JP2012112395A - Lock holding type linear-guide system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear-guide system having a function holding a lock to a rail at a stop of a block, releasing a lock function at shifting of the same and returning to a lock state when a foreign force in excess of estimation is applied during the shifting.SOLUTION: A clutch mechanism includes a wedge gap provided between the inside of the block 3 and a face of the rail 2 to form a lock means making shifting of the rail 2 in a longitudinal direction impossible. The linear-guide system includes an engagement member as a releasing means for releasing the lock state by removing a roller 12 having the lock function in the direction from a tilting cam face 3n of the clutch at the shifting of the block 3. When the foreign force in excess of the estimation is applied, the roller 12 under removal is returned onto the tilting cam face 3n to return the block 3 to the lock state.

Description

  The present invention relates to an improvement in the function of a linear motion guide device.

  A machine device called a "linear motion guide device" is known as a device that allows a block to move with high precision and small frictional resistance by interposing a rolling element between a block as a moving body and a rail as a fixed body. ing.

  For example, in a machine tool, a linear motion guide device fixes a rail to a machine bed, fixes a stage to a block that moves on the rail, attaches a workpiece to the block, moves the whole, and moves it to a non-moving part. It is often used for a moving stage such as a machine or a measuring instrument that performs a work of cutting or grinding with a fixed blade and a machine or a measuring device that keeps the position after moving to an arbitrary position and works there.

  As a method of moving the block of the linear motion guide device, for example, a nut is attached to the block itself or the stage, a screw shaft connected to a drive device such as a handle or a motor is inserted into the nut, and it is rotated. Since the linear motion guide device using rolling elements has a very small frictional resistance when the block is moved, the drive device can be basically small.

  However, if an unexpected external force is applied to the block while the block or stage is moving or stopped, the small frictional resistance becomes trapped, and most of the external force acts on the drive device side and may damage the drive device itself. is there.

  In particular, when the screw shaft is a ball screw device, a large thrust is simultaneously applied to the screw shaft due to the influence of an unexpected external force, and at the same time a sudden acceleration rotational force is applied.

  In addition, in the drive system using a rack and pinion mechanism or a hydraulic cylinder, the rod or piston shaft is cantilevered due to its structure, so there is a risk of buckling damage due to large thrust acting on the rod or piston due to unexpected external force. .

  In order to prevent damage to the drive unit as a countermeasure against these problems, the design has been forced to eliminate the advantages of the linear motion guide device by increasing the mechanical rigidity of the drive system in advance. Increased physique and cost.

  As another countermeasure, when the brake device is connected to the block and the block stops, a braking force is applied between the rail and the block is locked and held by the friction force, and an external force is applied to the drive device side. Measures are also taken to prevent this, but this also has the disadvantage of not being able to operate the brakes while moving, and at the same time increases the weight, size and cost of new brake devices.

As a conventional technique related to a linear motion guide device, a measuring device including a fixing member and a clamp unit that fixes the positional relationship in the height direction of the stage unit and the measuring unit by sandwiching the fixing member by elastic deformation. Is known (Patent Document 3).
A rotation transmission device in which a two-way clutch is formed using a cam wheel and a rotor is known (Patent Document 1). Further, as a reverse input preventing clutch, a lock means provided between the stationary side member and the output side member for locking the output side member and the stationary side member against a reverse input torque from the output side member, and an input side A lock releasing means provided on the member for releasing the lock state by the lock means with respect to the input torque from the input side member, and provided between the input side member and the output side member, and the lock state by the lock means is released. There is known a reverse input prevention clutch provided with a torque transmission means for transmitting an input torque from an input side member to an output side member when the state is in the state (Patent Document 2).

Patent Publication 2000-346103 Patent Publication 2002-266902 Patent Publication 2005-147808

  The present invention has been made to cope with such a problem. When the block is stopped, the block is locked with respect to the rail, and when the block is moved, the locked state with respect to the direction is released so that the block can move. An object of the present invention is to provide a lock holding type linear motion guide device having a function capable of quickly returning to a locked state when an unexpected external force is applied during movement.

A lock holding type linear motion guide device of the present invention is a linear motion guide device in which a block moves along a rail and the rail, and restrains the movement of the block relative to the rail inside the block. A lock means and a release means for releasing the restraint state by the lock means,
The locking means is a clutch mechanism formed by a wedge portion formed between the rail surface and the block surface at a position facing the rail surface, and a roller disposed in the wedge portion. And

Further, the wedge portion in the locking means is formed between the rail surface by providing a pair of or more inclined cam surfaces in a part of the block surface at a position facing the rail surface, and the inclined cam surface. The direction of the block is narrower in the direction in which the block advances and the direction in which the block advances, the angle with respect to the upper surface of the rail is set to 5 to 15 °, and a roller is placed on each of the pair of wedge portions. Each of which is provided with an elastic member that presses against the wedge part,
The release means is a release member that selectively engages a roller on the opposite side of the block among the rollers and presses the roller in a direction opposite to the direction of the wedge portion. The gap δ _{0 in} the longitudinal direction of the rail in between has a relationship of 0.2 to 0.8 times the gap δ ₁ that can move in the longitudinal direction of the rail in the block of the release member. It is characterized by.

As a means for moving the release member of the release means in the longitudinal direction of the rail,
(1) It has an electric circuit that uses the attractive force of the electromagnet and senses an abnormal value for normal mechanical vibration or power consumption to cut off the energization of the electromagnet;
(2) The ball screw nut is restrained only in the rotational direction in the block and incorporated in a state in which the ball screw nut can move within a limited range in the axial direction; or
(3) The rod inserted into the block is connected to the engaging member with a screw or a pin, and the rod is assembled in a movable state with a gap within a limited range with respect to the block. And

  In the lock holding type linear motion guide device of the present invention, the rail and the block moving along the rail each have a rolling surface on which rolling elements roll, and the rolling space is constituted by the rolling surfaces. The rolling element is provided with a reversing member for returning the rolling element separated from the rolling space to the rolling space again, and the block moving along the rail is a so-called rolling guide. It is characterized in that it is a system or a sliding guide system.

  The lock holding type linear motion guide device of the present invention is provided with a wedge gap facing each other between the rail surface inside the block and pressing the roller against the cam surface constituting the wedge gap with an elastic member to advance and Since a clutch mechanism that cannot be moved backward is provided and used as a lock means, the block cannot be moved in the longitudinal direction of the rail when locked. For this reason, when the block is stopped, the rail is always locked, and when the external force is applied even during movement, the lock quickly returns to the locked state, so an unexpected external force is applied to the drive side. There is no.

  Further, when moving the block, an engaging member for separating the roller from the cam surface is provided inside the block, and the engaging member is moved by applying a force to the engaging member from the outside. Is released from the cam surface to release the lock function, so that the lock can be easily released.

  The lock holding type linear motion guide device of the present invention does not require, for example, increasing the mechanical rigidity in advance or adding a new brake device so that the driving device itself is not damaged by an unexpected external force. The increase in the overall weight, its size and cost can be suppressed. Further, since the rigidity in the longitudinal direction of the block rail is increased, when applied to a machine tool, it can greatly contribute to improvement of machining efficiency and machining accuracy.

It is a typical usage example of a linear motion guide device. It is the top view and sectional drawing of the conventional linear motion guide apparatus. It is sectional drawing of the lock holding | maintenance type linear motion guide apparatus by this invention. It is an external view of the dent part of the block of this invention product. It is an external view of the holder | retainer place and spring of this invention goods. It is explanatory drawing of the lock function cancellation | release of this invention product. It is an assembly drawing of the product of the present invention incorporating a ball screw nut. It is an assembly drawing of the product of the present invention incorporating a rod.

  FIG. 1 shows a typical use example of a linear motion guide device, in which two rails 2 are fixed in parallel to a bed 1 of a machine tool, and an upper part of a block 3 movable on the rails 2. It is a figure showing the state which is cutting with the cutter 7 which fixed the stage 4 and fixed the workpiece 5 to the upper part of the stage 4, and attached it to the rotating spindle 6.

  A nut 8a of a ball screw device 8 (not shown) is fixed to the rear surface of the stage 4, and a ball screw shaft 8b passes through the nut 8a, and the ball screw shaft 8b passes through the nut 8a by an external drive device (not shown). A rotational force is applied to the shaft 8b to move the stage 4 forward or backward in the XX direction of FIG. The shaft end of the ball screw shaft 8 b on the side opposite to the driving side is supported by a bearing housing 9.

  In an actual machine tool, the rotary spindle 6 in FIG. 1 can be moved in the Y-Y direction in addition to the movement in the Z-Z direction, or the stage 4 moving system in FIG. A method of processing the workpiece 5 by fixing the workpiece 5 at right angles so that the workpiece 5 can freely move in both the XX direction and the YY direction is also employed.

  By the way, the mechanical rigidity of the stage 4 fixed to the linear motion guide device is very large in the YY direction and the ZZ direction in FIG. Since it is almost zero, the mechanical rigidity in the XX direction is actually governed by the mechanical rigidity of the ball screw device 8 for driving the stage 4, so that the rigidity is in the YY direction of the linear motion guide device. Compared with the Z-Z direction, it becomes very small.

  The machining capability and machining accuracy of a machine tool improve as the rigidity in all of the XX, YY, and Z-Z3 directions increases. Therefore, the movement rigidity of the block 3 of the linear motion guide device, that is, the machine rigidity in the XX direction is improved. If the height is increased, the ball screw device 8 and the like may be small.

  FIG. 2 shows the basic structure of the linear motion guide device. As shown in FIG. 2 (a), a groove 2a for rolling the steel ball 3a is provided on the width surface of the rail 2, and a groove 3c is provided inside the foot 3b of the block 3 facing the groove 2a. A rolling space 3d of the steel ball 3a is formed between them, and the steel ball 3a is held and inserted into the rolling space 3d by the cage 3e.

  When the block 3 moves with respect to the rail 2, the steel ball 3a moves relative to the block 3 and is released from the rolling space 3d. Therefore, a reversing member 3f is provided to return to the rolling space 3d again. A steel ball 3a is annularly arranged between the circulation groove 3i formed by the respective grooves 3h and 3g provided on the inner side of the reversing member 3f and the outer side of the foot 3b of the block 3, and the rolling space 3d. In this way, the block 3 can move continuously on the rail 2.

  Further, a seal member 3j is attached to the outside of the reversing member 3f in order to keep the inside of the circulation groove 3i and the rolling space 3d and the steel balls 3a and the cage 3e clean.

  Since the block 3 of this linear motion guide device is guided to the rail 2 via a number of steel balls 3a, the rigidity in the YY and ZZ directions in FIG. Becomes almost zero because only the rolling resistance of the steel ball 3a is obtained.

  The object of the present invention is to increase the mechanical rigidity in the XX direction while maintaining the function that the block 3 of the linear motion guide device can move with respect to the rail 2 as in the conventional product.

  FIG. 3 shows the basic structure of the main part excluding the foot 3b of the block 3, the steel ball 3a, the reversing member 3f, and the sealing member 3j as a linear motion guide device in the present invention. The clutch mechanism 10 is incorporated between the inner side of the block 3 that faces the upper surface 2b and the upper surface 2b of the rail 2 as a locking means, and the cage 11 that is a component of the clutch mechanism 10 is moved in the longitudinal direction of the rail 2. By doing so, it is characterized in that it is a means for releasing the lock by moving the roller 12 in the engaged state.

  FIG. 4 shows the external appearance of the inner shape of the block 3 located at the position facing the upper surface 2 b of the rail 2 as viewed from the rear side. The first recess 3 k, the second recess 3 m and the block 3 The first recess 3k has a pair of inclined cam surfaces 3n facing the direction in which the block 3 moves on the rail 2, and the inclined cam surface 3n and the rail A pair of wedge portions are formed between the upper surface 2b of the two.

  The retainer 11 shown in FIG. 5 is inserted into the recesses 3k and 3m. The retainer 11 as a release member has a central column 11a and two pockets 11b, and an engagement member is provided in the pocket 11b. And a spring 13 as a pressing member.

When the retainer 11, the roller 12 and the spring 13 are assembled in the block 3 and are combined with the rail 2, the positional relationship in the neutral state is as shown in FIG. It is pushed into the central part of the slope of the surface 3n. At that time, the roller 12 secures a slight gap δ ₀ between the outer pillar 11 c of the cage 11 in both the XL direction and the XR direction.

  In the longitudinal direction of the rail 2 of the cage 11 as a release member in the locked state, the suction member 11d is fixed to the central column 11a of the cage 11 with a screw 11e, and this is fixed in the through hole 3p of the block 3. This is performed by attracting with the electromagnet 14 made.

The gap between the attracting member 11d fixed to the cage 11 and the attracting surface 14a of the electromagnet 14 is set to δ ₁ in both the X _L direction and the X _R direction. The size of this gap is outside the cage 11. Is set between 125% and 500% of the gap δ ₀ between the column 11c and the roller 12.

When the suction surface 14a of the electromagnet 14 attracts the attracting member 11d, here outside of the column 11c of the retainer 11 in the X _L direction and X _R direction both for preventing the collision the wall 3q block 3 gap δ ₂ is secured, but this gap is set larger than the gap δ ₁ between the attracting member 11d and the attracting surface 14a of the electromagnet 14.

  The retainer 11 is fitted in a direction perpendicular to the rotation axis of the roller 12 and between the upper surface 2 b of the rail 2 and the first recess 3 k of the block 3 with a small gap. Can move smoothly only in the longitudinal direction.

  The gradient θ of the inclined cam surface 3n provided in the first recess 3k of the block 3 with respect to the rail upper surface 2b is produced in the range of 5 ° to 15 ° in order to ensure the locking function as a clutch, and is in a neutral state. Then, in order to reliably push the roller 12 into the inclined cam surface, the spring 13 as a pressing member presses the roller 12 toward the inclined cam surface 3n with an appropriate force. The gradient θ of the inclined cam surface 3n with respect to the upper surface 2b of the rail 2 requires an angle of 5 ° to 15 ° at the contact point with the roller 12, so that the inclined cam surface 3n is a curved surface even if it is flat. May be.

In FIG. 3, each of the two rollers 12 is pressed against the cam surface 3n by the spring 13, so that the block 3 moves in a locked state as a clutch in both the X _L direction and the X _R direction. It becomes impossible and becomes a structure as a lock means.

The function of unlocking the lock holding type linear motion guide device according to the present invention will be described below.
Now, when energized left side of the electromagnet 14 in FIG. 3, is shown in Figure 6 in close contact adsorbing member 11d fixed to the retainer 11 and the suction surface 14a, the gap [delta] ₁ of the original X _L side clearance [delta] ₁ of X _R side is twice the original clearance becomes zero.

In conjunction with this, the roller 12 on the X _R side is pushed by the column 11c outside the cage 11 and moves in the X _L direction, but the neutral gap δ _{0 in} FIG. 3 is set to be smaller than δ _1. Therefore, the roller 12 is disengaged from the engaged state with the inclined cam surface 3n and loses the lock function as a clutch. Therefore, the block 3 can be moved in the _XL direction in FIG. Incidentally, the roller 12 of the X _L side with respect to movement in the X _R direction maintaining the state of holding the lock function for movement in the X _R direction so pressed by the spring 13 maintains the engagement ing.

Moreover, because it is larger than the suction surface 14a and the retainer 11 suction member 11d is a gap [delta] ₂ of the neutral state even closely fixed to the [delta] ₁ of X _L side of the electromagnet 14 in the state of FIG. 6 The column 11 c outside the cage 11 does not interfere closely with the wall 3 q of the block 3.

When the block 3 is moved in the _XR direction in FIG. 6, energization of the electromagnet 14 on the left side of the paper may be interrupted and the electromagnet 14 on the right side of the paper may be energized.

  As described above, when the block 3 is moved, the locked state can be released without requiring a special mechanical operation only by energizing the electromagnet 14 in the direction to be moved.

  When the product of the present invention is actually applied to a machine tool or the like, while the block 3 is moving, there is no locking function in the moving direction, so the mechanical rigidity is zero, but when an unexpected external force is applied, the machine vibration If the energization to the electromagnet 14 is cut off by detecting a sudden change in the load or a sudden change signal of the load power during processing, the retainer 11 as the unlocking means is quickly moved by the force of the spring 13 incorporated in the pocket 11b. Return to the neutral position and return to the locked state.

  As described above, the mechanical rigidity in the XX direction can be increased only by changing the system using the linear motion guide device of FIG. 1 to the lock holding type linear motion guide device of the present invention.

FIG. 7 shows another application example of the present invention, in which the nut 8a of the ball screw device 8 is constrained in the rotation direction in the block 3, and the gap δ is formed in the X _L direction and the X _R direction in the axial direction. ₁ is secured and mounted in a movable state. In this structure, the function of holding and releasing the lock equivalent to the product of the invention of FIG. 3 can be obtained without using the electromagnet 14.

FIG. 8 shows a structure in which a cantilevered rod 15 such as a rack and pinion mechanism or a hydraulic cylinder device is attached to the block 3 of the present invention to obtain a lock holding and releasing function. The rod 15 is provided with a flange 15a. Is secured to the retainer 11 with a pin 16 and a clearance δ ₁ is secured between the cover 17 and the cover 17 in both the X _L direction and the X _R direction to allow the rod 15 to move. When the rod 15 is pushed in the X _L direction, the lock function of the X _R side roller 12 is released and the block 3 can be moved in the X _L direction, so that the function equivalent to the product of the invention of FIG. 3 can be obtained.

  In the structure of FIGS. 7 and 8, the retainer 11 returns to the neutral position relative to the block 3 when the block 3 is suddenly moved in the moving direction by an unexpected external force, so that it is detached from the inclined cam surface 3n. The roller 12 that has been engaged is reengaged to return to the locked state.

  The above description is an invention in which a lock holding and releasing mechanism is added to a linear motion guide device using the rolling element 3a. However, since the essence of the present invention relates to the lock holding and the releasing mechanism, the rolling element 3a is used. The mechanism of the present invention may be applied to a sliding guide type linear motion guide device that does not.

  Further, although the description of the present invention has been described with the linear motion guide device, it can also be applied to a curved guide device in which the rail has an arc shape.

  Since the lock holding type linear motion guide device of the present invention is electrically operated for switching between holding and releasing the lock, it can be easily applied to a machine tool using a plurality of linear motion guide devices. Further, since the lock holding and release operation can be performed purely mechanically, it is economical to apply to a moving stage of a measuring instrument.

DESCRIPTION OF SYMBOLS 1 Bed 2 such as a machine tool Rail 2a of linear motion guide device 2b Groove 2b where the steel ball rolls Upper surface 3 Block 3a of the linear motion guide device Steel ball 3b Foot 3c Groove 3d where the steel ball rolls Rolling space 3e Retainer 3f Reverse Member 3g Steel ball circulation groove 3h Steel ball circulation groove 3i Circulation groove 3j Seal member 3k First recess 3m Second recess 3n Inclined cam surface 3p Through hole 3q Wall 4 Stage 5 Workpiece 6 Spindle 7 Blade 8 Ball screw device 8a Ball screw nut 8b Ball screw shaft 9 Bearing box 10 Clutch device 11 Retainer 11a Central column 11b Pocket 11c Retainer outer column 11d Adsorption member 11e Screw 12 Roller 13 Spring 14 Electromagnet 14a Electromagnet adsorption surface 15 Rod 15a Flange 16 Pin 17 Cover δ ₀ Clearance between the outer column of the cage and the roller δ ₁ Adsorption member and adsorption surface of the electromagnet Gap δ ₂ Gap between cage outer column and block wall θ Gradient of inclined cam surface relative to rail surface X _L Movement leftward on paper X _R Movement rightward on paper

Claims (5)

A linear motion guide device in which a block and a block move along the rail,
Inside the block, there is a lock means for restraining the movement of the block relative to the rail, and a release means for releasing the restrained state by the lock means,
The locking means is a clutch mechanism formed by a wedge portion formed between a surface of the block in a position facing the rail surface and a roller disposed in the wedge portion. A lock holding type linear motion guide device. The wedge portion in the locking means is formed between the rail surface by providing a pair of or more inclined cam surfaces in a part of the block surface at a position facing the rail surface, and the direction of the inclined cam surface Is a shape that narrows in the direction in which the block moves forward and backward, the angle with respect to the upper surface of the rail is set to 5 to 15 °, and a roller is placed on each of the pair of wedge parts, An elastic member that presses against the wedge part;
The release means is a release member that selectively engages a roller on the opposite side of the block among the rollers and presses the roller in a direction opposite to the direction of the wedge portion. The gap δ _{0 in} the longitudinal direction of the rail in between has a relationship of 0.2 to 0.8 times the gap δ ₁ movable in the longitudinal direction of the rail in the block of the release member The lock holding type | mold linear motion guide apparatus of Claim 1 characterized by these. As means for moving the release member of the release means in the longitudinal direction of the rail,
(1) It has an electric circuit that uses the attractive force of the electromagnet and senses an abnormal value for normal mechanical vibration or power consumption to cut off the energization of the electromagnet;
(2) A ball screw nut is constrained in the block only in the direction of rotation, and is incorporated in a state where it can move with a gap within a limited range in the axial direction; or
(3) The rod inserted into the block is connected to the engaging member with a screw or a pin, and the rod is assembled in a movable state with a gap within a limited range with respect to the block. The lock holding type linear motion guide device according to claim 2.   The rail and the block moving along the rail each have a rolling surface on which the rolling element rolls, and the rolling element is disposed in a rolling space constituted by the rolling surfaces, and the rolling space. The lock holding type linear motion guide device according to claim 1, further comprising a reversing member for returning the rolling element separated from the rolling space to the rolling space again.   4. The lock holding type linear motion guide device according to claim 1, wherein the rail and the block moving along the rail are of a sliding guide type.

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