JPH02213714A - Substrate mounting structure for position detecting sensor - Google Patents

Abstract

PURPOSE:To prevent the positional deviation of a substrate by a temp. change by setting the position where the substrate is mounted to a case in proximity to the position where a slider and the case are mounted. CONSTITUTION:The slider 45 moves toward a cover 3 side while compressing a coil spring 5, when an object to be measured comes into contact with the front end 43a of a pin 43 for operating a movable member and moves further near to a sensor. A contact part 41a of a brush 41 on the resistor surface 1a of the substrate 1 moves together with the slider 4 and changes the resistance value of the substrate 1. Both the substrate 1 and the slider 4 are assembled to the case 2 side independently from the cover and the generation of an error by the fluctuation in the assembly position of the case 2 and the cover 3 is obviated. A stopper part 2d with which the substrate 1 comes into contact and an end face 21a of a bushing 21 with which the slider 4 comes into contact are in proximity to each other and, therefore, there is substantially no influence of the size change of the case 2 by the temp. change.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position detection sensor whose resistance value changes depending on the position of an object to be detected, and more particularly relates to a mounting structure of a substrate inside the position detection sensor. .

"Prior Art" A mounting structure for a substrate in a conventional position detection sensor will be described with reference to FIG.

The substrate 1 is made of a brittle material such as ceramic, and has a resistor surface 1a. An end portion 1b of the substrate 1 is cantilevered to the inside of a cover 3 that closes off the inside of the case 2. The slider 4 is formed by integrally molding a slider 45 and an operation pin 43, and is slidably held in the case 2. A brush 41 is fixed to the slider 45. A contact portion 41 a is provided at the tip of the brush 41 , and this contact portion 41 a slides on the resistor surface 1 a to change the resistance value of the substrate l. When the slider 45 comes into contact with the sensor and approaches the sensor, the slider 45 compresses the coil spring 5 and moves toward the cover 3 side.

"Problems to be Solved by the Invention" In the conventional substrate mounting structure for a position detection sensor having the above configuration, the substrate 1 is joined to the cover 3 and the slider 4 is held by the case 2.

For this reason, the substrate 1 and the slider 4 are directly affected by variations in assembly between the cover 3 and the case 2, and there is a problem in that variations between individual sensors are unavoidable.

In addition, since the bonding position of the substrate 1 and the holding position of the slider 4 are far apart, temperature changes may cause the substrate 1 and the slider 4 to move. In case 2, etc., the relative position of the contact portion 41a and the resistor surface 1a deviates between the high temperature and low temperature due to the dimensional change of each component, which has a different coefficient of thermal expansion and a large difference in the reference position of expansion and contraction, resulting in a large error. There was a problem.

Since the substrate 1 made of a brittle material is joined to the cover 3 in a cantilever shape, the substrate 1
There was a problem in that the position of the substrate 1 was shifted due to thermal deformation caused by the difference in coefficient of thermal expansion between the cover 3 and the cover 3.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a substrate mounting structure for a position detection sensor, which reduces variations between individual sensors through assembly and reduces errors due to temperature changes. This should be the first issue.

A second object of the present invention is to provide a substrate mounting structure for a position detection sensor that can prevent displacement of the substrate due to temperature changes.

"Means and Effects for Solving the Problem" A substrate mounting structure for a position detection sensor according to the present invention for solving the first problem described above includes a substrate having a resistor surface, and a mounting structure for sliding the resistor surface on the substrate. A slider having a contact portion that changes the electrical resistance of the substrate, a case that slidably holds the slider, and a cover that closes the inside of the case, the slider having a contact portion that changes the electrical resistance of the substrate, and a cover that closes the inside of the case. In the substrate mounting structure for a position detection sensor that exhibits a corresponding resistance value, the substrate is attached to a case, and the mounting position thereof is located close to the mounting position of the slider and the case.

According to the above configuration, since both the board and the slider are attached to the case, variations in the relative positions of the board and the slider are only affected by variations in dimensions during molding of the case. , it is no longer affected by variations in the assembly position of the case and cover.

Furthermore, since the mounting position of the board and the case is located close to the mounting position of the slider and the case, the influence of dimensional changes in the case due to temperature changes can be reduced.

Further, since both the substrate and the slider expand and contract with the mounting portion on the case side as the reference position, errors due to temperature changes are caused only by the difference in coefficient of thermal expansion between the two.

Next, in the substrate mounting structure of the position detection sensor of the present invention for solving the second problem, the substrate is pressed against the case by a spring member, and the substrate and the spring member are provided on the substrate. They are characterized in that they are positioned relative to each other by an engaging hole provided in the spring member and a pawl that is provided in the spring member and engages with the engaging hole.

According to the above configuration, the board and the case are not joined to each other and can be expanded and contracted, so that generation of thermal stress due to a difference in coefficient of thermal expansion is prevented, and cracking of the board is prevented. Furthermore, since external impact is alleviated by the spring member, cracking of the board is prevented. The spring member and the substrate are positioned relative to each other and are prevented from shifting.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a sectional view showing the main parts of a position detection sensor according to an embodiment of the present invention, Figure 2 is a left side view with the cover removed, Figure 3 is a right side view, and Figure 4 is a board. It is a perspective view showing a spring member.

This position detection sensor consists of a substrate 1. Leaf spring 6. Slider 4.
Case 2. It is equipped with a cover 3, etc., and the mounting surface 2a is attached to a fixed member of the object to be detected (not shown) as a reference, and a moving member of the object to be detected (not shown) is brought into contact with the tip 43a of the operation bottle 43 to detect its position. It is something to do.

The case 2 is made of an insulating material such as synthetic resin, and the case 2 is made of an insulating material such as synthetic resin.
．． Leaf spring 6. Slider 4. and coil spring 5 to opening 2
A terminal 7 is installed from the b side, and a lead wire 71 is connected to the terminal 7. A grommet 73 for collecting the lead wires 71 is attached from the mounting surface 2a side. A bushing 21 is fixed to the case 2. As shown in FIG. 2, mounting fR2c is provided at two opposing locations in the case 2, and a stopper portion 2d is formed at the back of the mounting fR2c.

The substrate 1 is made of a brittle material such as ceramic, and its -
A resistor surface 1a is formed on the surface. Board 1 has mounting groove 2
Using C as a guide, it is mounted from the opening 2b side so that the end 1b abuts against the stopper 2d. As shown in FIG. 4, an engagement hole IC at 211I is bored in the substrate 1 near the end 1b.

The leaf spring 6 is bent into a substantially arcuate cross section, and has two pawls 6a raised at one end. The leaf spring 6 is attached to the case 2 together with the board 1, but at this time, the claw 6a engages with the engagement hole IC to prevent the leaf spring 6 from shifting with respect to the board 1. After being attached to the case 2, the outer diameter side of the arc-shaped cross section of the leaf spring 6 contacts the inner wall of the case 2, and elastically supports the board 1.

The slider 4 includes a slider 45. Brush 41. and an operation pin 43 are joined to form a single unit.

The slider 45 and the operation pin 43 are integrally molded. The operating pin 43 is movably fitted into the bushing 21, and the slider 45 is urged toward the bushing 21 by the coil spring 5. The brush 41 is made of an elastic conductive material, is fixed to the protruding portion 45a of the slider 45, and is bifurcated toward the contact portion 41a. The contact portion 41a moves together with the slider 4 and changes the resistance value of the substrate 1. The board 1 is a lug terminal 75. Connected to lead wire 71 by terminal 7, this lead wire 7
1, the output is taken out.

Each part is attached to the case 2, and the tongue piece 7a of the terminal 7
After the and lug terminal 75 are joined by welding or the like,
Cover 3 is attached. At this time, the inside of the case 2 is sealed by the O-ring 22 installed in the groove 2e provided in the opening 2b of the case 2.

"Operation" Next, the operation of the above configuration will be explained.

The object to be measured (not shown) is the tip 4 of the movable member operating bin 43.
3a and further approaches the sensor, the slider 45 moves toward the cover 3 while compressing the coil spring 5. The contact portion 41a of the brush 41 on the resistor surface 1a of the substrate 1 moves together with the slider 4, and
change the resistance value of

In the position detection sensor according to this embodiment, the substrate 1
and slider 4 are both assembled to the case 2 side independently of the cover, and errors due to positional variations no longer occur when assembling the case 2 and cover 3.

Furthermore, since the stopper portion 2d, which the substrate 1 contacts, and the end surface 21a of the bushing 21, which the slider 4 contacts, are close to each other, the case 2 is less susceptible to dimensional changes due to temperature changes.

The substrate 1 and the slider 45 of the slider 4 expand or contract in the same direction with respect to the stopper portion 2d or the end surface 21a of the bush 21 as a reference when the temperature changes. Therefore, the dimensional changes between the substrate 1 and the slider 45 are canceled out, and the error becomes a slight dimensional error due to the difference in thermal elongation between the substrate 1 and the slider 45.

The board 1 is elastically supported with respect to the case 2 by a leaf spring 6, and thermal stress is generated even if the dimensions of the board 1 and the case 2 differ due to differences in thermal expansion coefficients when the temperature changes. According to this embodiment, the substantially rectangular substrate 1 is provided in two places in the bag 711 facing the case 2.
12c, the area of the contact portion is increased and the impact load per area is reduced.

"Other Embodiments" The present invention is not limited to the details of the above embodiments. For example, as shown in FIGS. 5 and 6, the opening 2b side of the mounting groove 2C provided in the case 2 The protruding portion 2f may be provided in the protruding portion 2f.

This makes it difficult for the mounted board 1 to come into contact with the protrusion 2f and come off. Furthermore, by determining whether or not the end of the board 1 on the opening 2b side has passed through the protrusion 2f, it is possible to check whether the board 1 is correctly attached to the position where it contacts the stopper part 2d. It is effective as a means of detecting defective products when

"Effects of the Invention" As described above, in the substrate mounting structure of the position detection sensor of the present invention, the variation in the relative position between the substrate and the slider depends only on the molding error of the case, and the assembly of the cover with respect to the case Since it is not affected by the attachment position, the accuracy is improved and there is an effect that the accuracy of the assembly position of the cover can be made rough during manufacturing.

Furthermore, since the mounting position of the board and the case is located close to the mounting position of the slider and the case, the case is less susceptible to dimensional changes due to temperature changes. Since both the substrate and the slider expand or contract in one direction of the cover with the mounting part on the case side serving as the reference position, the error due to temperature changes is a small value due to the difference in thermal elongation of the two. There is.

In addition, in the substrate mounting structure of the position detection sensor according to the second invention, the substrate and the case are each expandable and contractible, preventing the generation of thermal stress and absorbing external shocks by the spring member. This has the effect of preventing the substrate from cracking.

Since the spring member and the board are positioned relative to each other, the spring member and the board can be attached by pushing only one of them when assembling the case.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a position detection sensor according to an embodiment of the present invention, FIG. 2 is a left side view of the position detection sensor, FIG. 3 is a right side view of the position detection sensor, and FIG. 4 is a board FIG. 5 is a sectional view showing a position detection sensor according to another embodiment of the present invention, FIG. 6 is a left side view thereof, and FIG. 7 is a conventional position detection sensor. FIG. 100. Substrate, la, , resistor surface, lc,...
Engagement hole, 201. Case, 411. Slider, 41
a. 8. Contact portion, 611. Leaf spring, 6a...claw. Figure 4 Figure 4

Claims (2)

[Claims] (1) A substrate having a resistor surface, a slider having a contact portion that slides on the resistor surface to change the electrical resistance of the substrate, a case that slidably holds the slider, and the case. In the substrate mounting structure of the position detection sensor, the substrate is attached to the case, and the mounting position is changed to the slider. A substrate mounting structure for a position detection sensor, characterized in that the position detection sensor is mounted close to the mounting position between the sensor and the case. (2) The board is pressed against the case by a spring member, and the board and spring member are connected to an engagement hole provided in the board,
and a pawl provided on the spring member that engages with the engagement hole,
2. A substrate mounting structure for a position detection sensor according to claim 1, wherein the two are positioned with respect to each other.