KR20040087962A - A structure for removing backlash of gears and an actuator having the same - Google Patents

Abstract

PURPOSE: A backlash removal structure of a gear and an actuator are provided to engage the driving gear with the driven gear securely by removing backlash between the driving gear and the driven gear with simple structure, and to detect the actual operation angle of the output shaft accurately. CONSTITUTION: A driving gear(33) is fixed to an output shaft(7), and a rotating plate(35) is installed on a chassis(15) and rotated around a supporting shaft(37). A rotating potentiometer(30) is fastened to the rotating plate to detect the rotational angle of the output shaft. A driven gear(34) is fixed to an output shaft of the potentiometer, and engaged with the driving gear without backlash by turning the rotating plate to the output shaft. The rotating plate is fastened to the chassis by two fixing screws(38A,38B) in removing backlash between the driving gear and the driven gear.

Description

{A STRUCTURE FOR REMOVING BACKLASH OF GEARS AND AN ACTUATOR HAVING THE SAME}

The present invention relates to a backlash elimination structure and an actuator of a gear.

In the electric actuator which adjusts the opening degree of valves, such as a butterfly valve and a ball valve, the actual rotational motion angle of the output shaft is detected by an operation position detection means, and a detection signal is fed back to a control part. As a motion position detecting means, a rotational potentiometer is usually used, and the rotation of the actuator output shaft is transmitted to the rotation shaft through a gear train. In this case, when the gears are engaged with each other, backlash is generated, which causes noise and vibration, and greatly affects the detection accuracy. Therefore, when it is necessary to prevent the occurrence of noise and vibration or to detect a precise angle, Japanese Patent Laid-Open Nos. 94-82668 (prior document 1), Japanese Patent No. 94-226803 (prior document 2) and Japan As shown in Unexamined-Japanese-Patent No. 99-082698 (prior document 3), the mechanism which removes the backlash of a gear is added.

Prior art 1 relates to a lens driving device and a lens moving device of a camera. In Priority Document 1, cogwheels respectively provided on the output side of a motor and a potentiometer serving as a driving source, and a floating gear gear meshed with these cogwheels are installed in the unit pedestal. The backlash generated between the gears is automatically removed by applying a force with a spring mechanism to the unit pedestal provided to be rotatable on the drive unit body.

Prior art 2 mentioned above relates to the positioning apparatus of a molding machine. In Prior Art 2, a rack and a rack support member are installed in the driving means. One end of the pinion, which engages the rack and is connected to the rotatable potentiometer, is rotatably mounted to the stationary member via a pivotally oscillating member. The other end of the rocking member is applied by the spring toward the fixing member so that the pinion presses on the rack and at the same time a component force in the rack is generated.

Prior art 3 mentioned above relates to the backlash removal structure of a gear. In prior art document 3, the driving gear and the driven gear are backlashed based on the fitting hole of the fixed shaft which receives the driving gear installed in the cylinder block, and the positioning hole of the rotating shaft where the driven gear is fixed to the cylinder block. It is installed with the distance between the shaft centers to maintain the proper engagement relationship to remove it. A through hole having a positioning portion is provided at the shaft center of the rotating shaft, and a positioning shaft having a jig fitted into the positioning portion and the positioning hole is inserted through the through hole. In the state where the jig is inserted into the positioning portion and the positioning hole, the casing of the rotating shaft and the driven gear is combined with the cylinder block.

However, in the conventional mechanisms for removing the backlash disclosed in Prior Documents 1 and 2, both of the gears are engaged with the springs by applying a force to the swingable member to remove the backlash. As a result, the number of parts increased by the amount of springs, which resulted in complicated structure and increased cost. In addition, there was a problem that the assembly work of the spring is cumbersome.

In addition, the backlash elimination structure of the cogwheel disclosed in the prior document 3 has a problem that the manufacturing cost increases because the fitting holes, the positioning holes, the shafts and the jig that are inserted into these holes must be manufactured with high precision.

As another method of removing backlash, it is possible to increase the precision of the cogwheel, or to use a no-backlash cogwheel to increase the thickness of the cogwheel to eliminate backlash. In this case, however, the cost of the cog wheels is not preferable because of the special order.

SUMMARY OF THE INVENTION An object of the present invention is to provide a backlash removing structure and an actuator for a gear having a simple structure to remove backlash between gears and to secure an appropriate engagement relationship.

1 is a front view of a valve having an actuator according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the inside by removing the cover of the actuator shown in FIG. 1. FIG.

3 is a cross-sectional view of the actuator shown in FIG. 2.

4 is a plan view showing the installation structure of the operation position detecting means shown in FIG.

Fig. 5 is a front view showing the installation structure of the operation position detecting means shown in Fig. 3.

6A to 6C are diagrams for explaining a state in which gears are engaged.

It is a figure which shows the preferable range of the rotation support point of the rotary motion plate shown to FIGS. 6A-6C.

It is a figure which shows the offset of the rotation center, the rotation angle of a rotation plate, and the shift amount of a potentiometer (following gear).

In order to achieve the above object, the backlash elimination structure of the gear wheel according to the present invention, the drive gear wheel provided on the output shaft, the potentiometer for detecting the rotational movement angle of the output shaft, and the driven tooth provided on the rotation shaft of the pot A wheel, and the potentiometer is installed, and a rotary movement plate which gradually engages the driven gear with the driving gear by a rotational movement to remove backlash between the two gears, and the driven gear and the driving gear It is provided with a fixing means for fixing the rotation plate in the rotation position of the backlash is removed.

According to such a configuration, a means for applying a force such as a spring is not required, and high machining precision is not required for each part, so that the backlash of the gear can be removed at low cost, and an appropriate interlocking relationship can be obtained, and assembly is also possible. It is easy to work.

When gears are engaged with each other, when linearly moving a plate provided with driven gears is engaged with each other, when the distal faces of the teeth touch each other, the gears are rotated slightly without engaging the gears. Need to interlock. On the other hand, in the case of using the rotary motion plate, when the plate rotates, the driven gear also rotates with it. Therefore, when the tip surfaces of the driven gear and the cogwheel of the driving gear contact each other and do not mesh properly, the two teeth Slip occurs between the wheels. Therefore, it is possible to reliably engage the plate as compared with the case where the gears are engaged with each other by linearly moving the plate.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 3 illustrate an example in which the backlash elimination structure of the gear wheel according to an embodiment of the present invention is applied to an actuator used for an electric drive valve that controls a flow rate of a fluid flowing through a pipe of an air conditioning facility in a building. .

As shown in FIG. 1, the linear motion drive valve 1 is assembled with the valve main body 2 which forms the flow path of a fluid, and is assembled so that it can move up and down inside the valve main body 2, and the upper end protrudes outward. (3) and a valve plug (4) provided at one end of the valve shaft (3) to open and control the flow path in the valve body (2). The other end of the valve shaft 3 is connected to the output shaft 7 of the actuator 6 via the crank mechanism 5. The opening degree of the drive valve 1 is -80 degrees (variable) of total closing angle, 80 degrees (variable) of an opening angle, and the whole operation angle is 160 degrees (fixed). The angle range that is adjustable by the actuator 6 of the total closing angle and the developing angle is ± 5 °, and is adjusted in units of 1 °. For example, if the total closing angle is set to -83 degrees, the deployment angle is set to 77 degrees in conjunction. The crank mechanism 5 is composed of first and second links 5A and 5B, which converts the rotation of the output shaft 7 into a linear reciprocating motion and transmits it to the valve shaft 3.

In the linear motion drive valve 1 in which the valve shaft 3 is linearly reciprocated as a drive valve controlled by the actuator 6 shown in the present embodiment, it is not possible to directly display the fully closed and unfolded state at an angle. However, the lift amount of the valve shaft 3 is the rotation angle θ of the output shaft 7 (first link 5A), the distance R between the rotational movement points P ₁ , P ₂ of the first link 5A and 2 because they are determined by the distance L between the turning point (P _2, P ₃₎ of the link (5B), this case represents a real operating angle of the output shaft 7 as a full closing angle, the deployment angle of the driven valve 1 . On the other hand, when applied to rotary drive valves such as ball valves and butterfly valves, the crank mechanism 5 is not required, so the coupling between the valve shaft 3 and the output shaft 7 is performed using a coupling. You can connect directly.

As shown in FIGS. 2 and 3, the actuator 6 includes a cover 9 provided with a bracket 10 (FIG. 1) interposed on a frame 8 (FIG. 1) provided on an upper portion of the drive valve 1. ), A cover (not shown) covering the opening of the cover 9, a drive motor 11 provided in the cover 9, an output shaft 7 which is rotated forward and backward by the drive motor 11, An operating range setting mechanism 12 for varying the operating range of the output shaft 7 within a range of ± 5%, a terminal support 13, a circuit board assembly 14, a chassis (fixing member) 15, And an operation position detecting means 16 for detecting the actual operating position (angle) of the output shaft 7. One end 7A of the output shaft 7 protrudes out of the cover 9, and one end of the first link 5A (Fig. 1) is fixed. As shown in FIG. 3, a part of various components of the operating range setting mechanism 12 is provided at the other end 7B of the output shaft 7.

The operating range setting mechanism 12 includes a cam holder 20 and a cam holder 20 in which a lower end body is fitted to the other end 7B of the output shaft 7 and fixed by a fixing screw 21. A cam 24 and a scale plate 25 detachably and rotatably installed by a snap fit mechanism 22 and a tilt mechanism 23, and a cam 24 on the circuit board assembly 14. A pair of limit switches (enclosed switch, deployment switch) 26, 27 fixed to face each other through The fully closed switch 26 is turned on by placing the roller 28 on the large diameter portion 24A of the cam 24 when the valve 1 is in the fully closed state. The deployment switch 27 is turned on by placing the roller 29 on the large diameter portion 24A of the cam 24 similarly when the valve 1 is in the deployed state.

The rotation potentiometer 30 is used as the operation position detection means 16, and as shown in FIG. 5, the rotation of the output shaft 7 is transmitted to the rotation shaft 31 by the gear train 32. As shown in FIG. . The gear train 32 is composed of a drive gear 33 provided on the output shaft 7 and a driven gear 34 provided on the rotation shaft 31. As shown in FIG. 3, the drive gear 33 consists of the large diameter gear part 33A and the small diameter gear part 33B. The large diameter gear part 33A meshes with the drive gear provided in the drive shaft of the drive motor 11, and the small diameter gear part 33A engages with the driven gear 34. As shown in FIG. The potentiometer 30 configured as described above is fixed to the rotational movement plate 35 installed in proximity to the output shaft 7.

As shown in FIG. 4, the rotary motion plate 35 is rotatably supported in the direction in which the rotary motion plate 35 comes close to and separated from the drive gear 33 by the support shaft 37 protruding from the chassis 15. After the backlash of the gear train 32 is removed, the rotary motion plate 35 is fixed to the chassis 15 by two fixing screws 38A and 38B. For this reason, two long holes 39A and 39B through which the fixing screws 38A and 38B are inserted are formed in the rotational movement plate 35 on both sides of the support shaft 37.

The driving gear 33 (small-diameter gear portion (33B)), the module m = 0.5, number of teeth Z ₁ = 57, the standard horizontal (平) gear (spur gear) is used. The driven gear 34 uses a standard spur gear with module m = 0.5 and number of teeth Z ₂ = 22.

As shown in FIG. 6A, when the driving gear 33 and the driven gear 34 are separated from each other, the rotational movement plate 35 is counterclockwise on the left side of the figure (around the support shaft 37). 4 ° in the direction of the direction. In this state, the distance A ₁ between the centers of the two cog wheels 33 and 34 is 21.2 mm.

As shown in FIG. 6B, when the driving gear 33 and the driven gear 34 start to engage, the rotary motion plate 35 is in an inclined state. In this state, the distance A ₂ between the shaft centers of the two gears 33 and 34 is shortened from 21.2 mm to 20.25 mm.

Further, the rotational movement center O ₁ (support shaft 37) of the rotational movement plate 35 in this state is the Y coordinate axis from the center O of the potentiometer 30 (driven gear 34). Distance b (= 13.5 mm) in the direction (orthogonal to the center connection line 40 of the two gears 33 and 34), and distance a (= in the X coordinate axis direction (the direction parallel to the center connection line 40)). 2.25mm).

As shown in Fig. 6C, when the driving gear 33 and the driven gear 34 are properly engaged, the pitch circles of the two gears 33 and 34 coincide, and the backlash is removed. do. In this state, the rotary motion plate 35 is inclined by about 3 ° to the right (clockwise around the support shaft 37) in the figure. The distance A between the shaft centers of the two gears 33 and 34 is 19.75 mm.

The preferable range in which the rotational movement center O ₁ of the rotational movement plate 35 is provided is in the range I indicated by the solid diagonal line in FIG. 7 for reasons of assembly or adjustment. That is, this range I includes the region A in the contour of the potentiometer 30, the region B in the drive gear 33 (small diameter gear portion 33B), and the center connecting line 40. The white and elongated triangular area C of the driven gear 34 on the side opposite to the drive gear 33 and the movable parts D and E of the fixing screws 38A and 38B, in the vicinity thereof and including the driven gear 34. Subtracted from the outer periphery.

In the installation of the potentiometer 30, the two fixing screws 38A and 38B are loosened in advance so that the rotational movement plate 35 can be rotated with respect to the chassis 15, and in this state Fix the installation 30 to the rotary motion plate (35). At this time, as shown in FIG. 6A, the maximum angle (about 4 °) is rotated in the direction away from the output shaft 7 so that the driven gear 34 is not engaged with the driving gear 33. Keep exercise.

The rotary motion plate 35 is then rotated clockwise to the required angle to engage the driven gear 34 with the drive gear 33. When the rotary plate 35 is rotated clockwise by about 4 °, the driven gear 34 starts to engage the drive gear 33 (FIG. 6B). When the rotary motion plate 35 is further rotated by a small angle (about 3 °), the pitch circle of the drive gear 33 and the driven gear 34 coincides completely and the backlash between the two gears is removed. (FIG. 6C). In this state, the fixing screws 38A and 38B are tightened firmly to fix the rotational movement plate 35 to the chassis 15, thereby completing the assembly of the potentiometer 30 to the actuator 6.

Next, the installation condition at the time of setting the potentiometer 30 with respect to the output shaft 7 is examined.

In FIG. 8, the rotational movement center O ₁ of the rotational movement plate 35 is orthogonal to the Y coordinate axis direction (center connection line 40) from the center O of the potentiometer 30 (the driven gear 34). Direction) and the distances offset in the X coordinate axis direction, respectively, a, b, a vertical line passing through the center of rotational movement O ₁ of the rotational movement plate 35, and the center of the potentiometer 30 immediately before engagement ( The angle formed by the line connecting O) and the rotational movement center O ₁ of the rotational movement plate 35 is θ ₁ , and the center O of the potentiometer 30 immediately before the rotational movement of the rotational movement plate 35 is rotated. rotating center (O _1), the connecting line, the center (O) and the rotation angle of the line connecting the rotation center (O ₁₎ that make the movement plate 35 of the potentiometer 30 after engaged with θ, rotational motion If the horizontal movement amount of the potentiometer 30 center O when the plate 35 is rotated and the gears 33 and 34 are engaged with each other is Δx, The relationship of the following formulas (1) to (4) holds.

… … … … (One) … … … … (One')

… … … … (2) … … … … (2')

… … … … (3) … … … … (3 ')

… … … … (4)

If the relationship between (DELTA) x and (theta) is calculated | required from said Formula (1)-(4), it becomes following Formula (5).

… … … … (5)

Therefore, a condition in which Δx> 0 (a condition in which the distance A between the centers of the cog wheels 33 and 34 becomes closer when the potentiometer assembly is moved by θ) is obtained. (I) is obtained.

Here, the conditional expression for satisfying Equation (5) can be represented by the following inequality (6), and the values of a, b, and θ are determined to satisfy this inequality.

… … … … (6)

In the actuator 6 provided with the backlash removal structure of the cogwheel which consists of such a structure, the backlash between the drive cogwheel 33 and the driven cogwheel 34 can be removed, and the two cogwheels can be meshed suitably. . For this reason, the real operation angle of the output shaft 7 can be detected with high precision, and the detection precision by the operation position detection means 16 can be improved.

Further, the rotary motion plate 35 is rotated to engage the driven gear 34 with the drive gear 33 so that the pitch circles coincide with each other, and in this state, the rotary motion plate 35 is fixed with screws 38A and 38B. It only needs to be fixed to the chassis 15 with. For this reason, a means for applying a force such as a spring is not necessary, and the number of parts and the number of steps for assembling the spring can be reduced by a simple structure.

Furthermore, when the driven gear 34 is engaged with the drive gear 33 by the rotational movement of the rotary motion plate 35, even when the front end faces of the teeth of the two cogwheels are not in contact with each other and are engaged with each other, The rotation of the driven gear 33 causes a slip between the two gears. For this reason, the driven gear 34 can be automatically engaged with the drive gear 33, and it is advantageous compared with the case where it engages by linear movement. That is, in the case of meshing by linear movement, even if the tip faces of the teeth of the two gears contact each other, no slippage is caused between the two gears, so that the operator must rotate the gear by hand to engage the gear. do.

On the other hand, in the above-described embodiment, the actuator 6 is applied to the electric drive valve of the air conditioning equipment, but is not limited thereto. For example, the actuator 6 may be used for a damper for opening and closing the exhaust port of the combustion device or the duct. have.

As described above, the backlash removal structure and the actuator of the gearwheel according to the present invention can simply remove the backlash between the gears with a simple structure to secure an appropriate engagement relationship. In addition, the actual operating angle of the output shaft can be detected with high accuracy. In addition, since there is no need to use a spring or the like, the number of parts can be reduced, and it can be provided at low cost.

Claims (8)

A drive gear 33 provided on the output shaft 7, A potentiometer 30 for detecting an angle of rotation of the output shaft, A driven gear 34 provided on the rotation shaft 31 of the potentiometer, The potentiometer is installed, the rotary movement plate 35 to gradually engage the driven gear to the drive gear by the rotary motion to remove the backlash between the two gears, Backlash removal structure of the gearwheel provided with a fixing means (38A, 38B) for fixing the rotational movement plate in the rotational movement position from which the backlash of the driven gear and the driving gear. The method of claim 1, The backlash removal structure of the gear wheel further comprises a fixing member (15) for fixing the rotation plate by the fixing means. The method of claim 2, Further provided with at least one long hole (39A, 39B) formed in the rotation plate, And the fixing member is inserted into the long hole to remove the backlash of the cogwheel including at least one screw that fixes the rotating plate to the fixing member at the rotating position. The method of claim 1, The distance of the center of the said rotary motion plate with respect to the center of the said driven gear in the Y-axis coordinate direction and the X-axis coordinate direction is a and b, respectively, and the center of the said driven gear just before the engagement of two gear wheels. Θ is an angle formed by a line connecting the center of rotational movement of the rotational movement plate and the line connecting the center of the driven gear and the center of rotational movement of the rotational movement plate after two gears are engaged. The backlash elimination structure of a cog wheel, characterized in that the values of a, b, and θ are determined based on. Drive motor 11, An output shaft 7 which rotates forward and reverse by the drive motor, An operation range setting mechanism 12 which variably sets the operation range of the output shaft in a unit range, An actuator having an operation position detecting means 16 for detecting an operating angle of the output shaft, The operation position detecting means A rotation shaft 31 through which the rotation of the output shaft is transmitted; A potentiometer 30 for detecting an operating angle of the rotating shaft; A drive gear 33 provided on the output shaft; A driven gear 34 provided on the rotary shaft; The potentiometer is installed, the rotary movement plate 35 to gradually engage the driven gear with the drive gear by the rotational movement to remove the backlash between the two gears, And a fixing means (38A, 38B) for fixing the rotating plate at the rotational movement position from which the backlash of the driven gear and the driving gear is removed. The method of claim 5, wherein Actuator further comprises a fixing member (15) for fixing the rotational movement plate by the fixing means. The method of claim 6, Further provided with at least one long hole (39A, 39B) formed in the rotation plate, And the fixing member includes at least one screw inserted into the long hole to fix the rotation plate to the fixing member at the rotational position. The method of claim 6, The distance of the center of the said rotary motion plate with respect to the center of the said driven gear in the Y-axis coordinate direction and the X-axis coordinate direction is a and b, respectively, and the center of the said driven gear just before the engagement of two gear wheels. Θ is an angle formed by a line connecting the center of rotational movement of the rotational movement plate and the line connecting the center of the driven gear and the center of rotational movement of the rotational movement plate after two gears are engaged. Actuator characterized in that the value of a, b, Φ is determined based on.