JPH0525054U - Air Tenshionna - Google Patents

Abstract

(57) [Summary] [Object] To provide an air tensioner capable of stably applying a small tension to a flexible power transmission member such as a transmission rope. A movable member 20 is supported by a pair of parallel guide rods 15 fixed to a support frame 10 so as to be movable only in a reference axis C direction, and fixed to the support frame 10 coaxially with the reference axis C. The piston 35 on the inner circumference of the cylinder 31 is connected to the movable member 20 via the connecting rod 40 and ball and socket joints 45 and 46 at both ends thereof. The urging force applied to the piston 35 by the air pressure supplied from the one end side of the cylinder 31 to the piston 35 is transmitted to the movable member 20 via the guide rod 15 and the ball socket joints 45, 46, and the movable member 20. The attached tension pulley 25 presses the flexible power transmission member 53 to apply tension thereto.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tensioner that applies a tension to a flexible power transmission member such as a transmission rope, a chain, and a transmission belt, and particularly to an air tensioner that can stably apply a small tension.

[0002]

[Prior Art]

 In this type of tensioner, for example, as shown in FIG. 4, a lever 1 pivotally supported by a fixed bracket 2 and urged in one direction by a spring 4 stretched between a fixed hook 5 and the fixed hook 5. There is a rotatably supported pulley 3 at the tip of the rope. The pulley 3 is hung on the rope R between the pair of idle pulleys 6 and 6 provided on the fixed side member, and the rope 4 is urged by the spring force of the spring 4. Tension is applied to R. In this type of tensioner, instead of the spring 4, a hydraulic or pneumatic cylinder is used to apply the biasing force. Further, as shown in FIG. 5, a block 7 supported by a guide 8 formed on a fixed member is provided with a weight 9 to urge it downward and axially support the pulley 3, and the pulley 3 is hung on the rope R. Some are designed to give tension.

[0003]

[Problems to be solved by the device]

 However, in the prior art shown in FIG. 4, the biasing force applied to the pulley 3 changes according to the deflection of the spring 4. Therefore, when the pulley 3 moves over a wide range, the tension applied to the rope R also varies greatly. Become. The hydraulic or pneumatic cylinder is used, but if a constant hydraulic or pneumatic pressure is introduced from the outside, the fluctuation of tension is reduced. However, since the frictional resistance of the seal part that this type of cylinder usually has is a constant value, if the hydraulic pressure or air pressure is reduced in order to reduce the tension applied to the rope R, the effect of the frictional resistance of the seal part will be affected. It is relatively increased, which makes it impossible to stably apply a small tension to the rope. The hydraulic type also has a problem that the responsiveness deteriorates due to the viscous resistance of the hydraulic oil. The gravity type shown in FIG. 5 also reduces the fluctuation in tension, but due to the frictional resistance between the block 7 and the guide 8, it cannot stably apply a small tension like the cylinder type. Also, since this type uses the weight 9, the inertia of the moving part becomes large, the followability deteriorates, it is difficult to continuously adjust the tension value, and the tensioner mounting position and direction are also difficult to adjust. Is limited. The present invention aims to solve each of these problems.

[0004]

[Means for Solving the Problems]

 To this end, the air tensioner according to the present invention includes, as illustrated in FIGS. 1 to 3, a movable member 20 movably supported by a support frame 10 and biased in one direction, and the movable member 20. In the tensioner, which is attached and pressed by the urging force to the flexible power transmission member 53 to apply tension to the flexible power transmission member, the tensioner is positioned with respect to the support frame 10, and the reference axis line is positioned with respect to the support frame 10. A pair of guide rods 15 that are substantially symmetrical with respect to C and are arranged in parallel to each other and fixedly supported at both ends by the support frame 10, and are supported by the guide rods through axial bearings 21. The movable member 20 which is movable in the direction of the reference axis C and the movable member 20 which is attached to the support frame 10 so that the center axis of the movable member 20 is substantially aligned with the reference axis C, and a constant air pressure is supplied from one end side. And the outer diameter of the cylinder 31 which is slightly smaller than the inner diameter of the cylinder, and is slidably fitted to the inner peripheral surface of the cylinder without interposing a seal member that abuts against the inner peripheral surface of the cylinder, and is unidirectionally moved by the air pressure. The piston 35 to which a biasing force is applied and the central axis of the piston 35 are arranged so as to substantially coincide with the reference axis C, and both ends thereof are connected to the movable member 20 and the piston 35 via ball socket joints 45 and 46, respectively. It is characterized in that it is provided with a connecting rod 40 for transmitting the urging force to the movable member.

[0005]

[Action]

 Due to the constant air pressure supplied to the cylinder 31, a constant biasing force applied to the piston 35 irrespective of the stroke is applied to the movable member 20 via the ball socket joint 46, the connecting rod 40 and the ball socket joint 45. The flexible power transmission member 53 is transmitted and pressed through the pressing member 25 attached to the movable member 20 to apply tension thereto. The movable member 20 is supported by the guide rod 15 via the shaft bearing 21, and there is no seal member that causes frictional resistance between the cylinder 31 and the piston 35. Moreover, the connecting rod 40 has the center axis as a reference. Since the movable member 20 and the piston 35 are connected to each other through the ball socket joints 45 and 46 provided at both ends of the movable member 20 and the piston 35, they are arranged so as to substantially coincide with the axis C, so that the movable member 20 and the piston 35 have a friction resistance. Is not added, and therefore the frictional resistance between the guide rod 15 and the cylinder 31 supporting them is extremely small.

[0006]

[Effect of the device]

 As described above, according to the present invention, the frictional resistance between the movable member and the piston, which are the movable parts, and the guide rod and the cylinder, which are the supporting parts, is extremely small, so that the air pressure applied to the cylinder can be reduced. Even if the tension applied to the flexible power transmission member is small, the influence of the frictional resistance of these movable parts on the tension is small, and a small tension can be stably applied to the flexible power transmission member. ..

[0007]

【Example】

 The present invention will be described below with reference to the embodiments shown in FIGS. First, the overall structure will be described. The movable member 20 is supported by a pair of parallel guide rods 15 fixed to the support frame 10 so as to be movable only in the reference axis C direction. The piston 35 on the inner circumference of the cylinder 31 that is fixed to the support frame 10 is connected to the movable member 20 via the connecting rod 40 and ball and socket joints 45 and 46 at both ends thereof. The urging force applied to the piston 35 by the air pressure supplied into the cylinder 31 through the cylinder head 31a at one end of the cylinder 31 is transmitted to the movable member 20 through the guide rod 15 and the ball socket joints 45 and 46. The tension rope 25 attached to this pushes the transmission rope 53 to apply tension to it.

As shown mainly in FIGS. 1 and 2, the support frame 10 is a rectangular sheet metal member having upright portions bent on four sides. The support frame 10 has a reference axis C extending orthogonally to the centers of the front and rear standing portions 10a and 10b, and a pair of guide rods 15 symmetrical to the reference axis C and arranged parallel to each other are The front and rear ends are fitted and supported in the support holes formed in the upright portions 10a and 10b, and fixed by the retaining ring 16 so as not to come off. Four mounting screw holes 12 are formed on the bottom surface of the support frame 10. Although illustration is omitted, the mounting screw hole 12 may be formed in the upright portion of four sides instead of the bottom surface of the support frame 10.

The block-shaped movable member 20 is supported by each guide rod 15 via a pair of shaft bearings 21 provided on both sides so as to be movable only in the reference axis C direction. The shaft bearing 21 is, for example, a linear slide bearing having three rows of balls rollingly engaged with the guide rod 15. Further, stopper rubbers 17 and 18 for preventing the movable member 20 from directly contacting the standing portions 10a and 10b are provided on the outer circumferences of the front and rear ends of the respective guide rods 15.

A support shaft 22 is screwed and fixed in a screw hole 20 a formed in the movable member 20 so as to be orthogonal to the plane including the guide rods 15 on the reference axis C. A tension pulley 25 having a rope groove 25a formed on the outer periphery thereof is rotatably supported on the intermediate portion 22a of the support shaft 22 by a ball bearing 23 fixed via lock nuts 27 and 28. In this embodiment, as shown in FIG. 2, the tension pulley 25 is provided on the side opposite to the bottom surface of the support frame 10, but may be provided on the bottom surface side. The elongated hole 11 formed on the bottom surface of the support frame 10 in parallel with the reference axis C is provided for this purpose. ..

Next, the pressing cylinder device 30 will be described. The cylinder 31 of the pressing cylinder device 30 is arranged so that its central axis coincides with the reference axis C, and is fixed to the upright portion 10b of the support frame 10 by a cap 32 and a nut 33 having an escape hole in the central portion. A cylinder head 31a having a pipe joint mounting hole for supplying air pressure is fixed to the end portion on the side opposite to the movable member 20 by adhesion and caulking. An aluminum piston 35 having a piston foot 35a fixed to the movable member 20 side is slidably fitted to the inner circumference of the cylinder 31. The outer peripheral surface of the piston 35 is coated with Teflon to reduce friction, and its outer diameter is slightly smaller than the inner diameter of the cylinder 31 (for example, a radius of 5 microns). No seal member is provided.

The movable member 20 and the piston 35 are connected by a connecting rod 40, which is arranged so that its central axis coincides with the reference axis C and passes through the clearance hole of the cap 32, and ball socket joints 45 and 46 at both ends thereof. There is. The ball-and-socket joint 45 comprises a socket 45a and a ball 45b rotatably and irremovably engaged with the socket 45a. The socket 45a is screwed into the movable member 20 by a screw leg 45c and fixed by a lock nut 47, The ball 45b is formed integrally with one end of the connecting rod 40. The ball socket joint 46 is composed of a socket 46a and a ball 46b, and has substantially the same structure as the ball socket joint 45 except that the socket 46a is integrally formed with the piston foot 35a.

As shown in FIG. 3, the air tensioner of the present embodiment configured as described above is attached to the machine frame 50 of the equipment to be assembled by the four mounting screws 19 engaged with the screw holes 12. A pair of idle pulleys 52, which are fixed, are supported by the machine frame 50 via fixed shafts 51 on both sides thereof, and the rope groove 25a on the outer circumference of the tension pulley 25 pivotally supported by the movable member 20 is formed by the idle pulleys 52. It is engageable with the transmission rope 53 between. The compressed air from the compressed air source 56, which is adjusted to a constant pressure via the regulator valve 55, is supplied from the cylinder head 31a into the cylinder 31 to apply a biasing force to the piston 35 toward the movable member 20 side. The urging force is transmitted to the movable member 20 via the ball socket joint 46, the connecting rod 40 and the ball socket joint 45, and presses the tension pulley 25 against the transmission rope 53 to give tension. The regulator valve 55 controls the air pressure supplied to the cylinder 31 so as to be a constant pressure lower than the pressure of the compressed air source 56 irrespective of the movement of the piston 35, and therefore the tension applied to the transmission rope 53. Is constant. This tension can be changed by adjusting the regulator valve 55 to change the secondary pressure.

Since the movable member 20 is supported by the guide rod 15 via an axial bearing 21 such as a linear slide bearing, the frictional resistance of the movable member 20 with respect to the guide rod 15 is extremely small. Further, the air having a constant pressure supplied from the cylinder head 31a to the cylinder 31 flows out to the outside through a slight gap between the inner circumference of the cylinder 31 and the piston 35. At this time, between the cylinder 31 and the piston 35. Since a thin air layer is formed to prevent direct contact between the two members 31, 35, the frictional resistance of the piston 35 with respect to the cylinder 31 is extremely small. Further, since the connecting rod 40 is arranged such that the center axis thereof is substantially coincident with the reference axis C and the movable member 20 and the piston 35 are connected via the ball socket joints 45 and 46 provided at both ends, Side thrust and twisting do not occur on both members 20 and 35. Therefore, there is no fear that the frictional resistance of the linear slide bearing 21 will increase, or that the thin air layer between the linear slide bearing 21 and the inner circumference of the cylinder 31 will be destroyed and the piston 35 will come into direct contact with the cylinder 31 to increase the frictional resistance between them. .. As a result, the frictional resistance of the movable member 20 and the piston 35 to the guide rod 15 and the cylinder 31, which are the supporting portions, is always kept extremely small, and the secondary pressure of the regulator valve 55 is adjusted to adjust the transmission loop 53. Even when the tension applied to the movable member 20 is reduced, the influence of the frictional resistance of the movable member 20 and the piston 35 on the tension is small, and the small tension can be stably applied to the transmission rope 53.

In the above embodiment, tension is applied to the transmission rope 53 by the tension pulley 25 having the rope groove 25a, but the present invention replaces the transmission rope 53 with an arbitrary flexibility such as a chain or a transmission belt. It can be applied to a power transmission member, and a slider made of a material having a low friction coefficient can be used instead of the tension pulley 25 or the sprocket. The idle pulley 52 is not always necessary depending on the usage of the flexible power transmission member.

[Brief description of drawings]

1 is an overall plan view of an air tensioner of the present invention with a tension pulley and a support shaft removed.

2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a plan view showing a usage state of the air tensioner of the present invention.

FIG. 4 is a diagram showing an example of a conventional technique.

FIG. 5 is a diagram showing another example of the conventional technique.

[Explanation of symbols]

10 ... Support frame, 15 ... Guide rod, 20 ... Movable member,
21 ... Axial bearing (linear slide bearing), 25 ...
Pressing member (tension pulley), 31 ... Cylinder, 35
... piston, 40 ... connecting rod, 45, 46 ... ball socket joint, 53 ... flexible power transmission member (transmission rope), C ... reference axis.

Claims (1)

[Scope of utility model registration request] 1. A movable member, which is movably supported by a support frame and is applied with an urging force in one direction, and a flexible member which is attached to the movable member and is pressed by a flexible power transmission member by the urging force. In a tensioner composed of a pressing member that applies tension to the sexual power transmission member, the tensioner is arranged substantially symmetrically with respect to a reference axis positioned with respect to the support frame and parallel to each other, and both ends thereof are fixedly supported by the support frame. A pair of guide rods, the movable members supported by the guide rods via axial bearings and movable in the direction of the reference axis, and the center axis of the movable member is substantially aligned with the reference axis. A cylinder that is attached to a support frame and is supplied with a constant air pressure from one end side, and a cylinder that has an outer diameter slightly smaller than the inner diameter of this cylinder A piston, which is slidably fitted to the inner peripheral surface and is biased in one direction by the air pressure, is arranged so that its central axis is approximately coincident with the reference axis, and both ends are respectively connected through ball socket joints. An air tensioner comprising a connecting rod connected to the movable member and the piston to transmit the urging force to the movable member.