JP2647678B2 - Spindle type bolt / nut durability tester - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a testing machine for testing the durability of a spindle-type bolt / nut by reciprocating it under a load.

(Prior Art) Conventionally, a device for testing the durability of a spindle-type bolt / nut by reciprocating it in a loaded state is capable of reciprocating in parallel with the spindle through a joint with a nut screwed to the spindle via a joint. The nut and the load rod are reciprocated by connecting the load rod to springs at both ends of the load rod and rotating the spindle. A load is applied to the nut by the spring force generated at this time.

This type of device applies a load to the nut due to the deformation of the spring due to the reciprocating movement of the nut. However, due to the characteristics of the spring, the resilient force changes in proportion to the amount of deformation, so that the spring acts on the nut depending on the position of the nut. It is difficult to perform a load durability test uniformly over the entire stroke. In addition, since the spring has an inherent spring constant, when the set load to be applied is changed, it is necessary to replace the spring with a new spring corresponding to the set load after the change, which complicates the operation.

(Problems to be solved by the present invention) The present invention solves such a conventional inconvenience, and can reciprocate the nuts of the spindle-type bolts and nuts under a uniform load state, and easily change the set load. It is another object of the present invention to provide a spindle-type bolt / nut durability tester capable of simultaneously rotating the plurality of spindles under the same conditions.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a durability test machine which rotates a bolt of a spindle type bolt / nut to reciprocate the nut under a load state. A drive device that has a plurality of support devices each comprising a set of support portions that rotatably support both ends, and that is connected to one end of each spindle supported by each support device and rotates them simultaneously. A load device that applies a load according to the movement of each nut that is screwed to each spindle and moves by the rotation of each spindle, the load device being a load cylinder,
A load rod connected to a piston rod of the load cylinder and reciprocally movable and provided in parallel with the spindle; a joint connecting the load rod and the nut screwed to the spindle; And a hydraulic circuit for controlling the pressure in the load cylinder, which is generated via the load rod by the reciprocating motion, by a relief valve to maintain and operate at a predetermined load over the entire stroke.

(Operation) According to the configuration, the durability tester of the present invention mounts the spindle on the support device. The spindle is rotated by the driving device connected thereto, and reciprocates a nut screwed thereto. The nut is connected to the load rod via a joint, and the reciprocating movement of the nut causes the load rod to reciprocate similarly. The load rod is connected to the load cylinder, and the reciprocating motion generates a pressure in the cylinder. The generated pressure is controlled by a relief valve of the load unit to apply an even load to the load rod, and to apply an even load to the nut connected to the load rod over the entire stroke.

The present invention also provides a plurality of the supporting devices, a spindle is supported on each supporting device, and these are simultaneously rotated by one driving device, and a load of the loading device is applied to each nut of each spindle. By operating, a plurality of spindle-type bolts and nuts are simultaneously subjected to a durability test under the same conditions.

(Embodiment) A spindle-type bolt / nut durability tester according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. FIG.

1 is an explanatory view, FIG. 2 is a sectional view taken along the line II-II of FIG. 1,
FIG. 3 is a sectional view taken along the line III-III of FIG.

This tester is for simultaneously testing the durability of two spindle bolts and nuts. A load is applied to a driving device 1 for rotating a spindle X and a nut Y screwed to the spindle X as shown in FIG. It comprises a load device 2 to act, a detecting device 3 for detecting a load acting on the nut Y, and a support device 4 for mounting the spindle X.

The drive unit 1 is provided with a drive cylinder 6 connected to a rack 5 projecting from the side of the gear box 1a.
Inside, a pinion gear 7 (second illustration) meshing with the rack 5 is provided. A small gear 8 meshing with the pinion gear 7 is provided above the pinion gear 7, and a large gear 9 is provided coaxially with the small gear 8. Also,
A hydraulic unit 14 is provided which communicates with each of the pushing side 6a and the pulling side cylinder chamber 6b of the drive cylinder 6 via the conduits 13a and 13b. The hydraulic unit 14 is provided with a flow regulating valve 15 for driving the drive cylinder 6 at a predetermined speed in the middle of each of the pipelines 13a and 13b.
A directional control valve 16 is provided at the tip of the hydraulic unit side of the conduits 13a, 13b. An oil tank 17 for storing discharged hydraulic oil is provided.

The support device 4 is provided with two gear-shaped drive support portions 10 on both sides of the large gear 9 that mesh with the outer periphery thereof, hold one end of the two spindles X on the inner periphery, and rotate the spindle X.
The support base 12 is provided with two fixed support portions 11 that make a pair with the drive support portion 10 by rotatably holding the other end of the spindle X at a position facing the drive support portion 10.

The load device 2 includes a pair of support portions 10 and 11 of the drive device 1.
And two load rods 18 which are respectively juxtaposed below the spindle X and slidably penetrate the support base 12 and the gear box 1a. A nut Y screwed to the load rod 18 and the spindle X is provided. Are provided.
Two load cylinders 21 each having a piston rod 20 connected to the load rod 18 and reciprocating the load rod 18 are provided at opposing positions on the support base 12 side of the driving device 1. Further, a load unit 23 is provided which communicates with each of the tension side 21a of the load cylinder 21 and each of the extrusion side cylinder chambers 21b via a pair of conduits 22a, 22b. Each pipe line 22a, 22b is provided with a relief valve 24 for controlling the pressure of the cylinder chambers 21a, 21b in the load cylinder 21 generated via the load rod 18 by the reciprocating motion of the joint 19, and the relief valve 24 on the load cylinder 21 side. With pipelines 22a, 22b and oil tank 2
A check is made to prevent the hydraulic oil from being discharged to the oil tank 25 from both sides of the tension side 21a and the extrusion side cylinder chamber 21b of the load cylinder 21 in the middle of the suction line 26. Valves 27a and 27b are provided.

The detecting device 3 is provided with a load cell 28 for both compression and tension for detecting and recording the generated load at the rear end of the load cylinder 21, and a support base 29 against the generated load via the load cell 28.

Next, the operation of the above embodiment will be described with reference to FIG.

Hydraulic oil is pressed into the pushing side 6a of the drive cylinder 6 from the pipeline 13a of the hydraulic unit 1 provided in the drive device 1 and the rack 5 is pushed out in the direction of the arrow. At this time, the pulling side of the drive cylinder 6
The hydraulic oil 6b is discharged to the oil tank 17 through the pipeline 13b while the discharge amount is controlled by the flow control valve 15, and pushes the rack 5 at a predetermined extrusion speed. By pushing the rack 5, the pinion gear 7 is rotated clockwise as viewed from the left end face side of the drive device 1 (the same applies hereinafter). As a result, the small gear 8 and the large gear 9 are rotated counterclockwise in the direction of the arrow, and the two drive supports 10 on both sides of the large gear 9 are simultaneously rotated clockwise in the direction of the arrow. As a result, the spindle X held by the quantity support portions 9 and 10 is rotated clockwise, and the nut Y screwed thereto is connected to the joint Y of the load device 2.
The rotation is suppressed at 19 and the joint 19 is moved together with the joint 19 in the direction of the arrow.

This movement causes the load rod 18 to be connected to the joint 19.
, The piston rod 20 is pulled in the direction of the arrow. At this time, the hydraulic oil on the tension side 21a of the load cylinder 21 is discharged through the pipe 22a, and is prevented from flowing back to the suction pipe 26 by the check valve 27a, and reaches the relief valve 24. The relief valve 24 controls the discharge amount so that the discharge pressure on the pulling side 21b becomes a constant predetermined pressure, and applies a predetermined load to the load rod 18. At this time, when the load rod 18 is pulled,
Pressure is reduced to a suction state, and hydraulic oil is
Check valve 27 by pressure difference between extrusion side 6a and pull side 6b
Instead of a, the air is sucked through the check valve 27b and the pipe 22b.

When the nut Y moves to a predetermined stroke position, limit switches (not shown) provided at both ends of the stroke detect this, and switch the direction switching valve 16 of the hydraulic unit 14,
The hydraulic oil is pressed into the pulling side 6b of the drive cylinder 6 from 13b, and the rack 5 is moved in the direction opposite to the arrow. Thus, the same operation as described above is performed, and the nut Y is moved to the initial position while applying a load. This reciprocating motion is repeated for a predetermined time to perform a durability test of the spindle type bolt / nut.

The set load of the endurance test differs depending on the target spindle type bolt / nut.When replacing the target spindle type bolt / nut, the generated load is individually changed by the compression / tension load cell 28 on the rear end side of the load cylinder 21 via the load cylinder 21. To detect. Each relief valve 24 is throttled or opened according to each detected value, and the relief amount is adjusted so that a fixed set load acts on the nut Y via the load rod 18. As a result, the load generated on the plurality of spindle-type bolts and nuts can be made constant, so that the durability test can be performed under the same conditions.

Here, the load pattern on the nut Y is shown in FIG. 4 and FIG. FIG. 4 is a load-stroke diagram,
The vertical axis is a load, the horizontal axis is a stroke, and a predetermined stroke is moved in one direction while applying an equal compressive load.
The relationship between the load for moving the nut Y in the other direction while applying an equal tensile load and the stroke is shown. In addition, the fifth
The figure is a load-load time diagram, in which the vertical axis represents the load and the horizontal axis represents the load time. The nut Y moves forward while applying a compressive load in the load pattern of FIG. This shows the relationship between the load and the load time when the nut Y is moved backward while applying a tensile load and the movement of these nuts Y is repeated. The load pattern shows the durability test of the spindle type bolt / nut. I do.

(Effects) As is clear from the above description, the present invention provides a load rod maintained at a set load by a relief valve to a nut screwed to a spindle rotated by a driving device, thereby making the nut even. It is possible to provide a spindle-type bolt / nut durability tester that can reciprocate under a proper load state and can easily change the set load only by adjusting the relief amount of the relief valve.

Further, the present invention can provide a spindle-type bolt / nut durability tester capable of improving the test accuracy and shortening the test time by simultaneously performing a durability test on a plurality of the spindles under the same conditions.

[Brief description of the drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is an explanatory view, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a sectional view taken along a line III-III in FIG. FIG. 4 is a load-stroke diagram showing the load pattern of the present embodiment, and FIG. 5 is a load-load time diagram showing the load pattern of the present embodiment. 1 ... Drive device, 2 ... Load device 4 ... Support device 18 ... Load rod, 19 ... Joint 20 ... Piston rod 21 ... Load cylinder, 23 ... Load unit 24 ... Relief valve X ... Spindle type bolt, Y ... Nut

Claims (1)

(57) [Claims] An endurance testing machine for rotating a bolt of a spindle type bolt / nut to reciprocate the nut in a loaded state, comprising a set of support portions for rotatably supporting both ends of a spindle. A plurality of supporting devices are provided side by side, and a driving device that is connected to one end of each spindle supported by each supporting device and rotates them simultaneously, and is screwed to each spindle and moved by the rotation of each spindle. A load device for applying a load in accordance with the movement of each nut, wherein the load device is connected to a load cylinder and a piston rod of the load cylinder, is reciprocally movable, and is provided in parallel with the spindle. A load rod, a joint for connecting the load rod and the nut screwed to the spindle, and the load cylinder generated through the load rod by reciprocating motion of the joint Endurance test machine spindle type bolts and nuts, characterized in that it consists of a hydraulic circuit for acting to maintain a predetermined load over the full stroke control by the relief valve pressure.