JP4252099B2 - Method and apparatus for determining whether or not press fit is good - Google Patents

Description

  The present invention relates to a determination method and a determination apparatus that determine whether or not press-fitting is good.

  In general, when the work member is press-fitted, the cylinder is driven to move the plunger while the work member is placed at the press-fitting position of the press-fitted member. The press-fit member has a press-cut end that is a contact surface of the work member, and the plunger has a press-fit determination section from the press-fit start position to the press-fit end position until the lower end surface of the work member contacts the press cut end. Moving.

  In the conventional determination method, the thrust of the cylinder, that is, the pressure input of the work member by the plunger is detected in the press-fitting determination section. Further, the maximum peak and the minimum peak of the thrust are detected, and whether the press fit is good or bad is determined based on the maximum peak and the minimum peak.

  However, according to this conventional determination method, it is not possible to detect the pressure input at a position close to the press-cut end, and therefore it is not possible to accurately determine whether or not the press-fit is good. On the other hand, the present applicant has proposed an improved determination method according to Patent Document 1. According to this, the thrust information and position information of the plunger is acquired, the position where the rate of change of the thrust information relative to the position information is a predetermined magnitude or more is detected as the position immediately before the press-fit end, and based on the position immediately before the press-fit end The determination end position is determined, and whether or not the press-fitting is determined is determined by whether or not the thrust information is within a predetermined range between the predetermined determination start position and the determination end position during press-fitting.

As a result, it is possible to detect a pressure input at a position as close as possible to the press-cut end, and it is possible to more accurately determine whether or not the press-fitting is good.
JP 2000-158244 A

  However, in the conventional determination method described above, whether the press-fitting is good or bad is determined only in the vicinity of the determination end position, and thus it cannot be detected whether there is any abnormality during the press-fitting process.

  Therefore, for example, in the middle of the press-fitting process, it is not possible to detect foreign object biting, workpiece member catching or galling. Conventionally, when any determination is performed during the press-fitting process, a check point for such determination is set based on the distance from the start of press-fitting. However, the distance from the press-fitting start position to the press-fitting end position varies depending on the work member, and varies depending on the time-dependent change of the press-fitting device.

  For this reason, the determination condition set for each check point may not match the actual state of each work member, and therefore accurate determination may not be possible.

The present invention has been made in view of the above-described problem, and an upper limit value and a lower limit value are set for each of a plurality of check points with the determination end position as a base point. The purpose is to eliminate inaccuracies and make an accurate press-fitting determination.

The method according to the present invention is a method of determining whether or not a press fit is good when a work member is press-fitted into a press-fit member having a cut-off end by a linearly driven plunger, and the plunger press-fits the work member. In the predetermined stroke range, the plunger thrust information and position information are acquired, and the determination end position is determined based on the position immediately before the press-fitting end where the rate of change of the thrust information with respect to the position information is equal to or greater than a predetermined magnitude. Then, after the determination end position is determined, a plurality of positions that are reversed by a plurality of set distances are set as checkpoints, with the determination end position as a base point , and each of the plurality of checkpoints is set . For each checkpoint, an upper limit value and a lower limit value are set for each checkpoint. When in the range defined by the stomach set the upper limit value and the lower limit value, it is determined that the press fitting is good.

According to the present invention, by setting an upper limit value and a lower limit value for each of a plurality of check points with the determination end position as a base point , it is possible to eliminate inaccuracies in determination due to variations in workpieces and the like, and to perform accurate press-fitting determination It can be performed.

  FIG. 1 is a diagram showing a configuration of a press-fitting system PF using a determination device 1 according to the present invention, FIG. 2 is a diagram for explaining an operation in the determination device 1, and FIG. 3 is an enlarged view of a main part of FIG. FIG. 2 and 3, the vertical axis represents the thrust TH of the cylinder CY, that is, the pressure input by the plunger PR, and the horizontal axis represents the position LL of the plunger PR.

  As shown in FIG. 1, the press-fitting system PF includes a press-fitting device, a determination device 1, a sequencer 18, and the like. The press-fitting device includes a cylinder CY, a load cell 11, a position sensor 12, and the like. The determination apparatus 1 includes amplifiers 13 and 14, an arithmetic processing unit 15, a setting unit 16, a memory 17, and the like. The determination apparatus 1 can be configured using a CPU, a ROM and a RAM in which appropriate programs are stored, other memories, peripheral elements, an appropriate hardware circuit, and the like.

  A plunger PR is attached to the tip of the piston rod PD of the cylinder CY. A press-fit member BZ is disposed below the cylinder CY. In a state where the work member WK is placed at the press-fitting position AP of the press-fit member BZ, the cylinder CY is driven to move the plunger PR downward, thereby press-fitting the work member WK into the press-fit member BZ. The press-fit member BZ has a pressing end KT which is a contact surface of the work member WK, and the plunger PR is pressed from the press-fitting start position LL1 until the lower end surface of the work member WK comes into contact with the press-cut end KT. The press-fitting section RA up to the position LLE is moved.

  The load cell 11 is attached in the middle of the piston rod PD, and detects the thrust TH of the cylinder CY, that is, the pressure input of the work member WK by the plunger PR. The amplifier 14 amplifies the output signal of the load cell 11 and outputs a thrust signal S1.

  The position sensor 12 detects the position LL of the plunger PR and the workpiece member WK by detecting the position of the piston rod PD in the cylinder CY. The amplifier 13 outputs a position signal S2 based on the output from the position sensor 12.

  The calculation processing unit 15 includes a position detection calculation unit 15a immediately before the press-fitting end, a determination calculation unit 15b, and a range setting unit 15c. The determination of whether the press-fitting is good or not, immediately before the lower end portion of the work member WK comes into contact with the cut-off end KT. The control signal CS is sent to the sequencer 18. The processing contents of the arithmetic processing unit 15 will be described later.

  The setting unit 16 includes a data acquisition start position LL2, a determination start position LLH and a distance LA, a press-fit end position determination range RE, a maximum thrust reference value FFH, a minimum thrust reference value FFL, a press-fit end thrust determination value FFB, and a press-fit. This is for setting each value such as the slope BPI just before the end.

  Further, the setting unit 16 can set the determination positions P1, P2, P3... During the press-fitting process, the upper limit values H1, H2, H3..., And the lower limit values L1, L2, L3. Each of them may be described as “determination position P”, “upper limit value H”, and “lower limit value L”.

  The data acquisition start position LL2 is the position of the plunger PR when the memory 17 starts storing the thrust signal S1 and the position signal S2. That is, data from the data acquisition start position LL2 to the press-fitting end position LLE (data acquisition section RM) is stored in the memory 17.

  The determination start position LLH is the position of the plunger PR when the determination of whether or not press-fitting is started. The determination start position LLH is a position before the determination end position LLQ described later by a distance LA. Whether or not the press-fitting is good is determined by whether or not the magnitude of the thrust signal S1 is within a predetermined range in the determination section RD from the determination start position LLH to the determination end position LLQ during the press-fitting.

  The press-fit end position determination range RE determines whether or not the press-fit end position LLE is within this range, and thereby determines whether or not the press-fit end position LLE, that is, the press-cut end is a normal position.

  The maximum thrust reference value FFH is the maximum value of the thrust signal that serves as a determination criterion when determining that the press-fit is “good”. The minimum thrust reference value FFL is the minimum value of the thrust signal that serves as a determination reference when determining that the press-fit is “good”. The inclination BPI immediately before the press-fit end is a reference value for determining whether or not the lower end portion of the work member WK is immediately before the press-fit end KT comes into contact.

  The press-fit end thrust determination value FFB is a reference value for determining whether the pressure input by the plunger PR has reached the maximum value FFM of the thrust CY of the cylinder CY, and when the press-fit end thrust determination value FFB is exceeded. It is determined that the maximum value FFM has been reached. When the press-fit end thrust determination value FFB is exceeded, the press-fit end position LLE, that is, the pressing end KT, has been normally reached.

  The determination position P is a check point for checking whether or not the press-fitting process is proceeding normally during the press-fitting process. These determination positions P are set based on the distance to be reversed from the determination end position LLQ described above as a base point. In other words, each determination position P is a position that is reversed from the determination end position LLQ by a set distance. Accordingly, the determination position P is not determined unless the determination end position LLQ is determined.

  The upper limit value H and the lower limit value L are values that determine the range of normal pressure input at each determination position P. That is, when the pressure input represented by the thrust signal S1 is within the range determined by the upper limit value H and the lower limit value L at each determination position P, the press-fitting process at the determination position P is proceeding normally. Determined. When all the determination positions P are normal, it is determined that the press-fitting process has proceeded normally.

  Thus, determining whether or not the press-fitting process is normal at each determination position P is a technical feature in the present embodiment. Furthermore, each determination position P may be based on the determination end position LLQ measured for each work member WK, instead of using the fixed position such as the press-fitting start position LL1 or the press-cut end KT. It is a technical feature in the form. As a result, inaccuracies in determination due to variations in the workpiece member WK are eliminated, and accurate press-fitting determination is performed. Details will be described later.

  The memory 17 includes a thrust signal storage unit 17a, a position signal storage unit 17b, and a set value storage unit 17c. The thrust signal storage unit 17a stores the thrust signal S1 in the data acquisition section RM from the data acquisition start position LL2 to the press-fitting end position LLE in the thrust signal S1. The position signal storage unit 17b stores the position signal S2 in the data acquisition section RM among the position signals S2. The position signal S2 and the thrust signal S1 are stored in association with each other.

  The set value storage unit 17c includes the data acquisition start position LL2, the determination start position LLH, the press-fit end position determination range RE, the maximum thrust reference value FFH, the minimum thrust reference value FFL, and the press-fit end thrust determination value FFB set by the setting unit 16. , The inclination BPI immediately before the end of press-fitting, the determination position P, the upper limit value H, the lower limit value L, and the like are stored.

  The sequencer 18 performs overall control of the press-fitting system PF based on the control signal CS sent from the arithmetic processing unit 15. Next, the operation and processing of the arithmetic processing unit 15 will be described.

  The position detection calculation unit 15a immediately before the press-fitting end detects a position where the rate of change (change rate) RS of the thrust signal S1 with respect to the position signal S2 is equal to or greater than the slope BPI immediately before the press-fitting end as a position LLP immediately before the press-fitting end in the data acquisition section RM To do. The value of the slope BPI immediately before the end of press-fitting is tan θ1 in FIG. In order to obtain the ratio RS, for example, the slope of the straight line may be obtained based on a plurality of continuous data respectively stored in the thrust signal storage unit 17a and the position signal storage unit 17b.

  It can be said that the position LLP immediately before the end of press-fitting is a position where the lower end surface of the work member WK starts to come into contact with the pressing end KT. Next, the determination end position LLQ is determined based on the position LLP immediately before the press-fitting end. In the present embodiment, the position LLP immediately before the end of press-fitting and the determination end position LLQ coincide. A determination start position LLH that is a predetermined distance LA before the determination end position LLQ is obtained. The distance LA is set to about 0.1 mm, for example.

  In the determination section RD from the determination start position LLH to the determination end position LLQ, the determination calculation unit 15b includes the thrust signal S1 stored in the thrust signal storage unit 17a, the maximum thrust reference value FFH stored in the set value storage unit 17c, and The magnitude is compared with the minimum thrust reference value FFL. When the thrust signal S1 is not less than the minimum thrust reference value FFL and not more than the maximum thrust reference value FFH, it is determined that the work member WK has been press-fitted with a predetermined pressure input.

  Further, when the thrust TH of the cylinder CY exceeds the press-fit end thrust determination value FFB and the press-fit end position LLE is within the press-fit end position determination range RE, it is determined that the press-fit is normally performed. Then, the result of the press-fitting is set to “good” and a control signal CS to that effect is output.

  The sequencer 18 outputs an instruction AS necessary for the next press-fitting to the cylinder CY or the like in real time based on the control signal CS. As described above, whether the result of the press-fitting is good or bad is determined in the determination interval RD based on the thrust signal S1 and the position signal S2 stored in the memory 17 in the data acquisition interval RM. Therefore, it is possible not only to compare the minimum or maximum peak point with the reference value as in the prior art, but also to determine the entire stored data, and it is possible to accurately determine the quality of press-fitting.

  Further, in determining the determination end position LLQ, the ratio RS of the thrust signal S1 to the position signal S2 is compared with the inclination BPI immediately before the press-fit end to obtain the position LLP immediately before the press-fit end, and is determined based on the position LLP immediately before the press-fit end. Yes. That is, the determination end position LLQ is not fixedly determined, but the actual press-fitted state is detected, the position at which the workpiece member WK starts to contact the pressing edge KT is measured, and the result of the measurement is It is determined based on this. Therefore, the determination end position LLQ can be brought as close as possible to the actual pressing edge KT, and the pressure input can be detected as close to the pressing edge KT. Therefore, it is possible to accurately determine whether or not the press fitting is good.

  In some cases, the plurality of workpiece members WK are continuously press-fitted so as to contact each other in the press-fitting direction. For example, a plurality of bearings may be sequentially press-fitted. In such a case, since the tolerance of the bearing width dimension is accumulated, if the determination end position is fixedly determined as in the prior art, it is difficult to make an accurate determination due to the influence of the accumulated tolerance. However, according to the determination apparatus 1 of the present embodiment, the determination end position LLQ is determined based on the actual measurement result of the position at which the work member WK starts to contact the press-cut end KT. It is possible to accurately determine whether or not the press-fitting is performed without causing an adverse effect due to the accumulation of tolerances. In other words, the press-fit end position determination range RE of the next continuous workpiece member WK may be set based on the press-fit end position LLE obtained by actual measurement. Judgment is made.

  Furthermore, in the present embodiment, in order to more accurately determine whether or not the press fitting is good, it is checked whether or not the press fitting process has proceeded normally as described above. In FIG. 3, each determination position P is determined using the determination end position LLQ as a base point after the determination end position LLQ is determined. At each determination position P, a position signal S2 corresponding to the determination position P is extracted, and a pressure input is acquired from the thrust signal S1 corresponding thereto. If the pressure input at each determination position P is within the range determined by the respective upper limit value H and lower limit value L, it is determined that the press-fitting process has proceeded normally. If the pressure input does not fall within the range at any determination position P, it is determined that there is some abnormality in the press-fitting process.

  And based on all the determination results described above, the quality of press fit is determined comprehensively. Thus, according to the determination apparatus 1 of this embodiment, the reliability of the press-fitting quality determination can be improved.

  FIG. 4 is a diagram illustrating an example of a change in the thrust signal S1 when applied to another workpiece member WK. In FIG. 4, the thrust signal S1 draws a smooth curve, and the press input increases between the press-fit start position LL1 and the press-fit end position LLE as the press-fit progresses.

  In this case, the data acquisition start position LL2 is a position before the press-fitting start position LL1. Although the cut end KT is applied as the press-fit end position LLE, as described above, the determination end position LLQ may be applied.

  Determination positions P1 to 10 are set at 10 locations, and an upper limit value H and a lower limit value L are set for each determination position P. When the pressure input at each determination position P is within the range determined by the upper limit value H and the lower limit value L, it is determined that the press-fitting process has proceeded normally. An arbitrary number of determination positions P may be set.

  As described above, by determining whether or not the press-fitting process has proceeded normally, it is possible to detect a foreign object biting into the workpiece member WK, a catching or galling of the workpiece member WK, and the like. In determining the determination position P, since the press-fit end position LLE of the work member WK is used as a base point, there is no variation in determination due to variations in the push-off end (press-fit end) KT, and accurate press-fitting determination is performed.

  In setting the determination position P, the upper limit value H, and the lower limit value L, the user operates the operation panel and performs input on the display surface based on the display. The determination position P can be set by inputting the number desired by the user.

  In the above-described embodiment, the upper limit value and the lower limit value of the press-fitting distance are set, and it is further determined whether or not the distance from the press-fitting start position LL1 to the press-fitting end position LLE is within the set press-fitting distance range. You may judge.

  In the embodiment described above, the data acquisition section RM is set from the data acquisition start position LL2 to the press-fitting end position LLE. However, the data acquisition start position may be widened, for example, as the press-fitting start position LL1. Further, the data acquisition interval RM may be matched with the determination interval RD. The determination section RD may be further expanded.

  In the above-described embodiment, the determination end position LLQ is made to coincide with the position LLP immediately before the press-fitting end, but they may be different from each other. For example, the determination end position LLQ may be a certain dimension before the press-fit end position LLP. As a fixed dimension in that case, for example, a value of about 0.1 mm can be used.

  In the determination, the quality may be determined based on the waveform pattern of the position signal S2 and the thrust signal S1 in the determination section RD. The shape, size, material, and the like of the plunger PR can be various. Although the plunger PR is attached to the tip of the piston rod PD, it may be integrated with the piston rod PD. The load cell 11 may be attached to the head side of the cylinder CY. Further, the load cell 11 may be attached between the cylinder CY and the frame to which the cylinder CY is attached.

  In the above-described embodiment, the configuration, structure, size, shape, material, number, and the like of the entire determination device 1 and the press-fitting system PF or each part can be variously changed in accordance with the gist of the present invention.

It is a figure which shows the structure of the press injection system using the determination apparatus which concerns on this invention. It is a figure for demonstrating operation | movement in the determination apparatus which concerns on this invention. It is a figure which expands and shows the principal part of FIG. It is a figure which shows the example of the change of the thrust signal at the time of applying to another workpiece member.

Explanation of symbols

1 judgment device 11 load cell (thrust detection means)
12 Position sensor (position detection means)
15b Determination calculation part (determination means)
16 Setting part (means for setting)
17 Memory (memory means)
PR Plunger WK Workpiece member RM Data acquisition section (predetermined stroke range)
S1 Thrust signal (thrust information)
S2 Position signal (position information)
LLP press just before the end position LLQ determination end position location LLE press fitting end position location P determination position (check point)

Claims (2)

A method of determining whether or not press-fitting is good when a workpiece member is press-fitted into a press-fitted member having a press-cut end by a linearly driven plunger,
Obtaining the plunger thrust information and position information within a predetermined stroke range when the plunger press-fits the workpiece member;
A determination end position is determined based on a position immediately before the press-in end where the rate of change of the thrust information with respect to the position information is equal to or greater than a predetermined magnitude, and after the determination end position is determined, the determination end position is used as a base point. , Set multiple points as checkpoints that have gone up by multiple set distances,
The upper and lower limits set respectively to each of the plurality of check points,
When the thrust information at the check point is within a range determined by the upper limit value and the lower limit value set at each check point, it is determined that the press-fitting is good.
A method for determining whether or not the press fit is good. There is a device for judging whether or not the press-fitting is good when the work member is press-fitted into the press-fitted member having a press-cut end by a linearly driven plunger,
Thrust detecting means for obtaining thrust information in a predetermined stroke range of the plunger;
Position detecting means for obtaining position information in a predetermined stroke range of the plunger;
Storage means for storing the thrust information and the position information;
Means for detecting a position at which a rate of change of the thrust information with respect to the position information is a predetermined magnitude or more as a position immediately before the press-in end;
Means for determining a determination end position based on the position immediately before the press-fitting end;
Means for setting each of a plurality of positions ascending by a plurality of set distances as checkpoints, using the determination end position as a base point;
It means for setting upper and lower limit values, respectively for each of the plurality of check points,
Determination means for determining that the press-fitting is good when the thrust information at the check point is within a range determined by the upper limit value and the lower limit value set at each check point;
A press-fitting quality determination device characterized by comprising:

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