JPH073268U - Worm wheel of motor with reduction gear - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a worm wheel for a motor with a reducer, which has reduced mechanical loss and improved motor starting characteristics, especially starting torque at low temperatures. [Structure] A worm wheel 1 of a motor with a reduction gear is provided with two types of ribs 1a and 1b for preventing fall and sliding contact, and the end surface of the sliding contact rib 1b has a wavy shape having three or more convex surfaces. With such a different shape, the contact area between the worm wheel 1 and the cover 2 becomes extremely small, and the friction loss can be reduced. Therefore, even when the viscosity of the lubricant such as grease applied to the sliding contact surface becomes large especially at low temperature, the influence thereof is small and the motor starting torque can be prevented from becoming small.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a worm wheel for a motor with a reducer that reduces mechanical loss such as friction loss of the reducer and improves the starting characteristics of the motor, especially the starting torque at low temperatures.

[0002]

[Prior art]

 Conventionally, in order to reduce mechanical loss such as friction loss of a motor with a reducer, there are some that apply a lubricant such as grease to friction points and use a material with a small friction coefficient.

A conventional motor with a speed reducer will be described below. FIG. 4 is a structural sectional view of a speed reducer portion of a conventional motor with a reducer. Reference numeral 1 is a worm wheel, 1c is a sliding contact rib which also functions to prevent falling, 2 is a cover, 3 is an output shaft, 4 is a bearing, 5 is an O-ring rubber, 6 is a sealant, 7 is a damper rubber, 8 is a C-ring, 9 Is a torque transmission plate, 10 is a worm gear, and 11 is a gear case.

A worm gear 10 is fixed to the tip of a motor shaft (not shown), and a worm wheel 1 arranged so as to be oriented in a direction of a rotation center axis perpendicular to the motor shaft is rotated, and a worm wheel 10 is passed through a torque transmission plate 9. The rotation is transmitted to the output shaft 3.

FIG. 3 is an exploded perspective view showing a bearing state of a worm wheel of a conventional motor with a reducer. The worm wheel 1 and the cover 2 are in direct contact with each other by the sliding contact rib 1c that also functions to prevent falling, and the rib portion having the same diameter as the outer diameter of the worm wheel is the entire sliding surface. The worm wheel is not firmly fixed to the shaft, so it is necessary to prevent it from tipping over. The sliding portion between the worm wheel 1 and the cover 2, particularly the rib portion 1c which is the sliding portion, is made of a material having a small friction coefficient, or the rib portion 1c is coated with grease. The lubricating action of this grease reduces mechanical loss such as friction loss and improves the starting characteristics of the motor.

[0006]

[Problems to be solved by the device]

 However, in the above-mentioned conventional configuration, in order to reduce the mechanical loss of the motor with a reducer, for example, a lubricant such as grease is applied to a friction portion or a material having a small friction coefficient is used. At low temperatures, the viscosity of lubricants such as grease increased, and the larger the sliding contact area, the greater the mechanical loss, and the starting characteristics of the motor, that is, the starting torque, decreased, and the motor could not be started. .

Further, even if a material having a small friction coefficient is used as a part material used in a place where friction occurs without using a lubricant such as grease, the friction coefficient changes especially at low temperatures and the self-lubricating effect is suppressed. In some cases, mechanical loss such as friction loss cannot be reduced.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a worm wheel that can suppress an increase in friction loss of a speed reducer particularly at low temperatures.

[0009]

[Means for Solving the Problems]

 In order to achieve this purpose, the worm wheel of the motor with reduction gear of the present invention is equipped with two types of ribs for fall prevention and sliding contact, and the rib radius for sliding contact is set to be larger than the rib radius for fall prevention. It is configured to be small, and the end faces of the sliding contact ribs are integrally formed in a different shape such as a corrugated shape having three or more convex surfaces to reduce the contact area.

[0010]

[Action]

 With this structure, the sliding contact area between the end surface of the worm wheel and the cover is reduced, and even if the viscosity of the lubricant such as grease and the friction coefficient of the sliding part increase, especially at low temperatures, the effect is small and mechanical. It is possible to suppress an increase in loss. Therefore, it is possible to prevent the starting characteristic of the motor, that is, the starting torque, from being lowered, and especially to prevent the motor from being unable to start at a low temperature. In addition, the ribs for preventing fall can ensure sufficient reliability as in the past.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a sectional structure of a speed reducer portion of a motor with a speed reducer according to an embodiment of the present invention. A worm gear 10 provided at the tip of a motor shaft (not shown) rotates, torque is transmitted to a worm wheel 1 arranged so that the center axis of rotation is at right angles to the motor shaft, and a torque transmission plate is provided to the worm wheel 1. The output shaft 3 which is in contact with the shaft 9 and is axially supported by the bearing 4 and sealed by the O-ring rubber 5 is connected to the torque transmission plate 9. The parts are inserted in the gear case 11 and covered with the cover 2.

FIG. 1 is an exploded perspective view showing a bearing state of a worm wheel of a motor with a speed reducer according to an embodiment of the present invention.

As shown in FIG. 1, two types of ribs, a rib 1a for preventing fall and a rib 1b for sliding contact, are provided, and the rib 1b for sliding contact is provided in the vicinity of the bearing of the worm wheel where the sliding contact area can be reduced. It is installed, that is, the radius of the sliding contact rib 1b is set smaller than the radius of the fall prevention rib 1a, and the end surface shape of the sliding contact rib 1b is a different shape such as a wavy shape having three or more convex surfaces. By doing so, the sliding contact point between the worm wheel 1 and the cover 2 is normally only the end face of the sliding contact rib 1b except when the worm wheel falls.

Therefore, the contact area becomes extremely smaller than that of the conventional one, and mechanical loss such as friction loss can be reduced while maintaining the conventional reliability. Even if the viscosity of the lubricant such as grease applied to the sliding contact surface becomes large at low temperature, the sliding contact area is much smaller than before, so the effect is small, and the friction loss and other mechanical It is possible to suppress an increase in physical loss.

FIG. 5 shows a representative characteristic of the change in the starting torque depending on the ambient temperature of the motor with a reducer in the embodiment of the present invention in comparison with the conventional motor with a reducer. From FIG. 5, it is shown that the embodiment of the present invention has an effect of suppressing an increase in mechanical loss particularly at lower temperatures.

[0016]

[Effect of device]

 As is apparent from the above embodiment, in the motor with reduction gear according to the present invention, the end face of the rib for sliding contact provided on the output shaft side of the worm wheel is integrally molded into a different shape such as a corrugated shape that reduces the contact area. As a result, the sliding contact area with the cover can be reduced, and the friction loss of the reducer can be reduced, which has the effect of suppressing the increase in mechanical loss particularly at low temperatures.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a bearing state of a worm wheel of a motor with a speed reducer according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a speed reducer of a motor with a speed reducer according to the present invention.

FIG. 3 is an exploded perspective view showing a bearing state of a worm wheel of a conventional reduction gear motor.

FIG. 4 is a cross-sectional view showing the structure of a conventional speed reducer motor.

FIG. 5 is a diagram showing the relationship between the motor starting torque and the ambient temperature in the case of the embodiment of the present invention and the conventional example.

[Explanation of symbols]

 1 Worm wheel 1a Fall prevention rib 1b Sliding contact rib 1c Fall prevention and sliding contact rib 2 Cover 3 Output shaft 4 Bearing 9 Torque transmission plate 10 Worm screw 11 Gear case

Claims (1)

[Scope of utility model registration request] 1. A reduction gear motor comprising: a worm gear formed at a tip of a motor shaft; and a worm wheel arranged so as to be in a direction of a rotation center axis perpendicular to the shaft. A worm wheel for a motor with a speed reducer, comprising: a sliding contact rib; and an end surface of the sliding contact rib integrally formed into a corrugated shape having three or more convex surfaces.