JPH0739015B2 - Coil spring setting device and setting method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a setting device and a setting method for a coil spring used in, for example, a suspension spring for a vehicle.

[0002]

2. Description of the Related Art The setting performed in the manufacture of springs is an important step because it has the effect of raising the elastic limit of the spring and improving the yield strength by work hardening, thereby increasing the use limit against static load. In the conventional setting method, at the spring manufacturing site, the setting height or setting load is determined for each product number, and fine adjustment is performed for each lot to stabilize the quality.

[0003]

However, in reality, there is a slight load variation for each spring in the same lot, and there is a defective load product under the present circumstances. It is considered that there are mainly two causes described below, which cause load variations within a lot.

(1) Variation due to processing before setting (for example, tempering hardness and spring shape) (2) Variation of setting machine itself (for example, variation of cylinder stroke) In addition, in order to improve the sag resistance of the coil spring. , Warm setting may be performed. The warm setting is to perform the setting at a temperature of about 150 to 250 ° C. by utilizing the residual heat after tempering of the coil spring. In the case of such warm setting, in addition to the above two causes, 3) Variation in setting temperature (4) Variation in temperature drop during setting is considered.

The present invention has been made in consideration of the above-mentioned causes, and an object thereof is an apparatus and a setting method capable of performing appropriate setting for each coil spring and suppressing load variations after setting. To provide.

[0006]

The setting device of the present invention developed to achieve the above object comprises a load measuring means for measuring a load of a coil spring before setting which is compressed to a predetermined height, and the above load. And a variable setting machine for changing the setting height or the setting time based on the load measurement value measured by the measuring means.
Further, the setting method of the present invention is
The coil spring is compressed in advance to a specified height and the load
Is measured and set in the setting process that follows.
Hold the setting time constant and set the setting height to the above load.
Change according to the measured value or set the setting height.
Keep the setting time constant and set according to the above load measurement value.
By changing it, the load after setting becomes constant.
It is characterized by controlling so that.

[0007]

Before the setting, the coil spring is compressed to a predetermined height and the load at that time is measured by the load measuring means. In the setting process performed after that, the load after setting can be changed by changing the setting time with the setting height kept constant or the setting height changed depending on the load measurement value. Suppress the occurrence of variations.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Setting device 1 in the illustrated example
0 is the terminal positioning stage 11, the load measuring stage 12, the setting stage 13, and the work transfer mechanism 1
4 and a control unit 15 using a personal computer or the like. The stages 11, 12, and 13 in the illustrated example are
It is provided on the bases 16 and 17.

The terminal positioning stage 11 is provided with actuators 22 and 23 provided with positioning jigs 20 and 21 facing each other so that the coil spring A (shown in FIG. 2) as a work is wound around the terminal end portion. Positioning is done. The coil spring A is positioned, for example, at the winding end in the rotational direction by the jigs 20 and 21 rotating relative to each other.

The load measuring stage 12 is provided with a pair of terminal holders 30 and 31 provided so as to face each other.
One terminal holder 30 is movable in the axial direction by a cylinder mechanism 32 such as a hydraulic cylinder. The terminal holder 30 is provided with a load sensor 33 such as a load cell as an example of load measuring means.

The other terminal holder 31 is provided with a cylinder mechanism 35 such as a hydraulic cylinder and a ball screw mechanism 36.
It can be reciprocally driven along the guide 37 in the axial direction with a predetermined stroke. In order to improve the positional accuracy of the terminal holder 31, the cylinder mechanism 35 is operated with a full stroke. The position of the terminal holder 31 is accurately regulated by the ball screw mechanism 36. An example of the ball screw mechanism 36 includes a stepping motor 40, an electromagnetic brake 41, and the like.

The setting stage 13 is provided with a pair of terminal holders 45 and 46 provided so as to face each other. One terminal holder 45 is movable in the axial direction by a cylinder mechanism 47 such as a hydraulic cylinder. The other terminal holder 46 can be reciprocally driven along the guide 51 with a predetermined stroke in the axial direction by a variable setting machine 50 including a cylinder mechanism 48 such as a hydraulic cylinder and a ball screw mechanism 49. ing. The cylinder mechanism 48 is operated with a full stroke to increase the positional accuracy. The position of the terminal holder 46 is accurately regulated by the ball screw mechanism 49. An example of the ball screw mechanism 49 includes a stepping motor 55, an electromagnetic brake 56, and the like.

The work transfer mechanism 14 is for transferring the coil spring A between the stages 11, 12 and 13. A program for implementing various setting patterns described later is incorporated in the control unit 15, and the operation of each stage 11, 12, 13 is controlled by a predetermined procedure.

Next, a warm setting method using the setting device 10 will be described. FIG. 3 schematically shows the relationship between the elapsed time and the spring height in the warm setting process. Coil spring A that has been tempered to a specified hardness and has exited the tempering furnace at a specified temperature
Is first adjusted to a predetermined posture on the terminal positioning stage 11 and then sent to the load measuring stage 12 by the transport mechanism 14. In the load measuring stage 12, the coil spring A is compressed to a preset height (Hm), and the load at that time is measured. The designated height (Hm) at the time of measuring the load can be finely adjusted by the ball screw mechanism 36.

After the load measurement, the coil spring A is sent to the setting stage 13 and is held at an appropriate variable setting height (Hb) for a certain period of time (t) according to the load measurement value described above. Done. The data used as the basis for determining the setting height (Hb) is divided into, for example, 10 ranks with respect to a certain fixed reference value, and the control unit 15 is provided.
Remember. And based on the load measurement value described above,
An appropriate setting height (Hb) is set according to the rank. That is, in this setting pattern (FIG. 3), the setting time (t) is constant and the setting height (Hb)
The variable setting machine 50 is controlled to variably set. The setting height (Hb) can be finely adjusted by the ball screw mechanism 49. The load of the coil spring A after setting is measured at a predetermined height (Hc).

According to the above-mentioned setting process, the process capability index Cp of the coil spring of a certain product number is increased from 1.2 to 3.0 as compared with the case where the conventional setting method is carried out, and the final product defect is caused. The rate has been reduced from about 2.5% in the past to about 1.3%.

The setting pattern shown in FIG. 4 shows a case where the setting time (t) is changed while keeping the setting height (Hb) constant in the warm setting step. In the case of this setting method, the coil spring A
After being adjusted to a predetermined posture on the terminal positioning stage 11, the load is measured at a preset height (Hm) on the load measuring stage 12 and further sent to the setting stage 13 to set a constant setting height. (H
Under b), the setting is performed at an appropriate time (t) that is changed according to the load measurement value described above. The data used as the basis for determining the setting time (t) in this case is divided into, for example, 10 ranks with respect to a certain reference value, and is stored in the control unit 15 in advance. Then, an appropriate setting time (t) corresponding to the rank is set based on the load measurement value described above. The coil spring A after setting is
The load measurement is performed at a predetermined height (Hc).

The load measuring stage 12 and the setting stage 13 may be combined. For example, by using a variable setting machine 61 having a load sensor 33 like the setting device 60 shown in FIG. 5, it is possible to perform load measurement and setting on the unified stage 62.

FIG. 6 shows a worm setting pattern using the above-mentioned setting device 60. The coil spring A that has been tempered to a predetermined hardness and exited from the tempering furnace at a predetermined temperature is sent to the common stage 62 after being adjusted to a predetermined posture in the terminal positioning stage 11 and set to a preset height. The load is measured at (Hm). The coil spring A after the load measurement is performed by the unified stage 62 at an appropriate variable setting height (H) according to the load measurement value.
In b), setting is performed for a fixed time (t). That is, the setting time (t) is constant and the setting height (H
b) is changed. The load of the coil spring A after setting is measured at a predetermined height (Hc).

The setting pattern shown in FIG. 7 is obtained by using the setting device 60 described above and setting height (Hb).
Shows a case where the setting time (t) is changed while keeping the value constant. In this setting method, the coil spring A
After the load is measured at the preset height (Hm) in the unified stage 62, the unified stage 62
At a constant setting height (Hb) under an appropriate variable setting time (t) according to the load measurement value.
Setting is performed in. Coil spring A after setting
Is measured at a predetermined height (Hc).

FIG. 8 shows another setting pattern performed by using the setting device 60. In this case, the coil spring A is held in a predetermined posture by the terminal positioning stage 11, then compressed to the contact height (Hb) in the unified stage 62, and the setting is performed at a constant time (t). After that, the load is returned to a predetermined height (Hm), the load at that time is measured, and this load measurement value is compared with a predetermined reference value to be processed in the following two cases.

1. If the load measurement value is equal to or less than the reference value, the load is immediately reduced as shown by the chain double-dashed line in FIG. 8, and the load is measured at the predetermined height (Hc).

2. If the measured load value is greater than the reference value, until the load value falls to the level of the reference value, or after continuing to apply the load for an appropriate time,
The load is reduced and the load is measured at a predetermined height (Hc).

Any of the above-mentioned setting patterns (FIGS. 3, 4, and 6) is applied to each coil spring, and the optimum setting can be performed on each coil spring, so that the variation in load after setting is greatly increased. Can be reduced to In particular, the effect is great in worm setting, which tends to cause load variations.

[0025]

According to the present invention, setting can be performed under optimum conditions one coil spring at a time, the load variation after the setting is reduced, and the final product defect rate is lower than that of the conventional one. Greatly reduced.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing the structure of a setting device according to an embodiment of the present invention.

FIG. 2 is a plan view showing an operation mode of the setting device shown in FIG.

FIG. 3 is a diagram showing an example of a setting process performed by the apparatus shown in FIG.

FIG. 4 is a diagram showing another example of the setting process by the apparatus shown in FIG.

FIG. 5 is a plan view schematically showing the structure of a setting device according to another embodiment of the present invention.

FIG. 6 is a diagram showing an example of a setting process by the apparatus shown in FIG.

FIG. 7 is a diagram showing another example of the setting process by the apparatus shown in FIG.

FIG. 8 is a view showing still another example of the setting process by the apparatus shown in FIG.

[Explanation of symbols]

A ... Work (coil spring), 10 ... Setting device, 1
1 ... Terminal positioning stage, 12 ... Load measuring stage,
13 ... Setting stage, 15 ... Control part, 50, 61
… Variable setting machine.

Claims (3)

[Claims] 1. A load measuring means for measuring a load in a state where a coil spring before setting is compressed to a predetermined height, and a setting height or a setting time is changed based on a load measurement value measured by the load measuring means. A setting device for a coil spring, comprising: 2. A coil spring is compressed to a predetermined height in advance before setting, and a load at that time is measured, and a setting time is made constant in a setting step performed thereafter, and the setting height is set according to the load measurement value. A method for setting a coil spring, characterized in that the load after setting is controlled to be constant by changing the value by changing the value. 3. A coil spring is compressed to a predetermined height in advance before setting, and the load at that time is measured, and the setting height is made constant in the setting step performed thereafter, and the setting time is set according to the load measurement value. A method for setting a coil spring, characterized in that the load after setting is controlled to be constant by changing the value by changing the value.