JP2011007282A - Trunnion type gas spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trunnion type gas spring having high rigidity of a trunnion shaft periphery even with a compact structure, capable of maintaining high squareness, and having superior durability.SOLUTION: The trunnion type gas spring 1 includes a cylinder body 2, a gas containing chamber 3 formed in the cylinder body 2 and containing compressed gas, a piston part 5 receiving gas pressure of the compressed gas of the gas containing chamber 3, a piston rod 6 extending from the piston part 5 to an exterior of the cylinder body 2, and a trunnion shaft member 10 provided in the cylinder body 2. The trunnion shaft member 10 includes: a trunnion shaft body 21 having an axis 21a orthogonal to an axis 6a of the piston rod 6, provided so as to pierce the cylinder body 2 and the gas containing chamber 3, and joined with the cylinder body 2; a pair of trunnion shafts 22 integrally projecting from both ends of the trunnion shaft body 21; and a through-hole 23 formed in the trunnion shaft body 21 and inserted with the piston rod 6 so as to freely reciprocate.

Description

  The present invention relates to a trunnion-type gas spring, and more particularly to a trunnion-type gas spring having a trunnion shaft that can swingably be supported on various machine devices such as machine tools and robots.

  2. Description of the Related Art Conventionally, various machine devices such as machine tools and robots are sometimes equipped with trunnion-type hydraulic cylinders to assist with workpiece processing, product conveyance, and the like. A trunnion shaft having an axis perpendicular to the axis of the cylinder body is provided on an outer peripheral portion of a predetermined portion of the cylinder body in order to swingably support the cylinder body of the fluid pressure cylinder with respect to various mechanical devices. . This trunnion type hydraulic cylinder is already known from various documents.

  For example, in the trunnion type hydraulic cylinder described in Patent Document 1, a ring-shaped trunnion guide is externally fitted on the outer periphery of a cylinder tube and integrally joined by welding, and a pair of trunnions is formed on the outer periphery of the trunnion guide. A trunnion body provided on the outer peripheral portion facing the pin shaft is inserted and fixed to the trunnion guide by a plurality of bolts and stopper members.

  As shown in FIGS. 6 to 9, trunnion type fluid pressure cylinders 31 and 41 having a configuration different from the configuration of Patent Document 1 are put into practical use. In the fluid pressure cylinder 31 of Conventional Example 1 shown in FIGS. 6 and 7, a trunnion shaft member 33 formed integrally with a pair of trunnion shafts 34 and a ring-shaped trunnion shaft body 35 is attached to the cylinder body 32. It is fitted and welded. The trunnion shaft member 33 is substantially equivalent to a trunnion guide and a trunnion body of Patent Document 1 which are integrally formed and a plurality of bolts and stopper members are omitted.

  In the fluid pressure cylinder 41 of Conventional Example 2 shown in FIGS. 8 and 9, a pair of groove portions 42 a is formed on the outer peripheral portion of the cylinder body 42, and a trunnion shaft member 43 having a pair of trunnion shafts 44 is replaced with a pair of trunnion shaft members 43. Each groove portion 42a is positioned and welded to be orthogonal to the axis of the cylinder body 42.

Japanese Patent Laid-Open No. 11-82422

  However, in the trunnion type hydraulic cylinder of Patent Document 1, the number of components for configuring the trunnion shaft in the cylinder body increases, and it takes time to assemble these components into the cylinder body. It will increase. Further, in the configuration of the trunnion shaft, a plurality of components are assembled on the outer peripheral portion of the cylinder body, so that the cylinder body is enlarged in the radial direction.

  In the trunnion shaft member of Conventional Example 1, it is necessary to form a ring-shaped trunnion shaft body having a diameter larger than the outer diameter of the cylinder body and a pair of trunnion shafts by cutting from a single plate-like member. . However, since the amount of cutting increases, the manufacturing cost increases. Since the trunnion shaft member is formed to have a larger diameter than the outer diameter of the cylinder body, as in the case of Patent Document 1, the fluid pressure cylinder is enlarged in the radial direction.

  In the trunnion shaft member of Conventional Example 2, the pair of trunnion shafts are positioned in the groove of the cylinder body and then welded to the cylinder body. However, in this trunnion shaft, since the two members must be aligned and positioned with respect to the cylinder body, the perpendicularity between the axis of the trunnion shaft and the axis of the cylinder body is accurately set. It is difficult. Since this pair of trunnion shafts is only welded to the groove on the outer peripheral portion of the cylinder body, when a large load is applied to the trunnion shaft, the above-mentioned squareness collapses due to elastic deformation of the cylinder body, and the durability deteriorates. There is a risk of it.

  An object of the present invention is to provide a trunnion-type gas spring that has a compact configuration, has high rigidity around the trunnion shaft, can maintain a high squareness, and has excellent durability.

  The trunnion-type gas spring according to claim 1 is capable of receiving the pressure of the compressed gas in the gas storage chamber by being installed in the cylinder main body, the gas storage chamber formed in the cylinder main body for storing the compressed gas, and the cylinder main body. A trunnion-type gas spring having a piston portion, a piston rod extending from the piston portion to the outside of the cylinder body, and a trunnion shaft member provided on the cylinder body, wherein the trunnion shaft member is orthogonal to the axis of the piston rod A trunnion shaft main body that has a shaft center that extends through the cylinder main body and the gas storage chamber and is coupled to the cylinder main body, and a pair of trunnion shafts that project integrally from both ends of the trunnion shaft main body A through hole formed in the trunnion shaft main body through which the piston rod is inserted so as to move forward and backward. It is a symptom.

  The trunnion type gas spring of claim 2 is characterized in that, in the invention of claim 1, the vicinity of both ends of the trunnion shaft main body is welded to the cylinder main body over the entire circumference.

  According to a third aspect of the present invention, the trunnion type gas spring according to the first aspect of the present invention is characterized in that an outer diameter of the trunnion shaft main body is smaller than an inner diameter of the cylinder main body.

  A trunnion type gas spring according to a fourth aspect of the present invention is the gas spring according to any one of the first to third aspects, wherein the piston portion receives the gas pressure in the gas storage chamber and biases the piston rod in the retracted direction. A pull-type gas spring, in which a piston sliding hole is formed in the cylinder body, in which the piston portion can slide in a gas-tight manner, and the piston portion advanced to the maximum is received at the end of the piston sliding hole. A restricting portion is formed, and the trunnion shaft member is provided in a portion of the cylinder body that is closer to the piston rod than the restricting portion.

  A trunnion type gas spring according to a fifth aspect of the present invention is the gas spring according to any one of the first to third aspects, wherein the piston portion receives the gas pressure in the gas storage chamber and urges the piston rod in the forward direction. The push-type gas spring is formed with a restricting portion for receiving the piston portion that has been advanced to the maximum inside the cylinder body, and the trunnion shaft member is located on the piston rod advancing side of the restricting portion of the cylinder body. It is characterized by being provided.

  According to the invention of claim 1, the trunnion shaft main body of the trunnion shaft member is provided with the cylinder main body and the gas storage chamber in a penetrating manner and coupled to the cylinder main body, so that the cylinder main body is reinforced with the trunnion shaft member. Therefore, the rigidity of the cylinder body cylinder and the rigidity around the trunnion shaft member are increased. And since there is no possibility that the cylinder body cylinder part or the trunnion shaft member is elastically deformed by the load acting on the trunnion shaft member, the perpendicularity between the shaft center of the trunnion shaft member and the axis of the cylinder body is maintained high, and the trunnion support The durability of the structure can be increased.

  In addition, since the trunnion shaft main body of the trunnion shaft member does not protrude significantly from the outer peripheral portion of the cylinder main body, a compact trunnion type gas spring can be obtained. Since the trunnion shaft member can be manufactured by cutting one shaft-shaped member, the number of components can be reduced and the number of cutting parts can be reduced, so that the manufacturing cost can be reduced.

According to the invention of claim 2, since the vicinity of both ends of the trunnion shaft main body is welded and joined to the cylinder main body over the entire circumference, the rigidity of the cylinder main body cylindrical portion and the rigidity around the trunnion shaft member are further increased. In addition, the compressed gas can be reliably sealed in a gas tight manner.
According to the invention of claim 3, since the outer diameter of the trunnion shaft main body is smaller than the inner diameter of the cylinder main body, the cylinder main body is maintained without being divided by the trunnion shaft main body. The linearity of can be ensured.

  According to the invention of claim 4, the gas spring is a pull-type trunnion type because the piston portion receives the gas pressure in the gas storage chamber and urges the piston rod in the retracting direction. A gas spring is obtained. A piston sliding hole in which the piston can slide in a gas-tight manner is formed inside the cylinder body, and a restricting portion for receiving the piston portion advanced to the maximum at the end of the piston sliding hole is formed. Since it was provided in the part of the cylinder body on the piston rod advancement side relative to the restriction part, the piston part advanced as much as possible was received by the restriction part, and was provided in the part on the piston rod advancement side from this restriction part The piston portion does not interfere with the trunnion shaft member.

  According to the invention of claim 5, the gas spring is a push type gas spring in which the piston portion receives the gas pressure in the gas storage chamber and urges the piston rod in the forward direction. A spring is obtained. A restricting portion for receiving the piston portion that has been advanced to the maximum extent inside the cylinder body is formed, and the trunnion shaft member is provided at a position closer to the piston rod than the restricting portion of the cylinder body, so that the piston that has advanced to the maximum extent is provided. The portion is received by the restricting portion, and the piston portion does not interfere with the trunnion shaft member provided in the portion closer to the piston rod than the restricting portion.

It is a cross-sectional view of the trunnion type gas spring according to the embodiment of the present invention. It is a side view of a trunnion type gas spring. It is the III-III sectional view taken on the line of FIG. 6 is a cross-sectional view of a trunnion type gas spring according to Embodiment 2. FIG. 6 is a cross-sectional view of a trunnion type gas spring according to Embodiment 3. FIG. It is a cross-sectional view of a trunnion type gas spring according to Conventional Example 1. It is a longitudinal cross-sectional view of a trunnion type gas spring. It is a cross-sectional view of a trunnion type gas spring according to Conventional Example 2. It is a longitudinal cross-sectional view of a trunnion type gas spring.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

First, the overall configuration of the trunnion type gas spring 1 will be described.
As shown in FIGS. 1 to 3, the trunnion type gas spring 1 includes a cylinder body 2, a gas storage chamber 3 in the cylinder body 2, a piston portion 7, and a piston extending from the piston portion 7 to the outside of the cylinder body 2. For example, a rod 6, a clevis joint 8 for connecting the gas spring 1 to a movable member that swings and moves in a mechanical device (not shown), a trunnion shaft member 10 for supporting the gas spring 1 to the mechanical device, and the like. It is configured. 1 and 2 will be described as the front, and the right will be described as the rear.

  The trunnion type gas spring 1 can be swingably supported with respect to the mechanical device via the trunnion shaft member 10 as a balancer device of various mechanical devices such as a robot and a machine tool. The front end portion of the piston rod 6 is connected to the movable member of the mechanical device via the clevis joint 8, and the biasing force that balances the weight and moment acting on the movable member is applied by the biasing force of the compressed gas of the gas spring 1. Assist the movable member. The gas spring 1 is biased in a direction in which the piston portion 7 retracts into the cylinder body 2 by a compressed gas (for example, a compressed nitrogen gas of 5 to 15 MPa) filled in the gas storage chamber 3 in the cylinder body 2. Pull type gas spring.

Next, the cylinder body 2 will be described.
As shown in FIGS. 1 to 3, the cylinder body 2 includes a gas storage chamber 3, an atmosphere release chamber 4, a steel cylindrical member 11, and a steel member that blocks the front end portion and the rear end portion of the cylindrical member 11. Rod side end wall portion 12, head side end wall portion 13, small-diameter cylinder hole 11 a and piston sliding hole 14 formed in the cylinder body 2, and restricting portion 15 for receiving the piston portion 7 in the maximum forward state. Etc.

  The rod side end wall portion 12 has a through hole 16, and the piston rod 6 is inserted into the through hole 16 so as to be slidable in the front-rear direction. An annular seal member 12 a that seals gas tightly between the cylindrical member 11 is mounted on the outer peripheral portion of the rod-side end wall portion 12. An annular seal member 12b that gas-tightly seals a sliding gap between the rod side end wall portion 12 and the piston rod 6 and a synthetic resin or metal guide ring that guides the piston rod 6 12c and a dust seal 12d for preventing dust and dust from entering from the outside.

  As shown in FIG. 1, a small hole 13 a is formed in the head side end wall portion 13, and this small hole 13 a brings the air release chamber 4 behind the piston portion 7 inside the cylinder body 2 into an air open state. be able to. When the piston portion 7 is retreated to the maximum by the urging force of the compressed gas in the gas storage chamber 3, the annular locked portion 5d at the rear end portion of the piston member 5 of the piston portion 7 becomes the head side end wall. The front end of the portion 13 is in contact with the annular locking portion 13b.

  The piston sliding hole 14 is provided in the rear portion of the cylindrical member 11. The piston sliding hole 14 is polished into a mirror surface so that the piston portion 7 can slide in a gas-tight manner. The small diameter cylinder hole 11 a is provided in a portion of the cylindrical member 11 other than the piston sliding hole 14, and the inner diameter of the small diameter cylinder hole 11 a is slightly smaller than the inner diameter of the piston sliding hole 14.

  The restricting portion 15 is formed at the front end of the piston sliding hole 14 at the boundary between the small diameter cylinder hole 11 a of the cylinder body 2 and the piston sliding hole 14. The restricting portion 15 receives the outer peripheral portion of the front end surface of the piston member 5 that has advanced to the maximum. The restricting portion 15 defines the stroke range of the piston portion 7. The moving stroke range of the piston portion 5, that is, the range of the piston sliding hole 14 can be variously set at the design stage according to specifications.

Next, the gas storage chamber 3 will be described.
As shown in FIG. 1, the gas storage chamber 3 includes a piston sliding hole 14 and a small-diameter cylinder hole 11 a in front of the piston portion 7 in the cylinder body 2. However, when the piston portion 7 is advanced to the maximum extent, the gas storage chamber 3 is only the small-diameter cylinder hole 11a portion in the cylinder body 2. The gas storage chamber 3 is formed inside the cylinder body 2 and stores compressed gas. The gas storage chamber 3 is filled with a compressed gas through a gas filling hole 17 provided in the rod side end wall portion 12 and a gas filling valve 18 attached to the gas filling hole 17. In addition, the volume of the gas storage chamber 3 can be variously set at the design stage according to specifications.

Next, the piston part 7 will be described.
As shown in FIG. 1, the piston portion 7 includes a piston member 5 and a rear end side connecting portion 6 b of the piston rod 6. The piston member 5 is fitted in the cylinder sliding hole 14 in a gas-tight and slidable manner, and is screwed into the connecting portion 6 b of the piston rod 6. The piston portion 7 receives the gas pressure of the compressed gas in the gas storage chamber 3 at the annular pressure receiving surface at the front end of the piston member 5. An annular seal member 5 a that seals the space between the piston rod 6 and the piston rod 6 in a gas tight manner is attached to the inner peripheral portion of the piston member 5. On the outer periphery of the piston member 5, an annular seal member 5 b that seals the space between the cylindrical member 11 and a synthetic resin or metal guide ring 5 c that guides the piston member 5 is mounted.

Next, the piston rod 6 will be described.
As shown in FIGS. 1 and 3, the piston rod 6 passes through the gas storage chamber 3, and from the piston portion 7, a through hole 23 of a trunnion shaft member 10 described later and a rod side end wall portion 12 of the cylinder body 2. The through hole 16 is inserted and extended to the outside. The surface of the piston rod 6 is polished into a mirror surface so that compressed gas does not leak from the sliding gap between the cylinder body 2 and the piston rod 6. A clevis joint 8 is screwed into the front end side connecting portion 6 c of the piston rod 6.

Next, the clevis joint 8 will be described.
As shown in FIGS. 1 and 2, the clevis joint 8 is provided at the front end portion of the piston rod 6 and is connected to a movable member which is a component of a machine device such as a machine tool or a robot (not shown). When this movable member is oscillated, for example, the piston rod 6 is moved forward and backward with respect to the cylinder body 2, and the urging force is applied to the movable member by the urging force of the compressed gas, so that the movable member oscillates. Assist exercise.

Here, the trunnion shaft member 10 will be described.
As shown in FIGS. 1 to 3, the trunnion shaft member 10 includes a trunnion shaft main body 21, a pair of trunnion shafts 22 formed on the trunnion shaft main body 21, and a through hole that is orthogonal to the axis 21 a of the trunnion shaft main body 21. It has a hole 23 and the like. The trunnion shaft member 10 is mounted in a penetrating manner in a mounting hole 24 formed in a penetrating manner in the vicinity of the restricting portion 15 of the small diameter cylinder hole 11 a of the cylinder body 2. The mounting hole 24 is accurately formed so that the axis of the mounting hole 24 is orthogonal to the axis of the cylinder body 2. The trunnion shaft member 10 is provided in a portion of the cylinder body 2 on the piston rod 6 advancement side with respect to the restriction portion 15.

Next, the trunnion shaft main body 21 will be described.
The trunnion shaft main body 21 is made of a steel columnar member, has a shaft center 21a orthogonal to the shaft center 6a of the piston rod 6, and has a cylinder body 2 and a gas storage chamber 3 provided in a penetrating manner. Yes. The length of the trunnion shaft body 21 in the longitudinal direction is formed slightly longer than the diameter of the cylinder body 2. The vicinity of both ends of the trunnion shaft main body 21 is welded and joined to the cylinder main body 2 over the entire circumference thereof, and the compressed gas in the gas storage chamber 3 is hermetically sealed. The outer diameter of the trunnion shaft main body 21 is smaller than the inner diameter of the cylinder main body 2 and larger than the outer diameter of the piston rod 6.

Next, the pair of trunnion shafts 22 will be described.
The pair of trunnion shafts 22 are formed so as to protrude integrally from both ends of the trunnion shaft main body 21. The axis 21a of the trunnion shaft main body 21 and the axis of the pair of trunnion shafts 22 are set concentrically or substantially concentrically. The diameter of the pair of trunnion shafts 22 is about ½ of the diameter of the trunnion shaft main body 21, but it is not particularly limited to this size. By connecting the pair of trunnion shafts 22 to a pair of shaft support portions of a mechanical device (not shown), the trunnion-type gas spring 1 is swingably mounted.

Next, the through hole 23 formed in the trunnion shaft main body 21 will be described.
As shown in FIG. 1, the through hole 23 is formed at the center of the trunnion shaft main body 21 so as to be orthogonal to the axis 21 a of the trunnion shaft main body 21. The piston rod 6 is inserted into the through hole 23 so as to be movable forward and backward. The diameter of the through hole 23 is slightly larger than the diameter of the piston rod 6. For this reason, a slight gap is formed between the outer peripheral surface of the piston rod 6 and the through hole 23 so that the piston rod 6 does not contact the trunnion shaft main body 21. After the trunnion shaft main body 21 of both ends of the trunnion shaft main body 21 is welded to the cylinder main body 2, the surface of the trunnion shaft 22 may be polished or cut as necessary. Finally, the gas storage chamber 3 is filled with compressed gas from the gas filling valve 18.

Next, the operation and effect of the trunnion type gas spring 1 will be described.
First, when the gas spring 1 is mounted as a balancer device in a mechanical device (not shown), a pair of trunnion shafts 22 of the trunnion shaft member 10 are connected to a pair of shaft support portions of the mechanical device, and a cylinder The main body 2 is swingably attached to the mechanical device, and the clevis joint 8 is connected to the movable member.

  Next, when the mechanical device is in operation, the gas spring 1 swings following the swing of the movable member about the pair of trunnion shafts 22 as the swing center by the swinging motion of the movable member, and is passed through the clevis joint 8. Thus, the piston rod 6 moves forward and backward with respect to the cylinder body 2. At this time, the gas spring 1 acts to maintain the movable member in a balanced state by the urging force of the compressed gas in the gas storage chamber 3, and assists the swinging operation of the movable member. In addition, in the state which the piston part 7 advanced to the maximum, since it contacts the control part 15, the piston part 7 does not contact the trunnion shaft member 10. When the piston part 7 is retracted to the maximum, the piston part 7 contacts the head side end wall part 13.

  The trunnion shaft main body 21 of the trunnion shaft member 10 is provided so as to pass through the cylindrical member 11 of the cylinder main body 2 and the gas storage chamber 3 and is coupled to the cylindrical member 11 of the cylinder main body 2. Thus, since the cylindrical member 11 is reinforced, the rigidity of the cylindrical member 11 of the cylinder body 2 and the rigidity around the trunnion shaft member 10 are increased. And since there is no possibility that the cylindrical member 11 or the trunnion shaft member 10 is elastically deformed by the load acting on the trunnion shaft member 10, the perpendicularity between the shaft center of the trunnion shaft member 10 and the shaft center of the cylinder body 2 is maintained high. The durability of the trunnion support structure can be increased.

Since the vicinity of both ends of the trunnion shaft main body 21 is welded to the cylinder main body 2 over the entire circumference, the rigidity of the cylindrical member 11 of the cylinder main body 2 and the rigidity of the periphery of the trunnion shaft member 10 are further increased and compressed reliably. Gas can be sealed gas tightly.
In addition, since the trunnion shaft main body 21 of the trunnion shaft member 10 does not protrude greatly from the outer peripheral portion of the cylinder main body 2, a compact trunnion type gas spring 1 can be obtained. Since the trunnion shaft member 21 can be manufactured by cutting one shaft-like member, the number of components can be reduced and the number of cutting parts can be reduced, so that the manufacturing cost can be reduced.

  Since the outer diameter of the trunnion shaft main body 21 is smaller than the inner diameter of the cylinder main body 2, the cylinder main body 2 is not divided by the trunnion shaft main body 21, and maintains its integrity, and the linearity of the axis of the cylinder main body 2 is maintained. Can be secured.

  A piston sliding hole 14 through which the piston 6 can slide in a gas-tight manner is formed inside the cylinder body 2, and a restricting portion 15 for receiving the piston portion 7 that has advanced to the maximum is formed at the end of the piston sliding hole 14. Since the trunnion shaft member 10 is provided in a portion of the cylinder body 2 on the piston rod 6 advancement side with respect to the restricting portion 15, the piston portion 7 that has advanced to the maximum is received by the restricting portion 15. The piston does not interfere with the trunnion shaft member 10 provided at a position closer to the piston rod 6 than 15.

The gas spring 1 is a pull-type gas spring in which the piston portion 7 receives the gas pressure in the gas storage chamber 3 and urges the piston rod 6 in the retracting direction, so that a pull-type trunnion-type gas spring 1 is obtained. It is done.
Since the clevis joint 8 is provided at the front end of the piston rod 6, the piston rod 6 can be connected to a movable member of various mechanical devices, and can be equipped in various mechanical devices.

Next, a gas spring 1A according to Example 2 in which the trunnion type gas spring 1 of Example 1 is partially changed will be described with reference to FIG. However, the same constituent elements as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different constituent elements will be described.
In this gas spring 1A, a gas storage chamber 4A communicating with the gas storage chamber 3A is provided instead of the atmosphere release chamber 4. The gas spring 1A is a push-type gas spring that is urged in a direction in which the piston portion 7A moves forward out of the cylinder body 2A by the compressed gas filled in the gas storage chambers 3A and 4A in the cylinder body 2A.

  3 A of gas storage chambers are comprised by the piston sliding hole 14 and the small diameter cylinder hole 11a ahead from piston part 7A inside cylinder main body 2A. However, when the piston portion 7A is in the maximum advanced state, the gas storage chamber 3A is only the small-diameter cylinder hole 11a portion in the cylinder body 2A. 4 A of gas storage chambers are comprised by the piston sliding hole 14 back from the piston part 7A inside the cylinder main body 2A, and the opening hole 13c of the head side end wall part 13A. However, when the piston portion 7A is in the fully retracted state, the locked portion 5d of the piston member 5A of the piston portion 7A is in contact with the locking portion 13b of the head side end wall portion 13A, and the gas storage chamber 4A is a cylinder. It becomes only the opening hole 13c portion in the main body 2A.

  The piston portion 7 </ b> A includes a piston member 5 </ b> A and a rear end side connecting portion 6 b of the piston rod 6. The piston member 5 </ b> A is slidably mounted in the piston sliding hole 14 and is screwed into the connecting portion 6 b of the piston rod 6. The piston member 5A is provided with a plurality of through holes 5e in the direction of the axis 6a of the piston rod 6, and communicates the gas storage chamber 3A and the gas storage chamber 4A. An annular seal member 13d that seals between the cylindrical member 11 and the cylinder member 11 is attached to the outer peripheral portion of the head side end wall portion 13A. The annular seal member 5b of the piston member 5A and the small hole 13a of the head side end wall portion 13A are omitted.

The gas storage chambers 3 </ b> A and 4 </ b> A are filled with compressed gas through a gas filling hole 17 provided in the rod side end wall portion 12 and a gas filling valve 18 attached to the gas filling hole 17.
In the piston portion 7A, the gas pressure of the compressed gas in the gas storage chamber 3A is received by the annular pressure receiving surface at the front end, and the gas pressure of the compressed gas in the gas storage chamber 4A is received by the pressure receiving surface at the rear end. Since the piston rod 6 is larger in cross-sectional area than the annular pressure receiving surface at the front end, the piston portion 7A is urged in the direction of advancing out of the cylinder body 2A by the urging force of the compressed gas.

The gas spring 1A is a push-type gas spring in which the piston portion 7A receives the gas pressure in the gas storage chambers 3A and 4A and urges the piston rod 6 in the forward direction. Therefore, the push-type trunnion-type gas spring 1A can get. A restricting portion 15 for receiving the piston portion 7A that has advanced to the maximum extent is formed inside the cylinder body 2A, and the trunnion shaft member 21 is provided in a portion of the cylinder body 2A that is closer to the piston rod 6 than the restricting portion 15 is. Therefore, the piston portion 7A that has advanced as much as possible is received by the restricting portion 15, and the piston portion 7A does not interfere with the trunnion shaft member 21 that is provided at a position closer to the piston rod 6 than the restricting portion 15.
Since other operations and effects are the same as those of the first embodiment, description thereof will be omitted.

Next, a gas spring 1B according to Example 3 in which the trunnion type gas spring 1A according to Example 2 is partially changed will be described with reference to FIG. However, the same constituent elements as those in the second embodiment are denoted by the same reference numerals, description thereof is omitted, and only different constituent elements are described.
In this gas spring 1B, instead of the piston portion 7A, the guide ring 5c, the plurality of through holes 5e, etc. are omitted, and a simplified piston portion 7B is integrally formed at the rear end portion of the piston rod 6B. Yes. The gas spring 1B is a push-type gas spring that is urged in a direction in which the piston portion 7B moves forward out of the cylinder body 2B by the compressed gas filled in the gas storage chambers 3B and 4B in the cylinder body 2B.

  The gas storage chamber 3B includes a cylinder hole 14B, a boundary cylinder hole 11b, and a small-diameter cylinder hole 11a in front of the piston 7B in the cylinder body 2B. However, when the piston portion 7B is in the maximum advanced state, the gas storage chamber 3B is only the boundary cylinder hole 11b and the small diameter cylinder hole 11a portion in the cylinder body 2. The gas storage chamber 4B is configured by a cylinder hole 14B behind the piston portion 7B and an opening hole 13c in the head side end wall portion 13A in the cylinder body 2B. However, when the piston portion 7B is maximally retracted, the locked portion 5d of the piston portion 7B is brought into contact with the locking portion 13b of the head side end wall portion 13A, so that the gas storage chamber 4B is located inside the cylinder body 2B. Of these, only the opening hole 13c is provided.

  The piston portion 7B has an outer diameter smaller than the inner diameter of the cylinder hole 14B of the cylinder body 2B and larger than the inner diameter of the boundary portion cylinder hole 11b. Thereby, a slight gap is formed between the inner periphery of the cylinder body 2B and the outer periphery of the piston portion 7B, and the gas storage chamber 3B and the gas storage chamber 4B are communicated with each other. In addition, you may comprise so that several groove | channels may be intermittently formed in the axial center 6a direction of piston rod 6B on the outer periphery of piston part 7B, and gas storage chamber 3B and gas storage chamber 4B may be connected. At this time, the piston member 7B may be slidably mounted in the cylinder hole 14B.

  In the cylindrical member 11B, the boundary cylinder hole 11b provided between the small diameter cylinder hole 11a and the cylinder hole 14B is formed to have a smaller diameter than the small diameter cylinder hole 11a. The restricting portion 15B is formed at the front end portion of the cylinder hole 14B at the boundary portion between the boundary portion cylinder hole 11b and the cylinder hole 14B. The restricting portion 15B receives the outer peripheral portion of the front end surface of the piston portion 7B that has advanced to the maximum. The inner diameter of the cylinder hole 14B is substantially the same as that of the piston sliding hole 14 of the first and second embodiments.

In the piston portion 7B, the gas pressure of the compressed gas in the gas storage chamber 3B is received by the annular pressure receiving surface at the front end, and the gas pressure of the compressed gas in the gas storage chamber 4B is received by the flat pressure receiving surface at the rear end. Since the pressure receiving surface is wider than the annular pressure receiving surface at the front end by the integral of the longitudinal section of the piston rod 6B, the piston portion 7B is urged in the direction of advancing out of the cylinder body 2B by the urging force of the compressed gas.
Since other operations and effects are the same as those of the second embodiment, description thereof will be omitted.

Next, a modified example in which the first to third embodiments are partially changed will be described.
[1] In the first to third embodiments, the trunnion shaft member 10 is provided in the vicinity of the restricting portion 15 of the small diameter cylinder hole 11a of the cylinder body 2, but the trunnion shaft member 10 is arranged in the length direction of the small diameter hole 11a. The central portion of the cylinder body 2 may be provided near the rod-side end wall portion 12, and the portion of the cylinder body 2 where the trunnion shaft member 10 is provided is a small diameter cylinder hole 11a. Various parts can be changed at the design stage according to the specifications.
[2] In the first to third embodiments, the trunnion shaft main body 21 is welded to the cylinder main body 2. However, the invention is not particularly limited to this, and the trunnion shaft is formed using a nut, a bolt, a spacer, a seal member, or the like. The main body may be coupled to the cylinder main body and sealed gas tightly, or may be configured to be coupled using various other coupling means.
[3] In the first to third embodiments, the trunnion shaft main body 21 is formed in a cylindrical shape, but may be formed in a prismatic shape.
[4] In addition, various modifications may be added to the above-described embodiment without departing from the spirit of the present invention.

  The trunnion type gas spring of the present invention can be used for a balancer device of various machine devices such as machine tools and robots, and for other applications.

1, 1A, 1B Trunnion type gas spring 2, 2A, 2B Cylinder body 3, 3A, 3B Gas storage chamber 4 Atmospheric release chamber 4A, 4B Gas storage chamber 5, 5A Piston member 6, 6B Piston rod 7, 7A, 7B Piston Part 8 clevis joint 10 trunnion shaft member 14 piston sliding holes 15 and 15B restricting part 21 trunnion shaft main body 22 trunnion shaft 23 through hole

Claims (5)

A cylinder body, a gas storage chamber formed in the cylinder body and containing compressed gas, a piston portion mounted in the cylinder body and capable of receiving the gas pressure of the compressed gas in the gas storage chamber, and a cylinder from the piston portion In a trunnion type gas spring having a piston rod extending to the outside of the main body and a trunnion shaft member provided in the cylinder main body,
The trunnion shaft member is
A trunnion shaft main body having an axis perpendicular to the axis of the piston rod and provided in a penetrating manner with the cylinder main body and the gas storage chamber;
A pair of trunnion shafts integrally projecting from both ends of the trunnion shaft body;
A trunnion-type gas spring comprising a through-hole formed in the trunnion shaft main body and through which the piston rod is inserted so as to be movable back and forth.   The trunnion-type gas spring according to claim 1, wherein the vicinity of both ends of the trunnion shaft main body is welded and joined to the cylinder main body over the entire circumference.   The trunnion type gas spring according to claim 1, wherein an outer diameter of the trunnion shaft main body is smaller than an inner diameter of the cylinder main body. The gas spring is a pull-type gas spring in which the piston portion receives the gas pressure in the gas storage chamber and urges the piston rod in the retracted direction.
A piston sliding hole is formed in the cylinder body so that the piston portion can slide in a gas-tight manner, and a restricting portion for receiving the piston portion advanced to the maximum at the end of the piston sliding hole is formed. The trunnion type gas spring according to any one of claims 1 to 3, wherein the shaft member is provided in a portion of the cylinder body that is closer to the piston rod than the restricting portion. The gas spring is a push-type gas spring in which the piston portion receives the gas pressure in the gas storage chamber and biases the piston rod in the forward direction.
A restricting portion for receiving a piston portion that has been advanced to the maximum inside the cylinder body is formed, and the trunnion shaft member is provided in a portion of the cylinder body that is closer to the piston rod than the restricting portion. The trunnion type gas spring according to any one of claims 1 to 3.