JPH0343490Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a backgap gear device that reduces meshing noise by eliminating the backgap between gears to be meshed, and is applicable to various types of gears equipped with gears. It can be widely used in many devices.

[Conventional technology]

This type of backgap gear device consists of two gear elements with the same tooth profile and number of teeth, and these gear elements are elastically biased by a spring in mutually opposing rotational directions to maintain backlash with the other gear. They are starting to mesh together without any problems.

Various types of springs are known as springs for rotationally biasing the main and sub gears constituting both gear elements. -158349 Publication Figure 1) Torsion coil spring (Utility Model No. 158349-
Publication No. 160351), C-shaped round steel spring (Publication No. 48-
34438 Publication Figure 1, Utility Model Publication No. 1988-158349 Figure 3), hairpin springs (Utility Model Publication No. 48-34438 Figures 3 and 4, Utility Model Publication No. 48-2947 Publication No. 4)
), etc.

It is also known to use a C-clip type spring (also called a circlip, retaining ring, or snap ring depending on the application), and the present invention relates to a type of spring using this C-clip type spring.

In a device equipped with such a C-clip type spring, a round hole is provided at each end of the spring, and pins are inserted into each of these round holes to connect one end of the spring to the main gear and the other end to the sub gear. Concatenated. This model had the disadvantage that the assembly work was troublesome because the round hole had to be aligned with the pin. This is because fitting the main gear pin into the round hole of the C-clip spring is easy because you can see the pin and the round hole, but it is also easy to fit the sub-gear pin into the other round hole of the C-clip spring. This is because the matching work cannot be visually observed and must be done by hand. Therefore, in order to eliminate such drawbacks of the prior art, the applicant of the present application filed a U.S. Pat.
In No. 86061, we proposed a backless gear device with a structure that allows easy assembly. According to this, two pins are erected on one side of the gear element, for example, on one end surface of the main gear, so that the spring can be easily fixed to the main gear using holes formed at both ends of the C-clip spring. . One hole of the C-clip-shaped spring is an elongated hole larger than the size of the pin, so that the spring can be deformed when an external force is applied. The end face of the sub gear is recessed with a roughly C-shaped groove for the spring to fit into. Therefore, if the sub gear is simply stacked on the main gear, the spring fits into the groove of the sub gear, and the end of this groove When the spring comes into contact with the movable end of the spring, the elastic biasing force of the spring is obtained.

[Problem that the invention attempts to solve]

However, although the above-mentioned backless gear device can achieve the purpose of facilitating assembly work, it is relatively troublesome to process the C-shaped curved groove recessed in the end face of the sub gear (or main gear). There is a problem. Such curved grooves are generally formed by milling, but since the width of the curved grooves is very small, the machining operation is relatively troublesome.

The object of the present invention is to realize a backless gear device that is easy to manufacture and assemble by using a dowel pin instead of such a groove.

[Means for solving problems]

In order to achieve the above object, the backless gear device according to the present invention has two gears having the same tooth profile and the same number of teeth.
It consists of a gear element and a C-clip spring, two pins are erected on one end surface of one gear element, and a hole is provided at each end of the C-clip spring. are formed to engage respective pins and holes to attach the C-clip spring to the one gear element, and at least one of the holes at each end of the C-clip spring is formed with The C-clip-shaped spring is larger than the size of the engaging pin and can be deformed after being attached to the one gear element, and the C-clip-shaped spring is attached to one end surface of the other gear element. A knock pin is provided upright to fit into the third hole formed in the second hole.
When these gear elements are coaxially combined with the spring in between and their end faces facing each other, both gear elements can be slid relative to each other and rotated via the spring by fitting the third hole and the knock pin. is elastically connected to the

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail.

FIG. 1 shows a backless gear device 1 according to the present invention, which consists of a first gear element (main gear) 2, a second gear element (sub gear) 3, and a C-clip-shaped spring 4. This configuration forms one gear (scissor gear) that can mesh with any mating gear 30 as shown in FIG. The outer peripheries of the main gear 2 and sub gear 3 are provided with teeth 5 and 5, respectively, like a normal spur gear, for example.
6 are formed, and the tooth profile and number of teeth of these teeth 5 and 6 are mutually the same.

A cylindrical boss 7 is formed in the center of the main gear 2, and the inner diameter hole of the boss 7 allows the gear device 1 to be attached to an arbitrary shaft (for example, a camshaft 50). The inner diameter hole 8 of the sub-gear 3 is fitted into the outer circumferential portion of the boss 7, so that the main gear 2 and the sub-gear 3 can be rotatably combined with each other on the same axis. An annular groove 9 for a snap spring (not shown) is formed near the outer peripheral tip of the boss 7, and the sub gear 3 is regulated in the axial direction with respect to the main gear 2.

End face 10 of sub gear 3 facing main gear 2
Two pins 11 and 12 are set up on the top, and one C
Since holes 13 and 14 are formed at each end of the clip-shaped spring 4, the C-clip-shaped spring 4 is attached to the sub gear 3 by engaging the pin 11 with the hole 13 and the pin 12 with the hole 14, respectively. be able to.

In this embodiment, the positions of the pins 11 and 12 are such that the C-clip-shaped spring 4 is arranged approximately concentrically around the boss 7, and the C-clip-shaped spring 4 is inserted into the pins 11 and 12 with the spring 4 pushed out. It is established that it can be done. In this embodiment, the holes 13 and 14 of the C-clip spring 4 are both elongated holes that extend along the longitudinal direction of the spring 4 with respect to the diameters of the pins 11 and 12, but as will be described later, at least one It is sufficient if only the holes in are long holes. As a result, when the spring 4 is attached to the sub gear 3, as shown in FIG.
The inner ends 13a and 14a of 3 and 14 are connected to the pin 1, respectively.
1 and 12. However, if a counterclockwise external force is applied to the C-clip spring 4 as shown by arrow F, the spring 4 will move through the elongated hole 13 and the pin 1.
At this time, the other end of the spring 4 is fixed to the sub-gear 3 by engagement with the pin 12 and the hole 14. That is, in this sense, the hole 14 does not have to be an elongated hole, but may be a round hole having the same diameter as the pin 12. Conversely, pin 1
If the first side is considered fixed, the hole 13 may be a round hole into which the pin 11 is fitted. The aforementioned deformation of the spring 4 thus provides a reaction force to that external force. This reaction force elastically biases the main gear 2.

A knock pin 17 is provided on one end surface 16 of the main gear 2.
will be planted.

A third hole 18 corresponding to the dowel pin 17 is formed in the spring 4 . Preferably, a hole 19 identical to the hole 18 is formed at a symmetrical position, but this is a request for convenience of assembly so that the spring 4 can be attached either front or back. Basically, one hole 18 corresponding to the pin 17 is sufficient. The pin 17 is for connecting the main gear 2 and the sub-gear 3 when they are superimposed on each other via the spring 4. That is, main gear 2
pin 17, hole 18, spring 4, hole 14, pin 12
It is connected to the sub gear 3 via. hole 18 or 1
9 has an inner diameter larger than the diameter of the knock pin 17.

The gear device according to the present invention is assembled as follows.

The main gear 2 is assembled to a camshaft 50. The sub gear 3 has two notching pins 11 and 12 that are driven into it before being combined with the main gear 2.
Set the spring 4 so that it is pulled against the In other words, when the long holes 13 and 14 at both ends of the spring 4 are passed through the knock pins 11 and 12, the gap between the C-shaped springs is opened, and a so-called scissor gear scissoring force is generated.

The sub gear 3 with the spring 4 temporarily set in this way is assembled to the main gear 2 by passing the nog pin 17 of the main gear 2 through the hole 18 or 19 of the spring 4.

This state is shown in FIGS. 4 and 5. 4 and 5 the pin 17 is free within the hole 18. In FIGS.

The scissor gear, which is composed of the two gears 2 and 3 and the spring 4 that connects them, is connected to the mating gear 3.
0 (FIG. 7), the pin 17 contacts one side of the inner wall of the hole 18 as shown in FIG. The pins 11 or 12 are elastically pushed apart by the teeth of the mating gear 30 in response to the force, and the pins 11 or 12 are pushed into the elongated hole 1.
3 or 14 and becomes free. This state is shown in FIGS. 6 and 7. That is, the spring 4 is brought from the position shown in FIG. 4 to the position shown in FIG. 6 by the pin 17 when the gears are engaged. This will be explained in detail as follows. In the position shown in FIG. 4, where the main gear 2 is not meshed with the mating gear 30, it is free from the C-clip spring 4, but its play (pin 1
7 and the hole 18) is smaller than the distance between each tooth 5 or 6. Therefore, when this gear device 1 is assembled so as to mesh with the mating gear 30, the mating gear 30 will be inserted between the teeth 5 of the main gear 2 and the teeth 6 of the sub gear 3, as shown in FIG. and sub gear 3 when the assembly is completed.
receives a force F from the mating gear 30, thus shown in FIG. The pin 17 abuts against the end of the hole 18 of the C-clip spring 4 to expand the spring 4, causing the spring 4 to expand.
It will receive an elastic biasing force from. This elastic biasing force has a component in the opposite direction to the force F in FIG. 7, so there is always no backlash between the gear 30 and the gear (device) 1, and meshing noise is reduced. In this specification, the term "C-clip-shaped spring hole" includes a hole formed by a hook or the like that is generally used for engaging such a spring with a pin.

As described above, by assembling the scissor gear with the teeth of the sub gear and the main gear slightly misaligned with the mating gear, the necessary spring force for the operating state can be obtained from the temporarily set position. The margin up to this position is determined by the amount of tooth misalignment between the sub gear and the main gear at the temporary set position. However, this margin cannot be increased from the viewpoint of accuracy and number of joint parts. Therefore, for example, pin 12 (or 17) is
As shown in 2', the elongated hole 14 or round hole 1 is worn out.
If the contact position with 8 shifts, the above-mentioned margin becomes zero, and as a result, the spring force is received by the presetting knob pin 11 in the elongated hole 13, and the spring force becomes zero and there is a possibility that the scissor gear will lose its function. There is.

Therefore, the pin 12 on which the load acts during use is
For the pins 11 and 17, a material with excellent wear resistance and surface treatment is selected, but for the pin 11, a material that wears out aggressively enough to withstand the static load during presetting is selected. This is done in consideration of the fact that the knock pin 11 is of no use when it is used only for temporary setting, as is clear from FIG. As a result, even if pins 12 or 17 wear out, for example, and reach a region where the scissor gear would otherwise lose its function, the scissor gear function can be maintained if pin 11 wears out more aggressively (No. 9 figure).

Examples of the material of the pin 11 that causes wear as described above include S material, A material, which is not subjected to heat treatment,
Examples include copper, total copper, and resin.

Furthermore, if the diameters of the pins 11 and 12 and the sizes of the elongated holes 13 and 14 are made different from each other, incorrect assembly can be prevented.

[Effect of idea]

As explained above, according to the present invention, the connection between the sub gear and the main gear can be achieved by a knock pin implanted in the main gear (or the sub gear), and a backless gear device that is easy to manufacture can be obtained.

Also, since the spring can be preset for the sub-gear, the sub-gear (sub-assembly 5 as one part) with the spring temporarily set can be attached to the camshaft to which the main gear is attached, and the spring is attached to the side of the assembly line. Assembling and assembling is very easy since all you need to do is prepare the sub-gear.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of a backless gear device according to the present invention, Fig. 2 is a partial sectional plan view of the backless gear device in an assembled state, and Fig. 3 is a backless gear installed on a camshaft. Partially cutaway perspective view of the device, No. 4
5 is a schematic diagram showing the teeth in the free state; FIG. 6 is a cross section similar to FIG. 4 in the resiliently biased state. 7 is a schematic diagram of the tooth in a state of meshing with a mating gear, FIG. 8 is a diagram showing the state of pin wear, and FIG. 9 is a diagram showing the relationship between spring displacement and spring force. 1... Backless gear device, 2... Main gear, 3... Sub gear, 4... C clip type spring, 5, 6... Teeth,
11, 12...pin, 13, 14...elongated hole, 17...knock pin, 18...third hole.

Claims (1)

[Scope of utility model registration request] It consists of two gear elements having the same tooth profile and the same number of teeth and one C-clip-shaped spring, and two pins are erected on one end surface of one gear element.
and a hole is formed at each end of the C-clip type spring so that the C-clip type spring can be attached to the one gear element by engaging each pin with the hole; at least one of the holes in each end of the spring is larger than the size of the pin engaging it so that it can be deformed after the C-clip shaped spring is attached to said one gear element, and the other A knock pin that fits into the third hole formed in the C-clip spring is erected on one end surface of the gear element, and the two gear elements sandwich the spring so that the end surfaces thereof face each other. A backless gear device characterized in that when coaxially combined, both gear elements are elastically connected via the spring so as to be able to rotate relative to each other by fitting the third hole and the knock pin. .