JP2009101419A - Servo press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a servo press as the main part materializing a press-fitting or drawing device whose utilizing range is wider than that in the conventional one. <P>SOLUTION: The servo press S is provided with: a servo motor 2 having a driving shaft 5 performing positive or reverse rotation; a deceleration transmitting means for transmitting the positive or reverse rotation of the driving shaft 5 to a ball screw shaft 1; the ball screw shaft 1 positively or reversely rotating in positional fixing; a press rod 4 screwed with the ball screw shaft and progressing or retreating in accordance with the positive or reverse rotation; and a load detecting means for detecting the load applied to the press rod 4. The press rod 4 integrates the rod body 14 performing the press-fitting or drawing of an assembled component and a screwing part 15 screwed with the ball screw shaft 1 in series, and the diameter of the screwing part 15 is almost the same as that of the rod body 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a servo press that can be used as a main part of a press-fitting or drawing device that press-fits an assembly part or the like into an assembly body, or conversely pulls out an assembly part or the like from an assembly body.

Unlike a hydraulic press, a servo press is easy to perform accurate or minute stroke control, and is used as a main part of a press-fitting or drawing device for an assembly part. Traditional servo presses connect a servo motor, which is an electric drive means, and a ball screw shaft that advances and retreats the pressing rod with a toothed belt and a pulley (deceleration transmission means), with a pulley ratio (1/2 to 1/3). The required output torque was ensured while decelerating. However, from the viewpoint of securing a larger reduction ratio, in recent years, servo presses using reduction transmission means using gears have also been seen, and as a press-fitting or drawing device using such servo presses, Patent Literature 1 and Patent Literature 2 etc. can be illustrated.

Patent Document 1 is a technique ( Patent Document 1 Claim 1) that uses a servo press equipped with an AC servomotor (electric drive means) and advancing / retracting (ball screw shaft) as a press-fitting or drawing device. Is provided with a jig detector at the front and rear end of the rotation detector ( Patent Document 2, Claim 2). The rotational drive force of the AC servo motor is transmitted to the advance / retreat via a speed reducer, a belt mechanism (a deceleration transmission means together with the both), and a connecting means such as a gear train ( Patent Document 1, Claim 3). A strain gauge for detecting a load (Claim 4 of Patent Document 1 ) and a sensor for detecting a movement amount of advancing / retreating (the number of rotations of an AC servomotor) are provided on the bag ( Patent Document 1 Claim 5).

Patent Document 2 is a technology that uses a servo press provided with a drive motor (electric drive means), a power transmission mechanism (deceleration transmission means), and a conversion means as a press-fitting or extraction device, and two or more planetary gears as the reduction transmission means. The apparatus (planetary gear mechanism) and the selection means are comprised ( patent document 2 Claim 1 and 5). Examples of the selection means include planetary gears or internal teeth (ring gears) that are slidable in the axial direction ( Patent Documents 2 and 3).

Japanese Unexamined Patent Publication No. 07-164253 JP 2001-347400 A

The pressure input or drawing force required for the press-fitting or drawing device is secured by increasing the torque from the rotational driving force of the electric drive means of the servo press instead of reducing the rotational speed by the speed reduction transmission means. The conventional transmission / reduction transmission means using belts and pulleys has a relatively small reduction ratio, requiring a large motor as an electric drive means, and increasing the servo press size to increase the pulley diameter ratio. . In this respect, the speed reduction transmission means using gears easily achieves a large reduction ratio as compared with the configuration using the belt and pulley, so even if a toothed belt and pulley are used, the pulley ratio is small, that is, the tooth The attached belt and pulley can be reduced in size as a whole. For example, Patent Document 1 uses a gear reduction transmission means, and Patent Document 2 uses a planetary gear mechanism more specifically. In particular, selection of a planetary gear mechanism and setting of a gear are set so that a pressing force (pressure input) can be amplified. ( Patent Document 2 claims 6 to 8). Furthermore, as pointed out in Patent Document 2 , the speed reduction transmission means including the planetary gear mechanism has an advantage that “the inertial force can be reduced to improve the followability to the speed fluctuation”.

  However, installing a planetary gear mechanism in parallel between the servo motor, which is an electric drive means, and the ball screw shaft and the pressing rod increases the size of the servo press. End up. Further, in order to ensure the rigidity of the ball screw shaft in the forward / backward direction of the press rod, a nut that is screwed into the thick ball screw shaft is built in the press rod, so the forward / backward orthogonal direction of the press rod = the width is increased. The problem (actually the problem of increasing the size of the outer cylinder covering the pressing rod) was caused. Such an increase in the size of the servo press has made it difficult to press-fit assembly parts at a narrow pitch in parallel with press-fitting or drawing devices using the servo press, resulting in a problem of limiting the range of use.

  In addition, the press-fitting or drawing device using a servo press is also used for pulling out parts as apparent from the device name. However, in the conventional similar device, a load detection sensor (for example, a strain gauge) is attached to the front end of the pressing rod. Although the load at the time of press-fitting can be detected, the load at the time of pulling out (the load on the pressing rod) could not be detected. In addition to the inability to detect the load at the time of pulling out, when a load detecting sensor is attached to the front end of the pressing rod, the communication line extending from the load detecting sensor becomes an obstacle, and in general, a press-fitting or drawing device using a servo press can be applied. Was causing the problem of limiting.

Therefore, the servo press typified by the use of the press-fitting or extracting device, a focus size reduction, for example, while using a planetary gear mechanism as a speed reducing transmission means, the electric driving means and a ball screw shaft the planetary gear mechanism compactly (1) The outer diameter (outer diameter of the outer cylinder) of the forward / backward portion of the pressing rod is reduced, and (2) not only the advancement (press-fit) of the pressing rod but also the backward movement (withdrawal) Developed servo press as the main part to realize press-in / pull-out device with a wider range of use than before so that the communication line does not hinder the use of press-in / pull-out device while enabling detection of load on the pressing rod In order to study.

What has been developed as a result of the study is an electric drive means having a drive shaft that rotates forward or backward, a deceleration transmission means that transmits forward or reverse rotation of the drive shaft to the ball screw shaft, and forward or reverse rotation with fixed position. In a servo press comprising a ball screw shaft, a pressure rod screwed into the ball screw shaft and advanced or retracted according to the forward or reverse rotation, and a load detection means for detecting a load applied to the pressure rod , the pressure rod is assembled. A rod press that press-fits or pulls out a component and a threaded portion that is threadedly engaged with a ball screw shaft are integrated in series, and the threaded portion is a servo press having substantially the same diameter as the rod body .

(1) The pressing rod is formed by integrating a rod body responsible for press-fitting or pulling out an assembly part and a threaded portion that is threadedly engaged with the ball screw shaft in series, and the threaded portion has substantially the same diameter as the rod body. Suppressing the increase in size of the press rod screwed to the ball screw shaft, and achieving a smaller size than before. This miniaturization is achieved by making the nut screwed to the ball screw shaft longer than before to ensure the same load resistance even with a thin ball screw shaft, and in series with the rod body while keeping the nut approximately the same diameter as the rod body. This is because the diameter of the pressing rod can be reduced as a whole. The integration of the threaded portion and the rod body can be exemplified by, for example, screwing of the threaded portion to the rod body (or screwing of the rod body to the threaded portion) or welding.

In the servo press of the present invention, the speed reduction transmission means is a planetary gear mechanism comprising, for example, a sun gear, a planetary gear, a ring gear, and a carrier that supports the planetary gear, and the sun gear is arranged behind the ball screw axis and on the ball screw axis. The ring gear is fixed to the apparatus main body, and the carrier is connected to the ball screw shaft. As a result, the speed reduction transmission means composed of the planetary gear mechanism is gathered behind the ball screw shaft and arranged in series with the ball screw shaft, so that the forward and backward orthogonal direction = width direction protrusion of the pressure rod by the speed reduction transmission means is suppressed, and the output torque is reduced. The small electric drive means (servo motor), that is, the electric drive means can be miniaturized, and the part from the electric drive means to the deceleration transmission means can be miniaturized. Further, the reduction ratio in the planetary gear mechanism used in the present invention has a relationship of ((number of teeth of the ring gear + number of teeth of the sun gear) / number of teeth of the sun gear), and the ring gear is the pressing object that is the object of the present invention. Even if there is a restriction to reduce the forward / backward orthogonal direction of the rod = width, an appropriate reduction ratio can be secured by adjusting the number of teeth of the sun gear.

(1) The servo press and the press-fitting or drawing device can be miniaturized by improving the pressing rod and the speed reduction transmission means . As a result, the range of use of the press-fitting or drawing device is expanded, so that the load can be detected even when the pressing rod is pulled out. (2) The load detecting means is located behind the rear end of the pressing rod and the ball screw shaft and the deceleration transmission means. It was comprised from the strain sensor which receives distortion generation by the displacement member interposed between. Specifically, for example, a ring-shaped displacement member (transducer) is fitted to the ball screw shaft or the output shaft of the deceleration transmission means, and the displacement member is pushed and pulled by the pressing portions provided on the ball screw shaft and the output shaft, respectively. Thus, there is a configuration in which strain is generated in the strain sensor connected to the displacement member.

According to the present invention, for example , a planetary gear mechanism as a speed reduction transmission means is compactly interposed in series between the electric drive means and the ball screw shaft, and (1) the pressing rod portion (outer cylinder) is made thin and (2 ) It is possible to provide a servo press that enables detection of a load on the pressing rod not only when the pressing rod advances (press-fit) but also when the pressing rod moves backward (withdrawal). The servo press has the advantage that the load can be finely adjusted according to the stroke of the pressing rod, compared to the hydraulic press, and it is desired to press-fit or pull out the assembly parts to a finer part by taking advantage of this advantage. It was. The present invention realizes a servo press composed of a simple and slender outer cylinder while meeting such a demand. This servo press can be provided with an attachment structure such as a flange type, a side mount type, etc. by only partially changing the outer cylinder, and has an advantage that a large number can be arranged in a narrow range. Moreover, according to the present invention, the structure of the servo press can be achieved simply and inexpensively, so that a high cost-effectiveness can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. 1 is a cross-sectional view in the Y-axis direction of the servo press S in which the servo motor 2 is arranged in series with the ball screw shaft 1 as viewed from the X-axis direction. FIG. 2 is a cross-sectional view in the X-axis direction of the servo press S as viewed from the Y-axis direction. 3 is a partially enlarged sectional view showing the vicinity of the planetary gear mechanism 3, FIG. 4 is a front view showing the planetary gear mechanism 3, and FIG. 5 shows a press-fitting or drawing device in which a large number of servo presses are arranged in a narrow range. FIG. 6 is a cross-sectional view of the servo press S in which the servo motor 2 is arranged in parallel with the ball screw shaft 1 as viewed from the Y-axis direction, and FIG. 7 is a view of the servo press S as viewed from the Y-axis direction. It is X-axis direction sectional drawing. 1 and 6 show a state in which the pressing rod 4 is retracted, and FIGS. 2 and 7 show a state in which the pressing rod 4 is extended.

  1 to 4, the servo press S of this example has a servo motor (electric drive means) 2 arranged behind the planetary gear mechanism (deceleration transmission means) 3, that is, in series with the ball screw shaft 1. . Therefore, as is apparent from FIGS. 1 and 2, the servo press S of this example does not have a portion that protrudes greatly in the radial direction of the ball screw shaft 1, that is, in the X and Y directions, and is approximately screwed to the ball screw shaft 1. The outer diameter is equal to the pressing rod 4. As will be described later, since the pressing rod 4 itself has a small diameter, the servo press S of this example is smaller than the conventional servo press of the same type, and the maximum width A is reduced. As a result, the arrangement pitch P is also reduced. . Accordingly, for example, even if the flange 23 is provided on the outer cylinder 21, it is easy to configure the press-fitting or drawing device M in which a large number of servo presses S are arranged in a narrow range (see FIG. 5), and it is narrow for a downsized vehicle engine. There is an advantage that a press-fitting or pulling-out device M that can press-fit all the valve guides or valve seats at a time to the cylinder heads arranged at intervals is obtained. This brings about the effect of the improvement of the working efficiency which finishes assembly | attachment of an assembly part in a short time.

  For example, as shown in FIGS. 6 and 7, even if the servo motor 2 is arranged on the side of the planetary gear mechanism 3, that is, in parallel with the ball screw shaft 1, the servo press S of the present invention does not provide the planetary gear mechanism 3. Since the ball screw shaft 1 is housed behind, the protrusion of the servo motor 2 can be minimized. When arranging a plurality of servo presses S, if they are arranged in the X direction in which the servo motor 2 does not protrude, the servo presses S (FIGS. 1 and 2) are substantially the same as the above-described example. The rotational driving force is transmitted by connecting a driving pulley 6 provided on the driving shaft 5 of the servo motor 2 and a driven pulley 8 connected to a sun gear 10 of a planetary gear mechanism 3 described later by a belt 9.

  As shown in FIG. 3, the planetary gear mechanism 3 includes a sun gear 10, a planetary gear 11, a ring gear 12, and a carrier 7 that supports the planetary gear 11, and the sun gear 10 is behind the ball screw shaft 1 and the ball screw shaft 1. The ring gear 12 is fixed on the line and connected to the drive shaft 5, the position of the ring gear 12 is fixed to the apparatus main body 13, and the carrier 7 is directly connected to the ball screw shaft 1. Thereby, the rotational driving force of the servo motor 2 is decelerated at a reduction ratio of the ring gear 12 ((number of teeth of the ring gear + number of teeth of the sun gear) / number of teeth of the sun gear) and transmitted to the carrier 7. .

  The pressing rod 4 is composed of a rod body 14 and a threaded portion 15, and the threaded portion 15 is threadedly engaged with the ball screw shaft 1 connected to the carrier 7, so that the forward or backward movement is performed according to the normal or reverse rotation of the ball screw shaft 1. To do. In this example, the threaded portion 15 made of a long nut having the same diameter as the rod body 14 is integrated with the rod body 14 by welding or screwing in series, thereby increasing the size of the pressing rod 4 portion. That is, the outer cylinder 21 is prevented from being increased in diameter, and can be easily reduced in size as a press-fit or pull-out device. The advantage that the drawing device M can be configured is obtained.

  The ball screw shaft 1 is connected to an output shaft 16 protruding from the carrier 7. In the present invention, a load detection sensor comprising a displacement member 17 and a strain gauge 22 interposed between the ball screw shaft 1 and the planetary gear mechanism 3 behind the rear end of the pressure rod 4 is configured, and a load applied to the pressure rod 4 is determined. To detect. In this example, a rear pressing portion 18 is provided on the output shaft 16, a front pressing portion 19 is provided on the ball screw shaft 1, and an annular displacement member 17 fixed to the apparatus main body 13 is connected to the front and rear pressing portions 18, 20 via thrust bearings 20, 20. It is pinched at 19. At the time of press-fitting, the rear pressing portion 18 presses the displacement member 17, and the displacement member 17 presses the strain gauge 22 to cause distortion, and detects the pressing load. At the time of pulling, the front pressing portion 19 presses the displacement member 17, and the displacement member 17 pulls the strain gauge 22 to cause distortion, and detects the pulling load. Further, since the load detection sensor can be arranged regardless of the advancement and retreat of the pressing rod as in this example, the signal line (not shown) extending from the strain sensor 22 does not move and does not interfere with the apparatus body 13, for example. Can be. As described above, the servo press according to the present invention has an advantage that the load can be detected not only at the time of press-fitting but also at the time of pulling out the assembled part, and can be processed so as not to obstruct the signal line.

It is the Y-axis direction sectional view which looked at the servo press which arranged the servo motor in series with the ball screw axis from the X-axis direction. It is the X-axis direction sectional view seen from the Y-axis direction of the servo press. It is a partial expanded sectional view showing the planetary gear mechanism vicinity. It is a front view showing a planetary gear mechanism. It is a top view showing the press-fitting or drawing-out apparatus which arranged many servo presses in the narrow range. It is the Y-axis direction sectional view which looked at the servo press which has arranged the servo motor in parallel with the ball screw axis from the X-axis direction. It is the X-axis direction sectional view seen from the Y-axis direction of the servo press.

Explanation of symbols

1 Ball screw shaft 2 Servo motor (electric drive means)
3 Planetary gear mechanism (deceleration transmission means)
4 Pressing rod
10 Sun gear
11 Planetary gear
12 Ring gear
13 Main unit
14 Rod body
15 Threaded part
17 Displacement member
18 Rear pressing part
19 Front pressing part
20 Thrust bearing
21 outer cylinder
22 Strain gauge S Servo press M Press-fitting or drawing device A Servo press (outer cylinder) width P Servo press arrangement pitch

Claims (2)

Electric drive means having a drive shaft that rotates forward or backward, decelerating transmission means that transmits forward or reverse rotation of the drive shaft to a ball screw shaft, a ball screw shaft that rotates forward or backward with a fixed position, and the ball screw shaft In a servo press comprising a pressing rod that is screwed and moved forward or backward according to the forward or reverse rotation, and a load detection means that detects a load applied to the pressing rod,
The pressing rod has a rod main body that press-fits or pulls out the assembly part and a threaded portion that is threadedly engaged with the ball screw shaft in series, and the threaded portion has substantially the same diameter as the rod main body. press. Electric drive means having a drive shaft that rotates forward or backward, decelerating transmission means that transmits forward or reverse rotation of the drive shaft to a ball screw shaft, a ball screw shaft that rotates forward or backward with a fixed position, and the ball screw shaft In a servo press comprising a pressing rod that is screwed and moved forward or backward according to the forward or reverse rotation, and a load detection means that detects a load applied to the pressing rod,
The load detecting means comprises a strain sensor which receives a strain from a displacement member interposed between the ball screw shaft and the deceleration transmission means behind the rear end of the pressing rod .

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