JP2008213070A - Press-in device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide press-in device and method for strictly guaranteeing press-in of a press-in member up to a stipulated position. <P>SOLUTION: In this press-in device, an outer race 30 is held by a press-in head part 50, and a plate 21 is held by a rotary head part 52 located at a distal end of the press-in head part 50. In this state, the outer race 30 is pressed into a case 10 together with the plate 21, and the rotary head part 52 is rotated and driven in a press-in state of the outer race 30. At this time, the plate 21 is not rotated, if the outer race 30 is normally pressed in, while the plate 21 is rotated if the outer race 30 is not normally pressed in. Namely, rotation frictional resistance of the plate 21 and the outer race 30 is utilized, and thereby propriety of the press-in state is determined by depending on whether the plate 21 (rotary head part 52) is rotated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a press-fitting device and a press-fitting method for press-fitting a press-fitting member into a predetermined bottomed hole provided in a workpiece. More specifically, the present invention relates to a press-fitting device and a press-fitting method that guarantee a press-fitted state of a press-fitting member with high accuracy.

  Conventionally, a tapered roller bearing having a tapered roller is incorporated in a drive unit (transaxle) of an automobile. For example, as shown in FIGS. 13 to 14, a transaxle case 10 provided with a mounting opening 11 is prepared, and an outer race 30 is press-fitted together with the plate 20 into the mounting opening 11. The mounting opening 11 is a bottomed hole having a bottom surface 12, and a through portion 13 is provided in a part of the bottom surface 12. In press-fitting, the outer race 30 is pushed in until the bottom surface 12 is reached with the plate 20 in between. Thereafter, the inner race 40 that engages with the rotating body 42 such as a gear is assembled together with the tapered roller bearing 41.

  Further, in the tapered roller bearing 41, an appropriate pressing force is applied between the tapered roller bearing 41 and the outer race 30, and the rotation torque (preload torque) in the initial state is set to a predetermined value. As a method for adjusting the preload torque, for example, a position adjusting plate 20 such as a shim is inserted between the case 10 and the outer race 30.

  Since the tapered roller bearing 41 used for the transaxle is exposed to a high thrust load, it is necessary to set the preload torque strictly. As a typical failure factor of the preload torque, a gap in the press-fitting direction existing between the case 10 and the outer race 30 can be considered, and the preload torque changes when the gap is tightened during driving. As a result, the durability of the tapered roller bearing decreases.

  Therefore, it is necessary to ensure that the outer race 30 and the plate 20 are securely press-fitted. That is, it is necessary that the outer race 30, the plate 20, and the case 10 are in contact with each other without a gap. Thus, as a press-fitting device for confirming the press-fitted state, for example, there is a method of assembling a tapered roller bearing disclosed in Patent Document 1. In the assembling method of this patent document 1, whether the press fit is good or not is judged while comparing the press fit thrust with the stroke. That is, the quality of press-fitting is assured at two points: (1) press-fitting with a sufficient press-fitting thrust, and (2) press-fitting depth being within the standard.

In addition, there is a press-fitting device disclosed in Patent Document 2, for example, for measuring the press-fitting thrust. Moreover, as what measures press-fit depth, there exists a press-fit apparatus currently disclosed by patent document 3, for example.
Japanese Patent Laid-Open No. 2003-194082 JP 2000-94236 A JP-A-6-126551

  However, the conventional press-fitting device described above has the following problems. In other words, in the management based on the press-fitting thrust, the cylinder hydraulic pressure is actually measured with a hydraulic gauge, not the pressure thrust itself. As a result, hydraulic pressure loss occurs due to deterioration of the cylinders and pipes.

  Also, the control by the depth of press-fitting is the measurement of the cylinder length from a predetermined position of the press-fitting device, and cannot cope with the press-fitting variation within the dimensional tolerance of the press-fitting member. On the other hand, even if a minute foreign matter is caught between the outer race 30 and the transaxle case 10 and the minute foreign matter is within the dimensional tolerance, the change in the preload torque is large. Therefore, these methods cannot guarantee the exact press-fitted state.

  The present invention has been made to solve the problems of the conventional press-fitting device. That is, the object is to provide a press-fitting device and a press-fitting method that can strictly guarantee that the press-fitting member is press-fitted to a specified position.

  A press-fitting device made for the purpose of solving this problem is a press-fitting device that press-fits a press-fitted member having a through hole into a predetermined bottomed hole provided in a work with a plate member interposed therebetween. A press-fit shaft that is movable in the press-fit direction, a press-fit head that is positioned at the tip of the press-fit shaft and holds the press-fit member through the through-hole of the press-fit member, and a tip that is located at the tip of the press-fit head The rotary member is detachably fitted to the plate member and is provided to be rotatable about the axial direction of the press-fitting shaft, a drive unit for rotationally driving the rotary unit, and the rotation status of the rotary unit are detected. And a press-fitted state diagnosis unit that determines whether the press-fitted state of the press-fitted member is good or not based on the detection result.

  In the press-fitting device of the present invention, the press-fitting head part holds the press-fitting member through the through-hole of the press-fitting member, and further holds the plate member at the rotating part located at the tip of the press-fitting head part. The rotating portion and the plate portion are detachably fitted. The fitting between the two is performed, for example, by providing a notch portion in the plate portion and a protrusion portion engaging with the notch portion in the rotating portion, and fitting the both. In other words, when the two members are fitted, the plate member is rotationally moved with the rotation of the rotating portion. In this state, the press-fitting shaft is moved to the work side, and the press-fitted member is press-fitted into the bottomed hole of the work together with the plate member (press-fitting step).

  Thereafter, with the press-fitted member being press-fitted, the rotation unit is driven to rotate by the drive unit (rotation step). At this time, if the press-fit member is normally press-fitted into the work, the plate member sandwiched between the press-fit member and the work is prevented from rotating by the frictional resistance between the press-fit member and the work. Therefore, the rotating part is not rotated. On the other hand, if the member to be pressed is not normally pressed into the workpiece, there is a gap between the plate member and the member to be pressed or the workpiece. Therefore, the frictional resistance between the plate member, the press-fitted member, and the work is smaller than the torque of the rotating part, and the plate rotates with the rotation of the rotating part. That is, it is possible to determine whether the press-fitted state is good or not by using whether or not the rotating part or the plate member is rotating by using the rotational frictional resistance.

  Therefore, the press-fit state diagnosis unit detects the rotation state of the rotary unit, and determines whether the press-fit state of the press-fit member is good or not based on the detection result (press-fit state diagnosis step). That is, in the press-fitting device according to the present invention, the press-fitting state can be determined from the actual contact state between the plate member and the press-fitted member and the close contact state between the workpiece and the plate member, and the press-fitting state is estimated from the press-fitting thrust and the press-fitting depth Compared with this technology, the press-fit state is more strictly guaranteed.

  As a method for determining whether the rotating unit is rotating, for example, the driving unit includes an air motor, the rotating unit is driven to rotate by the air motor, the press-fitting state detecting unit detects the back pressure of the air motor, and the back pressure of the air motor is a predetermined value. If it is above, it will be judged that the rotation part is not rotating. That is, if the air motor cannot rotate, the input compressed air is exhausted without being used for the rotation of the air motor. As a result, the back pressure increases. On the other hand, if the air motor can rotate, the input compressed air is used to rotate the air motor, and the back pressure does not increase. Therefore, the quality of the press-fitted state can be determined by detecting the back pressure of the air motor. In addition, if the drive unit includes an electric motor and performs rotation control by a servo mechanism, the rotation state of the electric motor can be detected based on the control signal.

  Further, the plate member of the present invention is used for the inspection of the press-fitted state of the press-fitted member, but it is better to be a shim member that adjusts the position of the press-fitted member in the press-fitting direction. That is, when the press-fitted member is press-fitted into the workpiece, a position adjusting member such as a shim is used to adjust the dimensional error between the two. Therefore, the plate member also serves as a position adjustment function, so that the press-fit state can be assured with high accuracy without increasing the number of parts.

  According to the present invention, a press-fitting device and a press-fitting method capable of strictly guaranteeing that the press-fitting member is press-fitted to a specified position are realized.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a press-fitting device for assembling an outer race of a tapered roller bearing to a predetermined mounting opening of a transaxle case. The outer race and the case as the workpiece are the same as those in the prior art, and will be described using the same symbols as in FIGS.

  As shown in FIG. 1, the press-fitting device 100 of the present embodiment is positioned immediately above the work support base 60 on which the transaxle case 10 serving as a work is placed, and the case 10 placed on the work support base 60. A press-fitting head portion 50 that faces the mounting opening 11 of the case 10 and holds the outer race 30, and a press-fitting cylinder 5 that holds the press-fitting head portion 50 and is slidable in the press-fitting direction (vertical direction in FIG. 1). And a top plate 61 that slidably supports the press-fitting cylinder 5.

  The press-fitting cylinder 5 is a hydraulic cylinder and is provided with a hydraulic gauge 63 for measuring the hydraulic pressure. The oil pressure gauge 63 detects the press-fitting thrust that changes with the press-fitting cylinder portion 5 when it is moved up and down. A position sensor 64 is attached to the top plate 61. The position sensor 64 detects the press-fitting depth that changes with the press-fitting cylinder portion 5 when it is moved up and down. Output information of the hydraulic gauge 63 and the position sensor 64 is sent to the control unit 65, and the control unit 65 determines whether the press-fitted state is good or not based on these information.

  As shown in FIG. 2, the press-fitting head portion 50 has a tapered shape that matches the shape of the tapered portion 31 (see FIG. 13) of the outer race 30, and the diameter decreases toward the tip. When the outer race 30 is press-fitted, the press-fitting head portion 50 passes through the tapered portion 31 of the outer race 30 and holds the outer race 30.

  Further, a rotary head portion 52 that is rotatable about the axial direction of the press-fit cylinder 5 is provided at the tip of the press-fit head portion 50. The rotary head portion 52 is connected to an air motor 51 built in the press-fit cylinder 5 and is rotatable about the axial direction of the press-fit cylinder 5. In addition, the rotational driving force from the air motor 51 is transmitted to the rotary head unit 52 via the clutch 53. When the torque from the air motor 51 reaches the specified torque, the clutch 53 is disconnected and the power transmission is interrupted. That is, a mechanism such as an impact wrench is provided.

  The press-fitting device 100 includes a back pressure gauge 54 that measures the back pressure during operation of the air motor 51. The output information of the back pressure gauge 54 is sent to the control unit 65, and the control unit 65 determines the quality of the press-fitted state in more detail based on this information. Details of the criteria will be described later.

  Further, as shown in FIG. 3, the outer peripheral portion of the rotary head portion 52 is provided with a key portion 55 that protrudes to the outer diameter side, and a ball portion 56 that can be inserted into and removed from the rotary head portion 52. ing. The ball portion 56 is biased outward by a biasing member such as a push spring, and is pushed inward when the plate 21 is attached or detached, for example.

  Further, a ring-shaped plate 21 is sandwiched between the outer race 30 and the case 10. As shown in FIG. 4, the inner diameter wall of the plate 21 is provided with a notch 22 that meshes with the key portion 55 of the rotary head portion 52. Therefore, as shown in FIG. 5, the rotary head portion 52 meshes the key portion 55 with the notch portion 22 of the plate 21, and the ball 56 holds the plate 21.

  For example, SUS material can be applied to the plate 21, and the outer diameter thereof is equal to the outer diameter of the outer race 30, and the inner diameter thereof is larger than the diameter of the opening 32 (see FIG. 13) on the plate 21 side of the outer race 30. small. The plate 21 also functions as a position adjusting function for adjusting the preload torque. Therefore, the plate thickness of the plate 21 varies depending on the desired preload torque.

  Next, a procedure for press-fitting the outer race 30 by the press-fitting device 100 will be described. In the press-fitting of the outer race 30, as shown in FIG. 6, first, the transaxle case 10 is set at a predetermined position on the work support 60. The outer race 30 is set on the press-fitting head portion 50 of the press-fitting cylinder 5. Further, the plate 21 is held by the rotary head 52 while the outer race 30 is held.

  Next, the outer race 30 and the plate 21 are press-fitted into the mounting opening 11 of the case 10 with the press-fitting head portion 50 holding the outer race 30 and the plate 21. As a result, as shown in FIG. 7, the outer plate 30 is fed to the end surface 12 of the case 10 (the bottom surface 12 of the mounting opening 11) with the plate 21 interposed therebetween.

  After the outer plate 30 is press-fitted, the press-fitting device 100 of this embodiment guarantees the press-fitted state by the following two types of press-fitting state determination methods. First, as the first press-fit state determination, output information of the hydraulic gauge 63 and the position sensor 64 is acquired, and whether the press-fit state is good or not is determined based on these information. That is, when at least one of the press-fitting thrust and the press-fit depth becomes defective, it can be determined that the outer race 30 is not press-fitted to the end face 12. Therefore, press-fitting is continued until both the press-fitting thrust and the press-in depth are satisfied. Alternatively, it is determined that the press-fit is defective, and the workpiece is removed. As a result, the press-fitted state until the gap of about the allowable value of the dimensional tolerance of the workpiece is obtained is guaranteed.

  Next, as the second press-fitting state determination, the air motor 51 tries to rotate the rotary head unit 52. At this time, as shown in FIG. 8, if the outer race 30 is press-fitted to the end surface 12, the plate 21 is sandwiched between the case 10 and the outer race 30. Therefore, the rotary head 52 fitted to the plate 21 cannot rotate due to the frictional resistance of both contact surfaces, and a back pressure greater than a predetermined value is measured. On the other hand, if the outer race 30 is not press-fitted to the end surface 12 as shown in FIG. 9 or if the outer race 30 is press-fitted with the foreign object 90 sandwiched as shown in FIG. . Therefore, the frictional resistance is small, the rotary head portion 52 rotates, and a back pressure exceeding a predetermined value is not measured. That is, the press-fit state can be determined from the measured back pressure value. Therefore, press-fitting is continued until the rotary head 52 stops rotating. This guarantees the press-fitted state up to a gap that is less than the dimensional tolerance of the workpiece. In consideration of the mixing of foreign matter as shown in FIG. 10, if the press-fit continues to a certain extent and the rotation does not stop, the work is removed as a press-fit failure.

  Subsequently, the second press-fitting state determination will be described in detail using specific numerical values. In the second press-fit state determination, if the plate 21 is in close contact with the outer race 30 and the case 10, the press-fit quality is more strictly guaranteed by utilizing the fact that the frictional resistance when the plate 21 is rotated is large. To do.

That is, as shown in FIG. 11, one is a rotating body, the other is a fixed body, the outer diameter and the inner diameter of the rotating body and the fixed body are equivalent, the friction coefficient is μ, and the pressing force of the fixed body on the rotating body The torque T that tries to stop the rotation when f is expressed by the following equation (1).

The dimensions of the outer race 30, the plate 21 and the case 10 of this embodiment are as shown in FIG. 12, the friction coefficient μ between the plate, the outer race, the plate and the case is 0.2, and the residual pressure generated by the press fitting of the outer race 30 When f is 0.0463 (kg / mm ² ), the frictional resistance torque Tm that tries to stop the rotation of the plate 21 is about 15.6 Nm.

  Therefore, the air motor 51 is adjusted so that the rotary head 52 has a rotational torque of 15.6 Nm or less. For example, when the rotational torque by the air motor 51 is 10.0 Nm, it is possible to perform an accurate quality determination using the following pattern.

  First, as shown in FIG. 8, when the outer race 30 is press-fitted to the end face 12, the frictional resistance torque is 15.6 Nm. That is, the output torque of the air motor 51 is greater than 10.0 Nm. Therefore, the rotary head unit 52 does not rotate, and the compressed air is exhausted without being used for the rotation of the rotary head 52. Therefore, the back pressure of the air motor 51 increases. That is, a back pressure of a predetermined value or more is detected, and it can be confirmed that the outer race is press-fitted to the end face 12 by detecting such back pressure.

  On the other hand, as shown in FIG. 9, when the outer race 30 is not press-fitted to the end surface 12 (case 1), the plate 21 is not in contact with the outer race 30 or the end surface 12, and the frictional resistance torque is 0 Nm. That is, the output torque of the air motor 51 is smaller than 10.0 Nm. Therefore, the rotary head part 52 of the press-fitting head part 50 rotates, and the compressed air is used for the rotation of the rotary head 52. Therefore, the back pressure of the air motor 51 does not increase. That is, it can be confirmed that the outer race is not press-fitted to the end face 12 because the back pressure exceeding the predetermined value is not detected and the back pressure exceeding the predetermined value is not detected.

  If the gap between the outer race 30 and the plate 21 after press-fitting or the gap between the plate 21 and the end surface 12 of the case 10 after press-fitting is larger than the dimensional tolerance (0.3 mm in this embodiment), the first It can be easily detected by determining the press-fit state. Therefore, the second press-fitting state determination is particularly effective when the gap is less than the dimensional tolerance.

  In addition, as shown in FIG. 10, when the outer race 30 is press-fitted with the foreign object 90 sandwiched (case 2), for example, when a foreign object having a width of 2.5 mm is sandwiched and the contact area is reduced to about 1/2, The frictional resistance torque is about 7.8 Nm. That is, the output torque of the air motor 51 is smaller than 10.0 Nm. Therefore, even in such a case, the rotary head portion 52 of the press-fitting head portion 50 rotates and the back pressure of the air motor 51 does not increase. That is, it is possible to confirm that the outer race 30 is not press-fitted to the end face 12 because the back pressure exceeding the predetermined value is not detected and the back pressure exceeding the predetermined value is not detected.

  That is, in the press-fitting device 100 of the present embodiment, a case where the gap between the outer race 30 and the plate 21 is a dimensional tolerance or less as in the case 1 described above, or a minute foreign object such as the case 2 is sandwiched. In this case, it cannot be extracted by the first press-fitting state determination (conventional method). Thus, by performing the second press-fitting state determination, a slight press-fitting failure as in the cases 1 and 2 is detected.

  In this embodiment, the final confirmation of the press-fitted state is performed based on the back pressure of the air motor 51, but the present invention is not limited to this. That is, any method can be used as long as it can determine whether or not the rotary head unit 52 is rotating. For example, the press-fit state may be determined by directly detecting the rotation amount of the rotary head unit 52.

  As described above in detail, the press-fitting device 100 of this embodiment holds the outer race 30 by the press-fitting head unit 50 and further holds the plate 21 by the rotary head unit 52 located at the tip of the press-fitting head unit 50. It is said. That is, the plate 21 moves as the rotary head unit 52 rotates. In this state, the outer race 30 together with the plate 21 is press-fitted into the case 10, and the rotary head portion 52 is driven to rotate in a state where the outer race 30 is press-fitted. At this time, if the outer race 30 is normally press-fitted, the rotating portion of the plate 21 does not rotate. On the other hand, if not press-fitted normally, the plate 21 will rotate. That is, if the press-fitted state is normal, the plate 21, the outer race 30, and the case 10 are in close contact with each other, and the frictional resistance is high. Therefore, it is possible to determine whether the press-fitted state is good or not based on whether or not the plate 21 (rotating head portion 52) is rotating by using this rotational frictional resistance. Therefore, in the press-fitting device 100 of the present invention, the press-fitting state can be determined from the actual contact state between the plate 21 and the outer race 30 and the close-contact state between the case 10 and the plate 21, and the press-fitting state is estimated from the press-fitting thrust and the press-fitting depth. Compared with the conventional technology, the press-fit to the specified position is more strictly guaranteed. Therefore, a press-fitting device and a press-fitting method capable of strictly guaranteeing that the press-fitting member is press-fitted to a specified position are realized.

  Further, the plate 21 has a function as a shim member that adjusts the position of the outer race 30 in the press-fitting direction. That is, when the outer race 30 is press-fitted into the case 10, a position adjusting member such as a shim is used to adjust the dimensional error between the two. Thus, the plate 21 also serves as a position adjustment function, so that the press-fit state can be assured with high accuracy without increasing the number of parts.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the present embodiment, the second press-fitting state determination is performed after the first press-fitting state determination, but only the second press-fitting state determination may be performed. In this case, for example, the rotary head unit 52 may be rotated before press-fitting, press-fitted while rotating, and the press-fitting may be continued until the rotation stops.

It is a figure which shows schematic structure of the press injection apparatus concerning embodiment. It is a figure which shows the structure of the press-fit head part of the press-fit apparatus concerning embodiment. It is a figure which shows the AA cross section of FIG. It is a figure which shows the structure of the plate for preload adjustment concerning embodiment. It is a figure which shows the state in which the press-fit head part hold | maintained the plate for preload adjustment. It is a figure which shows the state at the time of press-fitting of an outer race (before press-fitting). It is a figure which shows the state at the time of press-fitting of an outer race (after press-fitting). It is a figure which shows the state (normal state) in which the outer race was press-fit to the bottom face. It is a figure which shows the state (abnormal state) where the outer race is not press-fitted to the bottom surface. It is a figure which shows the state (abnormal state) in which the outer race was press-fitted with a foreign object in between. It is a figure which shows the concept of each parameter of the calculation formula of frictional resistance torque. It is a figure which shows the dimension of each parameter. It is a figure which shows the combined state of the case of a transaxle, and a tapered roller bearing. It is a figure which shows the state with which the tapered roller bearing was combined with the case of the transaxle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Case 11 Mounting opening 12 End surface 21 Plate 22 Notch 30 Outer race 5 Press-fit cylinder 50 Press-fit head part 51 Air motor 52 Rotating head part 53 Clutch 55 Key part 100 Press-fit device

Claims (6)

In a press-fitting device for press-fitting a press-fitting member having a through hole into a predetermined bottomed hole provided in a workpiece with a plate member interposed therebetween,
A press-fit shaft provided movably in the press-fit direction of the press-fit member;
A press-fitting head portion that is located at the tip of the press-fitting shaft and holds the press-fitting member through a through-hole of the press-fitting member;
A rotary part located at the tip of the press-fitting head part, detachably fitted to the plate member, and provided rotatably about the axial direction of the press-fitting shaft;
A drive unit for rotationally driving the rotary unit;
A press-fitting device, comprising: a press-fitting state diagnosis unit that detects a rotation state of the rotary part and determines whether or not the press-fitting state of the press-fitted member is good based on the detection result. The press-fitting device according to claim 1,
The press-fitting device, wherein the plate member is a shim member that adjusts a position of the press-fitting member in a press-fitting direction. The press-fitting device according to claim 1 or 2,
The drive unit includes an air motor,
The press-fitting device is characterized in that the press-fitting state diagnosis unit detects a back pressure of the air motor, and determines that the rotating unit is not rotating if the back pressure of the air motor is a predetermined value or more. In a press-fitting method for press-fitting a press-fitted member having a through hole into a predetermined bottomed hole provided in a workpiece with a plate member interposed therebetween,
The press-fitting head is positioned through the through-hole of the press-fitting member at a press-fitting head portion located at the tip of a press-fitting shaft that is provided so as to be movable in the press-fitting direction of the press-fitting member. A press-fitting step of holding the plate member at the rotating part positioned and press-fitting the press-fitted member into the bottomed hole of the workpiece together with the plate member;
A rotation step for rotationally driving the rotating portion in a state where the press-fitting member is press-fitted,
A press-fitting method, comprising: a press-fitting state diagnosing step of detecting a rotation state of the rotating part and judging whether or not the press-fitted state of the press-fitted member is good based on the detection result. In the press-fitting method according to claim 4,
The press-fitting method, wherein the plate member also has a function of adjusting a position of the press-fitting member in a press-fitting direction. In the press-fitting method according to claim 4 or 5,
In the rotating step, the rotating part is driven to rotate by an air motor,
In the press-fitting state diagnosis step, the back pressure of the air motor is detected, and if the back pressure of the air motor is not less than a predetermined value, it is determined that the rotating part is not rotating.

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