JPH11183327A - Test device for ball screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect play and friction of a ball screw easily and surely by a single device by providing a nut holding jig with a holding mechanism which can selectively switch a nut freely between an unrotatable state for detecting play and a rotable state for detecting friction. SOLUTION: A nut holding jig 18 is provided with a holding mechanism 56 for selectively switching a nut 16 freely between an unrotatable state and a rotatable state. In measuring play of a ball screw 12, under the pressure of a clamp member forming the holding mechanism 56, a flange part of a sleeve member is held on a reference surface. Therefore, no load can be applied to a bearing for holding a sleeve member on a jig table 40 in such a manner as to freely rotate, so the play between the nut 16 and a screw bolt 14 can be measured. On the other hand, in detecting friction, guide rods 92a, 92b are fixed through a fixing means 100 to a movable table 94, and the movable table 94 and a load cell 24 are moved forward and backward in a body to detect load. Thus, friction detection work can be conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball screw inspection apparatus for detecting backlash and friction in an axial direction when a screw and a nut constituting a ball screw are screwed together.

[0002]

2. Description of the Related Art In general, ball screws formed by screwing a screw bolt and a nut to each other are used for various purposes. For example, a work transfer device configured by connecting a rotary drive source to one end of a screw bolt and mounting a nut on a work transfer table is widely used.

In this case, since it is necessary to transfer the work to a desired position with high precision and smoothness, an operation for inspecting the axial play between the screw bolt and the nut while the screw bolt and the nut are screwed together is generally performed. ing. For example, Japanese Patent Publication 5-419
As disclosed in Japanese Patent Publication No. 34-34, a nut fixing jig for fixing a nut, a clamp means for non-rotatably clamping one end of a screw bolt screwed with the nut,
Fixing means for fixing the clamp means to a slide table which is movable in the axial direction of the screw bolt so as to swing vertically and horizontally, and mounted on the clamp means;
A load detector that is movable independently of the clamp means by an appropriate distance in the axial direction of the screw bolt, and selectively applies a compressive and tensile load to the screw bolt via the load detector and the clamp means. 2. Description of the Related Art There is known an apparatus including a load applying device to be operated and a displacement meter for measuring the displacement of the screw bolt at the other end of the screw bolt.

[0004]

By the way, ball screws are used to achieve high precision and smooth conveyance of a work.
It is desired to measure whether or not the screw bolt and the nut rotate relatively smoothly in a state in which they are screwed together, that is, to measure friction (friction). However, in the above conventional technology, only the play is detected,
The quality of the ball screw cannot be determined comprehensively, and it is necessary to perform friction measurement in a separate process using a dedicated friction detection device. As a result, it has been pointed out that a dedicated device must be prepared for each of the play measurement and the friction measurement, so that the equipment cost rises and the exclusive space of the equipment is considerably expanded.

SUMMARY OF THE INVENTION The present invention solves this kind of problem, and can easily and reliably detect backlash and friction of a ball screw with a single device, simplifying the entire equipment and reducing the occupied space. It is an object of the present invention to provide a ball screw inspection device capable of effectively performing the above.

[0006]

In order to solve the above problems, a ball screw inspection apparatus according to the present invention first comprises:
The nut is held by the nut holding jig, and one end of a screw bolt screwed to the nut is fixed to the clamp mechanism so as not to rotate. The screw bolt is pressed in the axial direction of the screw bolt via the load detector and the clamp mechanism under the action of the load applying mechanism in a state where the nut is held by the holding mechanism so as not to rotate.
As a result, the non-rotatable screw bolt is displaced in the axial direction with respect to the non-rotatable nut, and the axial play of the ball screw is detected based on the outputs of the load detector and the displacement detection mechanism.

On the other hand, when the screw bolt is pressed in the axial direction while the nut is held rotatably with respect to the nut holding jig, the nut turns with respect to the nut holding jig. Therefore, the friction between the screw bolt and the nut is detected by the load detector via the clamp mechanism, and the friction of the ball screw is detected.

In this manner, the operation of detecting the play of the ball screw and the operation of detecting the friction are performed in a state where the nut is held by the nut holding jig and one end of the screw bolt is fixed to the clamp mechanism so as not to rotate. In addition, a highly accurate detection operation without an installation error or the like can be quickly performed. In addition, the quality of the ball screw can be comprehensively evaluated by one inspection apparatus, so that the equipment cost can be reduced and the space occupied by the equipment can be easily reduced.

Further, the nut holding jig includes a sleeve member rotatable with respect to the base via a bearing,
With the nut fixed to the inner peripheral portion of the sleeve member, the nut rotates integrally with the sleeve member with respect to the base when friction is detected. On the other hand, when play is detected,
The nut fixed to the sleeve member is kept non-rotatable by the clamp member constituting the holding mechanism pressing and holding the sleeve member against the base. This allows
The operation of detecting the backlash of the ball screw and the operation of detecting the friction can be performed with good precision and high accuracy.

Further, the load applying mechanism includes a movable table which can move forward and backward on the slide table via a spring, and fixing means which can fix the movable table to the slide table. When measuring the play of the ball screw,
When the movable table advances and retreats under the action of the rotary drive source, the load detector detects the load on the screw bolt while the impact is absorbed by the spring. On the other hand, when measuring the friction of the ball screw, the movable table is fixed to the load detector via fixing means, and the load detector advances and retreats integrally with the movable table to detect the load on the screw bolt.

[0011]

FIG. 1 is a perspective explanatory view of a ball screw inspection apparatus 10 according to an embodiment of the present invention.
FIG. 2 is an explanatory side view of the inspection device 10. The inspection device 10 detects backlash and friction in the axial direction (the direction of arrow A) of the ball screw 12 in a state where the screw bolt 14 and the nut 16 constituting the ball screw 12 are screwed together.

The inspection apparatus 10 includes a nut holding jig 18 for holding a nut 16, a clamp mechanism 20 for fixing one end 14 a of the screw bolt 14 so as not to rotate, and a clamp mechanism 20 for fixing the screw bolt 14 to the screw bolt 14. A slide table 22 movably supported in the axial direction, a load cell (load detector) 24 mounted on the clamp mechanism 20 and movable by a predetermined distance in the axial direction independently of the clamp mechanism 20; By pressing the screw bolt 14 in the axial direction via the load cell 24 and the clamp mechanism 20, the screw bolt 1
A load applying mechanism 26 for applying a load to the screw 4, and a displacement detecting mechanism 2 disposed on the other end 14 b side of the screw bolt 14 and detecting an axial displacement of the screw bolt 14.
8 is provided.

As shown in FIG. 3, the nut holding jig 18 has a base 32 fixed to a bed 30, and a vertically extending portion of the base 32 is
4 is formed through and a reference surface 3
6 are provided. On the lower side of the base 32, a linear guide 38 is provided extending in the horizontal direction, and a jig base 40 is mounted on the linear guide 38 so as to be able to advance and retreat by a predetermined distance in the direction of arrow A. The sleeve member 4 is attached to the jig base 40 via bearings 42a and 42b arranged in parallel in the direction of arrow A.
4 is rotatably mounted.

At one end of the sleeve member 44, a large-diameter flange portion 46 is provided.
The other end side of the screw part 5 for screwing the set screw 48
0 is provided. A stepped hole 52 is formed at the center of the sleeve member 44 in the direction of arrow A, and the nut 16 is disposed in the stepped hole 52. When the lock member 54 is screwed into the sleeve member 44, the nut 1
6 is fixed to the inner peripheral portion of the sleeve member 44.

The nut holding jig 18 has a holding mechanism 56 which can selectively switch the nut 16 between a non-rotatable state and a rotatable state. As shown in FIGS. 4 and 5, the holding mechanism 56 includes cylinders 58a, 58 arranged vertically.
The rods 60a and 60b protrude from both sides of the cylinders 58a and 58b in different directions.

As shown in FIG. 4, on the rod 60a side,
A first clamp member 62 is provided, and the first clamp member 62 is swingable about a first support shaft 64 as a fulcrum. First
First and second clamp arms 66a and 66b are provided on the distal end side of the clamp member 62 by being divided vertically, and the flange portion 46 of the sleeve member 44 is attached to the ends of the first and second clamp arms 66a and 66b. Pressing bolts 68a and 68b which can be pressed are fixed. As shown in FIG.
On the rod 60b side, a second clamp member 70 is arranged to be swingable about the second support shaft 72 as a fulcrum. At the tip of the second clamp member 70, a pressing bolt 74 that presses the lower end of the jig base 40 against the vertical portion of the base 32 is provided.

The slide table 22 is mounted on a pair of linear guides 76 provided on the bed 30 and is movable in the direction of arrow A. Support blocks 78 and 80 are formed on the slide table 22. The load applying mechanism 26 for urging the slide table 22 is shown in FIGS.
As shown in FIG. 8, a motor (rotational drive source) 84 is fixed to the bed 30 via a mounting base 82, and a screw bolt 90 supported by a bearing 88 is provided on a drive shaft 86 of the motor 84. Be linked. Screw bolt 9
0 is the support blocks 78 and 80 of the slide table 22
And guide rods 92a, 92b are supported by the support blocks 78, 80 so as to be able to advance and retreat with a screw bolt 90 interposed therebetween.

A movable table 94 is provided so as to straddle the screw bolt 90 and the guide rods 92a and 92b. The movable base 94 is provided with a nut member 96 into which the screw bolt 90 is screwed. On both sides of the nut member 96, holes 98a and 98b for inserting the guide rods 92a and 92b are formed. You. Cylinders 102a, 10a constituting the fixing means 100 are provided at both ends of the movable table 94.
2b is fixed. The cylinders 102a, 102 are provided with wedge-shaped locking members 104a, 104b, and the locking members 104a, 104b are used as guide rods 92a, 92b.
Can be inserted into the grooves 106a, 106b formed at predetermined positions (see FIG. 8).

The front and rear ends of the guide rods 92a and 92b are connected to first and second mounting plates 110 and 112, respectively.
And coil springs 114a, 114b and 116a, 116b are interposed between the first and second mounting plates 110, 112 and the movable base 94 by being extrapolated to guide rods 92a, 92b, respectively. . As shown in FIGS. 6 and 7, the first mounting plate 1
10 is provided integrally with a plate portion 118 extending vertically upward, and the load cell 24 is screwed to the plate portion 118. The load cell 24 includes the slide table 22
The load cell 24 is provided movably by a predetermined distance in a direction indicated by an arrow A in the hollow frame portion 120 fixed to the inner surface 122 a of the hollow frame portion 120.
122b, a pair of hemispherical contact terminals 124 that can freely contact
a and 124b are provided. A collet chuck 12 constituting the clamp mechanism 20 is provided at one end of the hollow frame 120.
5 is attached.

As shown in FIGS. 1 to 3, the displacement detecting mechanism 28 has a base 126 fixed on the bed 30, and a cylinder 128 is arranged on the base 126. A rod 130 extending from the cylinder 128 in the direction of arrow A includes
A slide base 132 is fixed, and the slide base 132 is mounted on a rail 134 provided on a base 126.
Guided along. A probe 136 is fixed to the tip of the slide base 132, and the tip of the probe 136 contacts the other end 14 b of the screw bolt 14. Base 1
26, the magnetic scale 13 is parallel to the rail 134.
On the other hand, a linear sensor 140 for detecting the position of the tracing stylus 136 is attached to the slide base 132 via the magnetic scale 138.

The operation of the inspection apparatus 10 configured as described above will be described below.

First, the screw bolt 14 and the nut 16
Are screwed into each other, one end 14a of the screw bolt 14 is inserted into a collet chuck 125 constituting the clamp mechanism 20, and is fixed so as not to rotate. The nut 16 is inserted into the stepped hole portion 52 of the sleeve member 44 constituting the nut holding jig 18, and the lock member 54 is screwed into the sleeve member 44 so that the nut 16 is fixed to the inner peripheral portion of the sleeve member 44. Fixed to The tip of a tracing stylus 136 that constitutes the displacement detection mechanism 28 abuts on the other end 14b of the screw bolt 14.

When the play of the ball screw 12 is detected, as shown in FIG. 4, the cylinder 58a constituting the holding mechanism 56 is driven to move the rod 60a to the arrow A1.
Displace in the direction. When the rod 60a moves in the direction of arrow A1, the first clamp member 62 swings the distal end side in the direction of arrow B with the first support shaft 64 as a fulcrum. For this reason, the pressing bolts 68a, 68b fixed to the first and second clamp arms 66a, 66b
Is pressed against the base 32 toward the reference surface 36, and the sleeve member 44 is held so as not to rotate with respect to the base 32 (see FIG. 9A).

Next, as shown in FIGS. 6 to 8, the motor 84 constituting the load applying mechanism 26 is driven, and the drive shaft 8 is driven.
When the motor 6 rotates in a predetermined direction, the screw bolt 90 connected to the drive shaft 86 rotates integrally. The screw bolt 90 is screwed into a nut member 96 provided on the movable base 94. When the screw bolt 90 rotates, the movable base 94 moves, for example, toward the support block 78 (in the direction of the arrow A1). Moving.

When the movable table 94 moves in the direction of arrow A1,
The coil springs 114a and 114b are compressed, and the first mounting plate 110 is pressed in the direction of arrow A1 by the resilience thereof, and the contact terminals 124a of the load cell 24 mounted on the plate-shaped portion 118 of the first mounting plate 110 Presses the inner surface 122a of the hollow frame 120 in the direction of arrow A1 (see FIG. 7). For this reason, the slide table 22 moves in the direction of the arrow A1 under the guidance of the linear guide 76 integrally with the clamp mechanism 20, and a load in the direction of the arrow A1 acts on the screw bolt 14.

The load acting on the screw bolt 14 in the direction of arrow A1 is detected by the load cell 24, while the amount of displacement of the screw bolt 14 in the direction of arrow A1 is determined by the magnetic scale 13 constituting the displacement detecting mechanism 28.
8 and the linear sensor 140. Therefore, the relationship between the applied load and the displacement of the ball screw 12 in the direction of the arrow A1 is obtained.

Further, when the drive shaft 86 is rotated in the reverse direction under the action of the motor 84 constituting the load applying mechanism 26, the screw bolt 90 connected to the drive shaft 86 is rotated.
The movable table 94 moves in the direction of the arrow A2 via. As a result, the coil springs 116a and 116b are compressed, and the first and second mounting plates 110 and 112
Move in two directions. Plate portion 11 of first mounting plate 110
8 of the load cell 24 attached to the load cell 24
Abuts against the inner surface 122b of the hollow frame 120 and presses it in the direction of arrow A2. For this reason, the slide table 2
2 moves in the direction of the arrow A2, and the screw bolt 14 fixed to the clamp mechanism 20 is pulled in the direction of the arrow A2, and the relationship between the applied load and the displacement in the direction of the arrow A2 is obtained.

Based on the relationship between the applied load and the amount of displacement in the directions of the arrows A1 and A2, the ball screw 12
Is detected, and a play measurement operation is performed to determine the quality of the ball screw 12 (see FIG. 10). A detailed procedure for detecting the amount of backlash displacement is disclosed in Japanese Patent Publication No. 5-41934 by the present applicant.

Next, when performing the friction detecting operation of the ball screw 12, first, as shown in FIG. 5, the cylinder 58b constituting the holding mechanism 56 is driven, and the rod 60b is displaced in the direction of arrow A2. When the rod 60b is displaced in the direction of arrow A2, the second clamp member 70 swings the distal end of the rod 60b in the direction of arrow C with the support shaft 72 as a fulcrum.
Presses the lower side of the jig base 40 in the direction of arrow A1. Thereby, the jig base 40 is pressed and held by the pressing bolt 74 and the vertical portion of the base 32.

At this time, the cylinder 58a is deenergized and the first
Since the pressing force of the rod 60a acting on the clamp member 62 is released, the pressing bolts 68a and 68b are separated from the flange portion 46 of the sleeve member 44. As shown in FIG. 9B, the flange portion 46 separates from the reference surface 36 when the jig table 40 moves a predetermined amount in the direction of the arrow A1. Therefore, the sleeve member 44 is maintained rotatably with respect to the jig base 40 via only the bearings 42a and 42b.

On the other hand, in the slide table 22, the cylinders 102a and 102b constituting the fixing means 100 are driven, and the locking members 104a and 104b are
a, 92b are engaged with the grooves 106a, 106b. For this reason, the guide rods 92a and 92b are integrally held by the movable base 94.

Then, when the motor 84 constituting the load applying mechanism 26 is driven and the screw bolt 90 is rotated in a predetermined direction, the movable base 94 is moved by an arrow via a nut member 96 with which the screw bolt 90 is screwed. It moves in the A1 direction or the arrow A2 direction. Guide rods 92a and 92b are integrally held on the movable base 94 via fixing means 100. When the movable base 94 moves in the direction of arrow A1, for example, the guide rods 92a and 92b are moved.
The first mounting plate 110 moves in the direction of arrow A1 integrally with b. Therefore, the contact terminal 124a of the load cell 24 mounted on the first mounting plate 110 is
And slides the slide table 22 in the direction of the arrow A1 integrally with the hollow frame portion 120.

When the slide table 22 moves in the direction of arrow A1, the screw bolt 14, one end of which is held by the clamp mechanism 20, is urged in the direction of arrow A1, and the screw bolt 14 moves in the direction of arrow A1. The nut 16 screwed to the screw bolt 14 is rotatably maintained with respect to the nut holding jig 18 via the sleeve member 44, and rotates when the screw bolt 14 is urged in the direction of arrow A1, The screw bolt 14 is allowed to move in the direction of arrow A1.

Here, the nut 16 and the screw bolt 1
4 is detected as a load by the load cell 24. Then, as shown in FIG.
The push / pull load Y, which is the applied load, falls within a predetermined threshold range (−y
If a ≦ y ≦ ya), it is determined to be defective.
Thus, the operation of detecting the friction of the ball screw 12 is performed at the same time.

In this case, in the present embodiment, the operation of detecting the backlash of the ball screw 12 and the operation of detecting the friction can be performed by using the single inspection device 10, and the conventional devices which are each performed by a dedicated device. As compared with the equipment, there is an effect that the entire equipment can be simplified and the space occupied by the equipment can be effectively reduced.

In addition, while the nut 16 constituting the ball screw 12 is held by the nut holding jig 18, the one end 14 a of the screw bolt 14 is held by the collet chuck 125 of the clamp mechanism 20 so as not to rotate. A play detecting operation and a friction detecting operation of the ball screw 12 are performed. Therefore, it is possible to avoid a mounting error such as when attaching and detaching the ball screw 12 for each operation, and to perform a highly accurate play detection operation and a friction detection operation, and to easily increase the efficiency of the entire operation. There is an advantage that it can be achieved.

In the present embodiment, when the play of the ball screw 12 is measured, the flange portion 46 of the sleeve member 44 is pressed and held on the reference surface 36 under the pressing action of the first clamp member 62 constituting the holding mechanism 56. I have. For this reason, it is possible to reliably prevent a load from being applied to the bearings 42a and 42b that rotatably hold the sleeve member 44 with respect to the jig base 40, and to prevent play between the nut 16 and the screw bolt 14 with high precision. It becomes possible to measure.

Further, when the movable table 94 is displaced in the direction of arrow A via the load applying mechanism 26 during the play measurement, the coil springs 114a, 114b and 11
The load is applied to the load cell 24 by the resilience of the load cells 6a and 116b, and the impact to the load cell 24 can be effectively absorbed.

On the other hand, at the time of detecting friction, the shock absorbing structure of the load cell 24 by the coil springs 114a, 114b and 116a, 116b is unnecessary. For this reason,
The guide rod 92 is attached to the movable base 94 via the fixing means 100.
The a and 92b are integrally fixed, and the movable table 94 and the load cell 24 are integrally moved forward and backward to detect a load, thereby performing a friction detecting operation. Therefore, the play detecting operation and the friction detecting operation can be performed accurately and efficiently in desired states.

[0040]

As described above, in the ball screw inspecting apparatus according to the present invention, the nut holding jig for holding the nut moves the nut in a non-rotatable state for detecting looseness and in a rotatable state for detecting friction. A holding mechanism that can be switched between is provided.
It is possible to make a general quality judgment of the ball screw with a single inspection device. For this reason, as compared with the case where a dedicated device is provided for the play detection and the friction detection, the size and simplification of the entire equipment can be easily achieved, and the occupied space of the equipment can be greatly reduced. Furthermore, since the backlash detection and the friction detection are continuously performed in a state where the ball screw is once mounted, a highly accurate measurement operation without an installation error or the like is efficiently performed.

[Brief description of the drawings]

FIG. 1 is a schematic perspective explanatory view of a ball screw inspection device according to an embodiment of the present invention.

FIG. 2 is a schematic side view illustrating the inspection apparatus.

FIG. 3 is a partially sectional side view of a nut holding jig constituting the inspection device.

FIG. 4 is a perspective view from one direction of the nut holding jig.

FIG. 5 is a perspective view of the nut holding jig from another direction.

FIG. 6 is a partially cutaway perspective view of a load applying mechanism and a slide table constituting the inspection device.

FIG. 7 is a partial cross-sectional side view of a clamp mechanism, the load applying mechanism, and the slide table that constitute the inspection device.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9A is a diagram illustrating the operation of the nut holding jig when play is detected, and FIG. 9B is a diagram illustrating the operation of the nut holding jig when detecting friction.

FIG. 10 is a diagram illustrating a relationship between a shaft position and a load when a play is measured.

FIG. 11 is a diagram illustrating a relationship between a stroke position and a push / pull load when friction is detected.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Inspection apparatus 12 ... Ball screw 14 ... Screw bolt 16 ... Nut 18 ... Nut holding jig 20 ... Clamp mechanism 22 ... Slide table 24 ... Load cell 26 ... Load loading mechanism 28 ... Displacement detection mechanism 40 ... Jig stand 42a, 42b …
Bearing 44 Sleeve member 46 Flange 56 Holding mechanism 62, 70 Clamping member 84 Motor 90 Screw bolt 92a, 92b Guide rod 94 Movable table 96 Nut member 100 Fixing means 110, 112 Mounting plate

Claims (3)

[Claims] 1. An inspection apparatus for a ball screw for detecting play and friction in an axial direction in a state where a screw bolt and a nut constituting a ball screw are screwed together, wherein a nut holding jig for holding the nut is provided. Tool, a clamp mechanism for fixing one end of the screw bolt in a non-rotatable manner, a slide table for supporting the clamp mechanism movably in the axial direction of the screw bolt, and a clamp mechanism mounted on the clamp mechanism. A load detector that is movable by a predetermined distance in the axial direction independently of the axis, and presses the screw bolt in the axial direction via the load detector and the clamp mechanism, thereby applying a load to the screw bolt. A load applying mechanism to be provided, and the axial displacement of the screw bolt disposed on the other end side of the screw bolt. And a displacement detection mechanism for measuring, wherein the nut holding jig is provided with a holding mechanism capable of selectively switching the nut between a non-rotatable state for play detection and a rotatable state for friction detection. An inspection device for a ball screw. 2. The inspection device according to claim 1, wherein the nut holding jig is rotatably mounted on a base via a bearing, and the nut is fixed to an inner peripheral portion. The ball screw inspection device, further comprising: a clamp member that presses and holds the sleeve member to the base and holds the sleeve member non-rotatably. 3. The inspection apparatus according to claim 1, wherein the load applying mechanism includes a screw bolt connected to a rotary drive source, and a nut to which the screw bolt is screwed, and moves on the slide table. An inspection apparatus for a ball screw, comprising: a movable table capable of applying a load to the load detector via a spring; and fixing means capable of fixing the movable table to the load detector.