JPH023928Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to an electric actuator used for controlling the position of a damper or the like installed in a ventilation passage.

(b) Prior Art Conventionally, this type of actuator has a housing 1 with an output shaft worm gear 3 of a motor 2 installed at a predetermined position inside the housing 1, and a reduction gear 4 interposed therebetween, as shown in FIGS. 4 to 7. The output gear 5 is meshed with the output gear 5, and on one side of the output gear 5, there are three contacts of the same phase that slide in contact with energizing cam patterns 7a, 7b, and 7c of a predetermined circuit printed and wired on the printed circuit board 6. 8a, 8b, and 8c are running. Contact points 8a, 8 for energizing cam patterns 7a, 7b
The rotation angle of the actuator output shaft 11 fixed at the center of the output gear 5 is set by the position b. The output shaft 11 is linked to an air mixing damper 12 shown in FIG. 8, and the characteristics of the load and rotation angle of the damper 12 are usually such that the load becomes heavier on both sides of maximum cooling and maximum heating, as shown in FIG. This is to tighten the cushion material to completely close the damper 12. Here, the rotation angle is shown in terms of the output shaft of the actuator.

20 is a heater, 21 is a cooler, 22 is a blower, and 23 is a damper for switching between air inside and outside the vehicle.

The actuator operating angle at the damper opening/closing angle is within the angle range A-A' shown in Figure 9, but due to errors during assembly, the actuator operating angle at the damper opening/closing angle may deviate to B-B'. There are cases where this happens.

Therefore, as shown in Figure 10, the output shaft rotation angle is
When the sliding contact 8a or 8b remains conductive at the edge 13a, 13b, which is the critical point just before turning off the cam pattern 7a or 7b, at a point where the load becomes heavy as at B', the load torque is reduced. Since the output torque exceeds the output torque of the actuator, the output shaft cannot rotate any further, and the motor becomes locked. A large current flows through this contact point, and the contact resistance is large at that edge, causing heat generation. There is a risk that the grease applied to improve the wear resistance of the contacts may burn.

There is a very small chance that the energizing cam pattern edge and the output shaft constraint match as described above, but near the OFF position, arcing is likely to occur due to the heavy load as described above, and due to the heat generation and products of the arc, the contact point This was causing poor contact, etc.

(c) Problems to be solved by the invention The problem to be solved by the invention is that even if contact failure occurs due to contact heating and contact damage due to arcing, etc., in the conventional current-carrying cam pattern edge described above, the current can be passed without any problem. The aim is to obtain an electric actuator that can maintain its functions and operate normally.

(d) Means for Solving the Problems The present invention provides a means for solving the above problems, which includes: an electric motor, an output shaft that outputs output from the electric motor to the outside via a reduction gear, and an operation of the output shaft. An energizing cam pattern for power feeding that limits the stroke, a energizing cam pattern for forward rotation and an energizing cam pattern for reverse rotation each having an overall length slightly shorter than the overall length of the energizing cam pattern for power feeding, and each energizing cam at the same position in synchronization with the electric motor. An electric actuator having an operation stroke limiting switch formed by a sliding brush that slides on a pattern and is electrically integrated with the sliding brush that slides on the forward rotation energizing cam pattern and is electrically integrated with the sliding brush. an auxiliary forward rotation sliding brush provided at a position advanced in phase from the forward rotation sliding brush in the forward rotation movement direction; and an auxiliary forward rotation sliding brush that slides on the reverse rotation energizing cam pattern; An auxiliary reversing sliding brush provided at a position advanced in phase from the reversing sliding brush and each of the aforementioned sliding brushes are integrally and conductively connected.

(e) Effect Next, the operation of the present invention will be explained.

When the sliding brush has an abnormality such as poor contact with the energized main cam pattern edge during normal operation and becomes inoperable, the auxiliary brush is integrally conductively connected to the edge of the cam pattern at a position further in phase than the sliding brush in the direction of movement. The sliding brush continues to perform the function of the sliding brush.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3 of the drawings.

Forward rotation energizing cam pattern 9a, reverse energizing cam pattern 9b, and power supply cam pattern 9c of the predetermined circuit printed and wired on the printed circuit board 6, the same phase sliding brush 10a for forward rotation and sliding brush 10a for reverse rotation contacting and sliding against the cam pattern 9c for power supply. A moving brush 10b and a power feeding sliding brush 10c are provided, and the forward rotation sliding brush 10a and the reverse rotation sliding brush 10b are provided with an auxiliary forward rotation sliding brush 14a and an auxiliary forward rotation sliding brush 14a, respectively, at a position where the phase is advanced by α degrees in the moving direction. An auxiliary reversing sliding brush 14b is provided, and each of the sliding brushes 10a, 10b, 10c, 14a, 14
In b, a brush body 15 is fixed to the output gear 5, which is integrally and conductively connected at the body portion 10d.

In the drawings, parts indicated by the same reference numerals indicate equivalent and corresponding parts.

(g) Effect of the invention As is clear from the above explanation, the present invention has a forward rotation sliding brush and a reverse rotation sliding brush of the same phase that contact and slide against the energized main cam pattern, each having a phase in the direction of movement. Since the auxiliary forward rotation sliding brush and the auxiliary reverse rotation sliding brush are integrally conductively connected at the advanced position, the energized main cam pattern terminal end 1 is now connected.
3a, 13b are the main sliding brushes 10a, 1
When 0b remains stationary and becomes inoperable, each auxiliary sliding brush 14a, 14b is separated from the energized main cam pattern, so that the auxiliary sliding brush and its cam pattern compensate, and the auxiliary sliding brush also slides. The load on the damper is light near the off point of the auxiliary sliding brush, which is integrally conductively connected at a position where the phase is ahead of the brush in the direction of movement, and the actuator output shaft continues to rotate even after the motor power is turned off due to motor inertia. Therefore, it does not stop at the pattern edge and turns off at a high speed, so not only is it difficult for arcs to jump, but the auxiliary sliding brush does not generate heat at the contact point or generate carbide due to arcing, etc., so it can slide without hindering contact. It functions as a safety valve for the brush.

Further, when the sliding brush is functioning normally, the operating angle stroke is always determined by the position of the sliding brush, so the auxiliary sliding brush does not become an obstacle.

The present invention can not only be used to control the position of dampers in ventilation passages, but also widely applicable to electric actuators that drive retractable headlamps and the like.

[Brief explanation of the drawing]

Fig. 1 is an equivalent circuit diagram of an embodiment of the present invention, Fig. 2 is a pattern diagram of a printed circuit board, Fig. 3 is a front view showing the configuration of a brush body fixed to an output gear, and Fig. 4 is an equivalent circuit diagram of an embodiment of the present invention.
The figure is a schematic diagram showing the configuration of a conventional actuator, Figure 5 is an equivalent circuit diagram, Figure 6 is a side view of the main part showing the relationship between the output gear and the printed circuit board, and Figure 7 is a schematic diagram showing the configuration of a conventional actuator.
The figure is a plan view of the printed circuit board, Figure 8 is a schematic diagram of the air conditioning system, Figure 9 is a diagram of the damper load characteristics with respect to the output shaft rotation angle, and Figure 10 is the damper load diagram and the energization pattern immediately before turning off. FIG. 1... Housing, 2... Motor, 3... Worm gear, 4... Reduction gear, 5... Output gear,
6... Printed circuit board, 9a, 9b, 9c... Energizing cam pattern, 10a, 10b, 10c... Sliding brush, 10d... Body, 11... Actuator output shaft, 12... Air mixing damper, 13
a, 13b...edge (main contact), 14a, 14
b...Auxiliary sliding brush, 15...Brush body.

Claims (1)

[Scope of Claim for Utility Model Registration] An electric motor, an output shaft that takes output from the electric motor to the outside via a reducer, a current-carrying cam pattern for power feeding that limits the operating stroke of the output shaft, and the total length of the current-carrying cam pattern for power feeding. It is formed by a forward rotation current-carrying cam pattern and a reverse rotation current-carrying cam pattern, which have a slightly shorter overall length, and a sliding brush that slides on each current-carrying cam pattern in the same phase and in synchronization with the electric motor, and is electrically integrated. In an electric actuator having an operation stroke limiting switch, the electric actuator slides on the energized cam pattern for forward rotation and is provided at a position that is more advanced in phase than the sliding brush for forward rotation in the forward rotation movement direction of the sliding brush. an auxiliary forward rotation sliding brush; and an auxiliary reversal sliding brush that slides on the reversal energized cam pattern and is provided at a position that is more advanced in phase than the reversal sliding brush in the sliding brush reverse movement direction. and an electric actuator, wherein each of the sliding brushes is integrally and conductively connected.