JPH0620087Y2 - Power transmission device for throttle valve opening sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a power transmission device for a throttle valve opening sensor, and particularly to a rotary shaft (driven shaft) of a movable brush sliding on a resistance layer. Further, the present invention relates to an angle transmission link for transmitting a rotation amount according to a throttle valve opening, that is, a power transmission device of a throttle valve opening sensor.

(Prior Art) FIG. 3 is a partial sectional view showing an example of a conventional throttle valve opening sensor and angle transmission link structure. A bearing (metal) 12 is embedded and molded in the center axis of a resin case body 10.

A rotating shaft 14 made of resin is also rotatably fitted in the bearing 12, and the arm portion 1 is formed at one end of the rotating shaft 14.
A sliding brush 16 is fixed to 4A, and a lever 18 is fixed to the other end.

The drive shaft 15 rotates by a predetermined angle according to a change in the position or the opening angle of a throttle valve (not shown) of the internal combustion engine. The drive shaft 15 is arranged coaxially with the rotary shaft 14, and a rotary disc 17 is fixed to the end thereof.

Further, the rotary disc 17 is provided with a position eccentric from the center of rotation thereof, that is, a position displaced from the central axis of the drive shaft 15,
Driven tongue 1 by any suitable means such as bending or planting
9 is formed. The drive tongue piece 19 is provided so that its extending direction, that is, the length direction thereof is parallel to the drive shaft 15, and the drive tongue piece 19 engages with the lever 18 in a perpendicular state.

Therefore, when the throttle valve is opened and closed, the drive shaft 15
Rotates according to the opening and closing, and the drive tongue 19 rotates about the drive shaft 15. As a result, the lever 18 that engages with the drive tongue piece 19 is biased, and the rotary shaft 14 on the sensor side to which the lever 18 is fixed rotates. The sliding brush 16 rotates on a predetermined circumference according to the rotation of the rotary shaft 14.

A resistance substrate 20 is arranged so as to face one end surface of the rotary shaft 14 and in parallel with a rotation trajectory surface of the sliding brush 16. A resistance layer 22 is formed on a surface of the resistance substrate 20 that faces a rotation trajectory surface of the sliding brush 16. The resistance substrate 20 is pressed and fixed to the case body 10 by the back cover 26 via the O-ring 24.

A spring washer 28 is mounted between the arm portion 14A and the case body 10 (or the bearing 12), while the lever 1
A coil-shaped return spring 30 which also serves as a compression spring is mounted between the case 8 and the case body 10.

One end of the return spring 30 is locked to the boss 38, and the other end is locked to an appropriate portion (not shown) of the lever 18.

Here, since the strength of the spring washer 28 is selected to be larger than the axial elastic force of the return spring 30, the axial elastic force acts rightward in FIG. The inner surface of the lever 18 fixed to the other end is held in contact with the end surface of the bearing 12.

A space is left inside the lever 18 between the rotary shaft 14 and the bearing 12, and an O-ring 32 for sealing is attached thereto. One end of the resistance layer 22 is drawn out to the outside via a lead wire 34 and an external lead 36 soldered 37 thereto.

The O-ring 32 serves to prevent harmful gas, moisture, foreign matter, dust, etc. from entering the throttle valve opening sensor through the gap between the bearing 12 and the rotary shaft 14. The resistance layer 22 is formed by the two O-rings 24 and 32.
And the space in which the sliding brush 16 is located is properly sealed from the external environment.

At the time of power, the lever 18 is rotated via the power transmission mechanism including the drive shaft 15, the rotating disk 17 and the drive tongue 19 according to the position or the opening angle of the throttle valve of the internal combustion engine. Accordingly, the sliding brush 16 slides on the resistance layer 22 as in the case of a normal potentiometer or a variable resistance.

As a result, a voltage corresponding to the position or opening angle of the throttle valve is generated between the lead wire 34 and the sliding brush 16. This voltage is used as a throttle valve opening signal for controlling the internal combustion engine or the like.

It should be noted that, in the driven side lever 18 and the driving side driving tongue piece 19 of the power transmission mechanism, the driving side and the driven side are replaced with each other. That is, the drive tongue piece 19
Is formed on the lever 18 on the driven side to form a driven tongue piece, and this driven tongue piece is engaged with the rotary disc 17 on the driving side.

In either case, one of the driving side and the driven side is an engaging pin extending perpendicularly to the rotation center axis thereof, that is, the driving tongue piece 19 of the lever 18 in the example shown in FIG.
Has a portion that comes into contact with the other, and the other has an engaging tongue in a position parallel to and eccentric to the rotation center axis thereof, that is, the one corresponding to the driving tongue 19 in the example shown in FIG. ing.

(Problems to be Solved by the Invention) The conventional techniques described above have the following problems.

(1) Engaging tongue on the driving side of the power transmission mechanism, that is, driving tongue 1
9 and the engaging pin on the driven side, that is, the portion of the lever 18 that comes into contact with the driving tongue piece 19 are both formed of a cylindrical member, they are engaged in an orthogonal state, and therefore, they are mutually pointed. You will come into contact.

The contact state between the lever 18 and the drive tongue piece 19 will be described with reference to the drawings. FIG. 5 shows the drive side of the power transmission mechanism,
FIG. 6 is a perspective view showing an engaged state with a driven side, that is, a sensor side, and FIG. 6 is a view of the driven side, that is, the sensor side in FIG. 5, viewed from the driving side. In FIGS. 5 and 6, the portion 1 of the lever 18 that engages with the drive tongue piece 19
8B has a cylindrical shape, and the drive tongue piece 19 also has a cylindrical shape. When the members engaging in this manner are cylindrical, the lever 18
The contact portion f between the portion 18B and the driving tongue piece 19 is in a point contact state in which the contact area is very small.

When the members are engaged with each other by point contact, the contact pressure is higher because the contact area is smaller than when they are engaged with each other in other contact states such as line contact and surface contact. If the contact pressure is high,
Wear of both members is large at the engaging portion between the driving side and the driven side. If the ideal engagement state is obtained, the contact position between the driving side and the driven side is constant in the example shown in FIG. 3, and therefore wear does not occur even if the contact pressure is high.

However, from the viewpoint of productivity, it is usual that the shafts on the driving side and the driven side, which are opposed to each other, are provided with a permissible error range in the mutual displacement and the mounting angle. When the axes are displaced within such a tolerance range, the contact positions are always moved according to the rotation of the rotary shaft 14 and the drive shaft 15, so that they slide under a high contact pressure. Wear of parts occurs.

For example, when the rotating shaft 14 and the drive shaft 15 are parallel to each other and their centers are displaced from each other within the allowable error range, the lever 18 is rotated as the shafts 14 and 15 rotate.
18B and the driving tongue piece 19 are indicated by arrow X in FIG.
Slide in the direction of. Further, the rotary shaft 14 and the drive shaft 15
However, if they are not parallel to each other within the allowable error range, they slide not only in the direction of the arrow X but also in the direction of the rotary shaft 14 and the drive shaft 15 (direction of arrow mark Y in FIG. 6). When the driving tongue piece 19 and the lever 18 are worn, they do not slide smoothly in the directions X and Y, and the driven side cannot accurately follow the movement of the driving side.

The rotating shaft 14 is rotated in the returning direction (the arrow R direction in FIG. 5) by the return spring 30 (FIG. 3) so as to follow the rotation of the driving shaft 15 during the valve closing operation. In order to easily rotate the drive shaft 15 with a small force when the valve is opened, and considering the strength of the entire sensor in consideration of the impact at the time of returning, the return spring 30 cannot be made too strong. .

For the above reason, the return spring 30 cannot be strengthened, and therefore when the contact surface becomes rough due to wear and does not slide smoothly, the rotary shaft 1 is rotated with respect to the rotation of the drive shaft 15 in the return direction.
The rotation of 4 cannot follow accurately. Especially the return spring 3
As 0 expands, the spring force becomes weaker, so the drive shaft 15
When the valve is completely returned to the closed position, the strength of the return spring 30 cannot overcome the frictional force of the rough contact surface, and the rotary shaft 14 may not be completely returned.

If the rotary shaft 14 does not return to the predetermined position when the valve is closed, the throttle valve is actually closed, but the output signal of the sensor does not represent the closed state. In the vicinity of the closed state of the throttle valve, that is, during idling operation or low speed operation, it is necessary to accurately detect the opening degree of the throttle valve and perform particularly accurate control,
There is a strong demand for eliminating the above-mentioned phenomenon in which the rotary shaft 14 does not follow the drive shaft 15 near the valve closed position.

(2) If the driving side and driven side that have cylindrical pins are to be integrally formed by molding or punching, the cost will increase due to the cost of manufacturing a complicated mold and the increase in man-hours. Therefore, the actual production is difficult. Therefore, a separate pin is often press-fitted into the shaft member to form the driving side and the driven side, but even in this case, there is a problem that the cost becomes high. Not only is the drive tongue 19 fixed vertically to the rotating disc 17 (parallel to the drive shaft 15),
Since it is difficult to fix the portion of the lever 18 (engagement pin) that engages with the drive tongue piece 19 to the lever 18 so as to be perpendicular to the rotation shaft 14, it is possible to move from the rotation center to the engagement portion. It is difficult to control the arm length (working distance) of the arm as designed, which easily causes an error.

(3) Even when both the drive tongue piece 19 and the engagement pin of the lever 18 are plate-shaped bodies, the engagement state of one of the plate-shaped bodies is different from each other due to a mounting error represented by the mounting angle of these. The corner comes into point contact with the other surface,
The same problem as (1) will occur.

In order to solve the above-mentioned problems, the present invention increases the contact area between the driving side and the driven side in the engaging portion to reduce the wear of the engaging portion, and fixes the engaging pin to the rotating shaft. The object is to be able to be integrally formed with the mounting member to be mounted.

(Means and Actions for Solving Problems) In order to solve the above problems, the present invention provides one of a driving side and a driven side, which extends perpendicularly to a central axis of rotation thereof. A U-shaped engaging pin (having a substantially semi-circular or semi-elliptical cross section) is provided, and an engaging tongue composed of a flat plate is provided on the other side, and the flat plate is eccentric from the rotation center axis, In addition, it is characterized in that it is configured to incline at a predetermined angle with respect to the rotation center axis and to be in line contact with the engagement pin.

Due to the structure of the driving side and the driven side as described above, even if there is some error in the shape and mounting angle of the engaging pin, the line contact state between the two is maintained, preventing an excessive increase in contact pressure. The action of doing can be produced.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing a main part structure of an embodiment of the present invention, FIG. 2 is a side view thereof, and FIG. 4 is a perspective view. In these figures, the same reference numerals as those in FIG. 3 represent the same or equivalent parts.

The lever 18 fixed to the tip of the rotary shaft 14 is provided with an engagement pin 18A so as to vertically project from the rotation center shaft 11.
Is formed, and its cross section is formed in a substantially U shape such as a substantially semicircular shape or a semielliptical shape. Therefore, the lever 18 and the engaging pin 18A can be integrally manufactured by punching or molding, and it is easy to accurately form an angle (perpendicular) with respect to the rotation center axis 11.

A flat plate-shaped engaging tongue piece 19 </ b> A is formed on the rotary disc 17 fixed to the tip of the drive shaft 15. The engaging tongue piece 19A
Can be manufactured integrally with the rotary disk 17 by bending or the like. Here, the engaging tongue piece 19A is configured such that the surface in contact with the engaging pin 18A does not coincide with the surface including the rotation center axis 11 and forms a predetermined angle α with respect to this, as shown in the figure. .

The rotating shaft 14 is given a force in the direction to push back the engaging tongue 19A by a suitable returning means similar to the return spring 30 shown in FIG. 3, while the drive shaft 15 responds to the opening angle of the throttle valve. Rotate. Therefore, the stop position of the rotary shaft 14 depends on the opening angle of the throttle valve.

In the present embodiment, even when the drive shaft 15 and the driven shaft, that is, the rotary shaft 14 are deviated from each other or the mounting angles are different from each other, they can be brought into line contact with each other, and the lever 18 and the engagement pin 18A can be connected. It has been made easier to mold together. That is, when the engagement pin 18A is formed in a cylindrical shape, it is difficult to remove the lever 18 and the engagement pin 18A from one direction. Therefore, the engagement pin 18A has a substantially U-shaped cross section and is integrally molded. It has been made easier to remove the mold.

When the cross-sectional shape of the substantially U-shape that allows easy die-cutting is used, the following consideration is given to improve the contact state between the engaging tongue piece 19A and the engaging pin 18A.

FIG. 7 is an enlarged view showing an engaged state of the engaging tongue piece 19A and the engaging pin 18A. As shown in the figure, the engaging tongue 1
When 9A is made orthogonal to the engaging pin 18A, the side surface of the engaging tongue piece 19A comes into contact with the ridge portion 18C of the engaging pin 18A on the rotary shaft 14 side, so even though it is a line contact, the contact is made in an extremely narrow area. Come to do. In particular, it is remarkable when the forming angle of the engaging tongue piece 19A is deviated as shown by the dotted line.

Therefore, in this embodiment, the engaging tongue piece 19A is the engaging pin 1
8A is a plate-shaped body that can have a large contact area, and the engaging tongue piece 19A forms an angle α with the rotation center axis 11 (FIG. 1)
Have. As a result, the engagement tongue piece 19A abuts the side surface of the engagement pin 18A having a substantially U-shaped gently curved surface, that is, the partial cylindrical portion in a line contact state in a relatively large area.

This will be described with reference to FIG. In the figure, even if the angle α of the engaging tongue 19A varies from the state shown by the solid line to the state shown by the dotted line, the engaging tongue 19A engages with the engaging tongue 19A. With the pin 18A, the contact state of the engagement pin 18A with the substantially U-shaped gentle curved surface can be maintained.

That is, since the angle α of the engaging tongue piece 19A is given,
Even when the molding accuracy of the engaging tongue piece 19A is low, that is, when an error occurs in the angle α, the engaging tongue piece 19A and the engaging pin 18A can always maintain the line contact state in a relatively large area.

In the above description, the case where an error occurs in the angle α has been described. This is because the lever 18 and the rotating disc 17 are
It goes without saying that the same applies to the case where there is an attachment error with respect to the rotary shaft 14 or the drive shaft 15 in that the relative relationship between the engagement pin 18A and the engagement tongue piece 19A changes.

As described above, according to the present invention, the surface of the plate-like engaging tongue piece 19A and the substantially U-shaped bent portion of the engaging pin 19A having a substantially U-shaped cross section, that is, the partial cylindrical portion are engaged in a line contact state. Be combined. Therefore, even if there is an error in the mechanical structure or attachment of the rotating disk 17 or the lever 18 itself, the engagement state between the engagement tongue piece 19A and the engagement pin 18A can be maintained in the line contact state. As a result, the contact pressure can be reduced as compared with the case of a point contact having a small contact area, so that the wear caused by sliding is reduced. As a result, they can smoothly engage with each other, and the drive shaft 1
5, the followability of the rotary shaft 14 to the movement of No. 5 is improved, and as described above, the rotary shaft 14 is not completely returned to the predetermined position, and the rotary shaft 14 accurately follows the motion of the drive shaft 15. , The measurement error can be reduced.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the following effects are achieved.

(1) The engaging pin has a semicircular or semi-elliptical cross section,
Since it has a substantially U-shape, when a member to be fixed to the rotary shaft 14, that is, the lever 18 and the engaging pin are integrally processed, a mold for (for example, punching, molding) can be easily manufactured. It becomes easy to process with a small number of steps. That is, when forming a substantially U-shaped pin on the disk member, the molded product can be die-cut in one direction, whereas when forming a columnar pin on the disk member, Since it is not possible to perform die cutting in one direction, a divided die must be used, which leads to an increase in die manufacturing cost and man-hours. According to the present invention, such an increase in manufacturing cost and man-hours can be suppressed.

Further, the integral processing makes it possible to more accurately maintain the right angle (perpendicular) with respect to the rotation center axis of the engagement pin as compared with the case where the separate engagement pin 18A is erected on the lever 18. .

That is, the problem described in the second item of (Problems to be solved by the device) can be solved.

(2) The engaging surface of the engaging tongue piece with respect to the central axis of rotation so that the engaging tongue piece contacts the side surface of the engaging pin having a substantially U-shaped cross section in the widest possible area. And tilted at the planned angle. Therefore, even if there is a mounting error or machining error on the driving side and the driven side within the allowable range, the engagement part between the driving side and the driven side can always be maintained in a line contact state with a large contact area. The contact pressure of each other can be reduced. As a result, the degree of wear of the engagement portion is reduced, and highly accurate operation due to the smooth engagement state can be maintained for a long period of time.

That is, the problems described in the first and third items of (Problems to be solved by the device) can be solved.

[Brief description of drawings]

FIG. 1 is a front view showing the configuration of the essential parts of an embodiment of the present invention, FIG. 2 is a side view thereof, and FIG. 4 is a perspective view thereof. Further, FIG. 3 is a partial cross-sectional view showing an example of a conventional power transmission device for a throttle valve opening sensor, FIG. 5 is a perspective view of a main part of a conventional device, FIG. 6 is its front view, FIG. FIG. 8 is a view showing a contact state of the engagement pin and the engagement tongue piece. 10 ... Case main body, 12 ... Bearing, 14 ... Rotating shaft, 15 ...
Drive shaft, 16 ... Sliding brush, 17 ... Rotating disk, 18 ... Lever, 18A ... Engaging pin, 19 ... Driving tongue, 19A ... Engaging tongue, 20 ... Resistive substrate, 22 ... Resistive layer, 26 ... Case back,
28 ... Spring washer, 30 ... Return spring, 38
... Boss, 40 ... Seal member, 44 ... Sealant,

Claims (2)

[Scope of utility model registration request] 1. A bearing fixedly supported inside a case body, a rotary shaft rotatably fitted in the bearing, and fixed to one end of the rotary shaft, the rotary shaft being rotated. A sliding brush that moves on a predetermined locus, a resistance substrate that faces the movement locus of the sliding brush on its surface, and is fixed to the case body; A driven member fixed to the other end, a drive shaft arranged so as to have the same rotation center shaft as the rotation shaft, and rotated in response to a change in the opening degree of the throttle valve of the internal combustion engine; A power transmission device for a throttle valve opening sensor having a drive member fixed to the tip so as to engage with the driven member, and a return spring that biases the driven member toward the driving member, Either one of the driving member and the driven member is Has a substantially U-shaped cross section, and is an engagement pin that projects perpendicularly from the rotation center axis, and the other is eccentric by a predetermined distance from the rotation center axis and at a predetermined angle with respect to the rotation center axis. The power of the throttle valve opening sensor is an inclined plate-shaped engaging tongue, and the engaging pin is in contact with the engaging tongue on the side of the substantially U-shaped bent portion. Transmission device. 2. The power transmission device for a throttle valve opening sensor according to claim 1, wherein the plate-shaped engaging tongue is a flat plate.