpendicular to the axial direction when the piston rod 10 protrudes to the forward limit, the piston rod 10 does not wobble and the piston rod 10 can be moved in the axial direction. Thereby, the rectilinearity of the piston rod 10 can be improved. Therefore, it is not necessary to provide an additional guide device separately from the fluid pressure cylinder, and the straightness of the piston rod 10 can be improved. For example, the movement of the piston rod 10 itself of the fluid pressure cylinder can be When the fluid pressure cylinder 100 with a guide device of the present invention is employed in a linear motion mechanism of an automatic machine that performs caulking work, a compact linear motion guide device can be configured.

  (2) Even when a load is applied to the piston rod 10 from the direction orthogonal to the axial direction when the piston rod 10 protrudes from the tube 30 to the outside in the axial direction to the forward limit, the inside of the piston 20 and the tube 30 There is no direct contact with the wall surface, and there is little uneven wear of the U-packing 22 disposed so as to be interposed between the piston 20 and the inner wall surface of the tube 30, and internal leakage of oil is less likely to occur.

  (3) When the fluid pressure cylinder is a hydraulic cylinder, oil in the tube 30 adheres to the outer peripheral surface of the piston rod 10 every time the piston rod 10 protrudes and moves outside the tube 30. For this reason, the lubricating oil is automatically supplied to the outer ring 81 that is in close contact with the outer peripheral surface of the piston rod 10. Thereby, rolling to the axial direction of the outer ring | wheel 81 can be made smooth.

  (4) In the fluid pressure cylinder 100 with a guide device according to the first embodiment of the present invention, the inner surface of the through hole 70b of the guide body 70a has a plurality arranged in the circumferential direction in a plane orthogonal to the axial direction. The pocket holes 73 are formed in a plurality of rows in the axial direction, and the outer ring 81 of the needle bearing 80 is provided in each of the plurality of pocket holes 73 of the guide body 70a, and above the outer peripheral surface 10a of the piston rod 10. The cylindrical guide 70 further includes a support shaft member 83 that rotatably supports the outer ring 81. By configuring the guide device in this manner, the differential slip along the axial direction of the piston rod 10 is prevented so that substantially no differential slip occurs on the contact surface between the outer ring 81 and the outer peripheral surface 10a of the piston rod 10. You can guide the movement.

  (5) Moreover, in the fluid pressure cylinder 100 with a guide device of the present invention, the piston rod 10 has the outer peripheral surface 10a whose cross section orthogonal to the axial direction is a substantially circular cross section, and the outer ring 81 is the outer peripheral surface of the piston rod 10. The outer peripheral surface 81a which curves in the concave shape which can contact 10a is provided. By configuring the guide device in this manner, the contact area between the outer peripheral surface 10a of the piston rod 10 and the outer peripheral surface 81a of the outer ring 81 whose cross section orthogonal to the axial direction is a substantially circular cross section can be increased. The surface pressure of the surface can be reduced. Thereby, smooth rotation of the outer ring 81 can be ensured.

  (6) Furthermore, in the fluid pressure cylinder 100 with a guide device of the present invention, the through hole 71 into which the through bolt 72 can be inserted is formed in the guide body 70 a so as to extend in the axial direction, and the through bolt 72 is formed on the tube 30. The cylindrical guide 70 is attached to the tube 30 by being fastened and fixed to one end. By doing in this way, the guide main body 70a can be easily attached so as to be integrated with the tube 30, and the guide main body 70a can be easily detached from the tube 30.

(Embodiment 2)
FIG. 4 is a partial sectional side view partially showing a hydraulic cylinder with a guide device as another embodiment of the present invention in a longitudinal section, and FIG. 5 is seen from the direction along line VV in FIG. FIG. 6 is an enlarged partial cross-sectional view showing a part indicated by an arrow VI in FIG.

  As shown in FIGS. 4 to 6, in the fluid pressure cylinder 200 with a guide device according to the second embodiment of the present invention, the piston rod 90 has an outer peripheral surface including a plurality of flat surfaces 90a extending in the axial direction, and is a rolling element. The outer ring 84 of the needle bearing 80 is configured to have a cylindrical outer peripheral surface 84a that can contact the flat surface 90a of the piston rod 90. A cylindrical curved surface 90b is disposed between a plurality of flat surfaces 90a constituting the outer peripheral surface of the piston rod 90. A male thread portion 91 is formed at the other end of the piston rod 90. Between the outer peripheral surface of the other end of the piston rod 90 and the inner peripheral surface of the piston 20, an O-ring 92 is disposed. A male threaded portion 93 is formed at one end of the piston rod 90 so that a target member for linear movement using a fluid pressure cylinder is attached.

  In addition, the other structure in the fluid pressure cylinder 200 with a guide apparatus is the same as that of the fluid pressure cylinder 100 with a guide apparatus of Embodiment 1 shown by FIGS. 1-3.

  By configuring the guide device in this way, in addition to the operational effects (1) to (4) and (6) obtained by the fluid pressure cylinder 100 with the guide device of the first embodiment, the following operational effects are obtained. Obtainable.

  (7) Since each of the plurality of axially extending flat surfaces 90a constituting a part of the outer peripheral surface of the piston rod 90 and the cylindrical outer peripheral surface 84a of the outer ring 84 as a rolling element can be brought into contact with each other, the tube 30 It is possible to prevent the piston rod 10 protruding from the outside from rotating around the axis.

(Embodiment 3)
FIG. 7 shows still another embodiment of the present invention. FIG. 8 is a partial cross-sectional side view partially showing a hydraulic cylinder with a guide device in a longitudinal section when the piston rod is in a substantially retracted position. FIG. 6 is a partial cross-sectional side view partially showing a hydraulic cylinder with a guide device in a longitudinal section when the piston rod is in an advanced position as still another embodiment of the invention. In addition, the cross-sectional view seen from the direction along the II-II line of FIG. 7 corresponds to FIG.

  As shown in FIGS. 7 to 8, in the fluid pressure cylinder 300 with a guide device according to the third embodiment of the present invention, the piston rod 10 is a first piston rod portion disposed inside a tube 30 as a cylinder chamber. 101 and the 2nd piston rod part 102 arrange | positioned outside the tube 30, The 1st piston rod part 101 and the 2nd piston rod part 102 are couple | bonded so that attachment or detachment is possible. A male screw portion 101 a is formed at one end of the first piston rod portion 101, and a female screw portion 102 a that is screwed into the male screw portion 101 a is formed at the other end of the second piston rod portion 102.

  In addition, the other structure in the fluid pressure cylinder 300 with a guide apparatus is the same as that of the fluid pressure cylinder 100 with a guide apparatus of Embodiment 1 shown by FIGS. 1-3.

  By configuring the piston rod in this manner, the following operational effects can be obtained in addition to the operational effects (1) to (6) obtained by the fluid pressure cylinder 100 with the guide device of the first embodiment. .

  (8) The guide post in the linear motion mechanism of the automatic machine can be configured by the second piston rod portion 102. Thus, the guide post of the linear motion mechanism and the first piston rod portion 101 disposed inside the tube 30 of the fluid pressure cylinder 300 can be separated from each other. Moreover, the 1st and 2nd piston rod parts 101 and 102 can be easily integrated by couple | bonding with a screw | thread, and can also be isolate | separated easily.

(Embodiment 4)
FIG. 9 is a partial sectional side view partially showing a hydraulic cylinder with a guide device in a longitudinal section when the piston rod is in a substantially backward limit position, as another embodiment of the present invention, and FIG. FIG. 6 is a partial cross-sectional side view partially showing a fluid pressure cylinder with a guide device in a longitudinal section when the piston rod is in a forwardly advanced position as still another embodiment of the present invention.

  As shown in FIGS. 9 to 10, in the fluid pressure cylinder 400 with a guide device according to the fourth embodiment of the present invention, a retainer 720 is provided in the through hole of the guide body 710 instead of the needle bearing 80 in the second embodiment. Inserted and provided. The retainer 720 includes a roller holding cylinder 722 and a plurality of needle rollers formed in the outer peripheral surface of the roller holding cylinder 722 so that a plurality of roller holding holes are arranged in the axial direction, and held in the plurality of roller holding holes. 721. The needle roller 721 is in close contact with and in contact with a flat surface 90 a constituting a part of the outer peripheral surface of the piston rod 90, can roll on the flat surface 90 a in the axial direction, and is rotatably supported by a roller holding cylinder 722. ing. Such a retainer 720 is called a “retainer type roller guide”, and its detailed structure is described in, for example, Japanese Patent No. 3258896 and Japanese Patent No. 3601856.

  In addition, the other structure in the fluid pressure cylinder 400 with a guide apparatus is the same as that of the fluid pressure cylinder 200 with a guide apparatus of Embodiment 2 shown by FIG.

  As described above, in the fluid pressure cylinder 400 with the guide device of the present invention, the straightness of the piston rod can be improved even if the rolling elements constituting the guide device are constituted by rolling elements such as rollers inserted into the retainer 720. And the above-described effects (1) to (3), (6) and (7) can be achieved.

(Embodiment 5)
FIG. 11 is a partial sectional side view partially showing a hydraulic cylinder with a guide device in a longitudinal section when the piston rod is in a substantially retracted position as a further embodiment of the present invention. FIG. FIG. 6 is a partial cross-sectional side view partially showing a hydraulic cylinder with a guide device in a vertical cross section when a piston rod is in an advanced position as still another embodiment of the invention.

  As shown in FIGS. 11 to 12, in the fluid pressure cylinder 500 with the guide device according to the fifth embodiment of the present invention, a plurality of circulating cylinders inside the guide main body 730 are used instead of the needle bearing 80 in the first embodiment. Ball 740 is inserted and provided. The ball 740 is in close contact with the outer peripheral surface 10 a of the piston rod 10, can roll on the outer peripheral surface 10 a in the axial direction, and is rotatably supported by the guide body 730. Such a guide device is called a “circular ball guide”.

  In addition, the other structure in the fluid pressure cylinder 500 with a guide apparatus is the same as that of the fluid pressure cylinder 100 with a guide apparatus of Embodiment 1 shown by FIG.

  As described above, in the fluid pressure cylinder with a guide device of the present invention, even if it is constituted by a rolling element such as a ball circulating inside the guide main body 730, the straightness of the piston rod can be improved, and the above-described effects are obtained. (1) to (3) and (6) can be achieved.

  In Embodiment 5 described above, the ball 740 is used as the rolling element, but the guide device may be configured using a roller instead of the ball. In this case, instead of the piston rod 10, a piston rod 90 in which a part of the outer peripheral surface is a flat surface 90 a as in the second embodiment is used. At this time, the above-described operational effect (7) can be achieved. Such a guide device is called a “circulation roller guide”, and its detailed structure is described in, for example, Japanese Patent Application Laid-Open No. 2002-174236.

  In addition, you may comprise the fluid pressure cylinder with a guide apparatus by combining the component shown by the above Embodiments 1-5 variously. The fluid pressure cylinder with a guide device of the present invention can be applied to either a pneumatic cylinder or a hydraulic cylinder.

  It should be considered that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments but by the scope of the claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional side view partially showing a fluid pressure cylinder with a guide device as a first embodiment of the present invention in a vertical cross section. It is the cross-sectional view seen from the direction along the II-II line of FIG. FIG. 3 is a partially enlarged cross-sectional view showing a portion indicated by an arrow III in FIG. 2 in an enlarged manner. It is a partial cross section side view which partially shows the hydraulic cylinder with a guide apparatus as Embodiment 2 of this invention in a longitudinal cross section. It is the cross-sectional view seen from the direction along the VV line of FIG. FIG. 6 is a partially enlarged cross-sectional view showing a portion indicated by an arrow VI in FIG. 5 in an enlarged manner. FIG. 6 is a partial cross-sectional side view partially showing a fluid pressure cylinder with a guide device in a vertical cross section when a piston rod is in a substantially retracted limit position as a third embodiment of the present invention. FIG. 9 is a partial cross-sectional side view partially showing a fluid pressure cylinder with a guide device in a longitudinal section when a piston rod is in a forwardly advanced position as a third embodiment of the present invention. FIG. 10 is a partial cross-sectional side view partially showing a fluid pressure cylinder with a guide device in a vertical cross section when a piston rod is in a substantially retracted limit position as a fourth embodiment of the present invention. FIG. 10 is a partial cross-sectional side view partially showing a fluid pressure cylinder with a guide device in a longitudinal section when a piston rod is in a forwardly advanced position as a fourth embodiment of the present invention. FIG. 10 is a partial cross-sectional side view partially showing a hydraulic cylinder with a guide device in a vertical cross section when a piston rod is in a substantially retracted position as a fifth embodiment of the present invention. As Embodiment 5 of this invention, it is a partial cross section side view which shows the hydraulic cylinder with a guide apparatus in a longitudinal cross-section partially when it exists in the position which the piston rod advanced.

Explanation of symbols

  100, 200, 300, 400, 500: Fluid pressure cylinder with guide device, 10, 90: Piston rod, 10a: Outer peripheral surface, 90a: Flat surface, 20: Piston, 30: Tube, 70: Cylindrical guide, 70a, 710 730: Guide body 70b: Through hole 71: Through hole 72: Through bolt 73: Pocket hole 80: Needle bearing 81, 84: Outer ring 81a, 84a: Outer peripheral surface 83: Support shaft member 101: 1st piston rod part, 102: 2nd piston rod part, 720: Retainer, 721: Needle roller, 740: Ball.

Claims (8)

A cylinder body having a cylinder chamber formed therein;
A piston mounted so as to be capable of reciprocating in the axial direction in the cylinder chamber;
A piston rod attached to the piston and having an outer peripheral surface protruding axially outward from the cylinder body;
A guide device attached to one end of the cylinder body on the side where the piston rod enters and exits in order to guide movement along the axial direction of the piston rod protruding outward from the cylinder body;
The guide device has a guide body having a through-hole through which the piston rod can be inserted;
A rolling element provided in a through hole of the guide body, and capable of rolling in an axial direction on an outer peripheral surface of the piston rod;
A fluid pressure cylinder with a guide device, wherein the rolling element is provided in a through hole of the guide body so as to be in close contact with the outer peripheral surface of the piston rod.   A plurality of pocket holes arranged in a circumferential direction in a plane orthogonal to the axial direction are formed in the inner side surface of the through hole of the guide body in the axial direction, and the rolling elements are arranged in the guide. Provided in each of the plurality of pocket holes of the main body and capable of rolling axially on the outer peripheral surface of the piston rod, the guide device further includes a support shaft member that rotatably supports the rolling element. A fluid pressure cylinder with a guide device according to claim 1.   The piston rod has an outer peripheral surface having a substantially circular cross section perpendicular to the axial direction, and the rolling element has a concave curved outer peripheral surface that can contact the outer peripheral surface of the piston rod. 2. A hydraulic cylinder with a guide device according to 2.   The guide according to claim 2, wherein the piston rod has an outer peripheral surface including a plurality of planes extending in the axial direction, and the rolling element has a cylindrical outer peripheral surface capable of contacting the plane of the piston rod. Fluid pressure cylinder with device.   The fluid pressure cylinder with a guide device according to claim 1, wherein the rolling element is a rolling element inserted into a retainer.   The fluid pressure cylinder with a guide device according to claim 1, wherein the rolling element is a rolling element that circulates inside the guide body.   A through hole into which a through bolt can be inserted is formed in the guide body so as to extend in the axial direction, and the through bolt is fastened and fixed to one end of the cylinder body, whereby the guide device is attached to the cylinder body. The hydraulic cylinder with a guide device according to any one of claims 1 to 6, which is attached. The piston rod includes a first piston rod portion disposed in the cylinder chamber and a second piston rod portion disposed outside the cylinder chamber, and the first piston rod portion and the second piston. The fluid pressure cylinder with a guide device according to any one of claims 1 to 7, wherein the rod portion is detachably coupled.

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