JPS6158975A - Distributor drive mechanism in internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce variations in revolution of the drive mechanism of a distributor to prevent component parts from being broken, by providing an intermediate gear for driving the distributer in addition to a cam gear for driving a cam shaft, and by meshing the cam shaft and the intermediate gears with a timing belt. CONSTITUTION:A timing belt 1 drives a cam gear 21 in a cam drive system 2, and the cam gear 21 is fixed to a cam shaft 22 with bolts 23, and meshes with an intermediate gear 61 to drive a distributor driven gear 7 in a distributor through a drive shaft 64 and a drive gear 68. Thus, variations in revolution of the distributor drive system may be reduced to prevent the ignition timing from shifting, thereby it is possible to prevent component parts from being broken.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distributor drive machine 611 for driving an ignition system distributor (including a breaker) in an internal combustion engine. [Prior Art 1] Conventionally, the drive system of a distributor in an internal combustion engine has a configuration in which power is transmitted by a distributor drive gear integrally provided on a camshaft, as shown in, for example, Japanese Utility Model Application Publication No. 54-174732. A representative example of these conventional techniques is shown in FIG. 4 and explained.A cam gear C driven by a timing belt a from the engine crankshaft rotates at 1/2 the speed of the engine rotation.
The cam gear C drives the camshaft 1). A distributor drive gear C for rotating the driven shaft d of the distributor is attached to the end of the camshaft. A cam f'' is provided on the camshaft 1) for operating the rocker arm of the valve mechanism, and the rocker arm g is shown in Fig. 5 (i>
, GO, normally it is always pressed upward by a spring h, but when opening the intake/exhaust valve, the valve k is pushed down to open the intake/exhaust valve k. [Problems to be solved by the invention] In the above-mentioned prior art, the problems to be solved by the prior art are shown in FIG. 5 (i>, 6i) and FIG. 6 (1). (ii), (Explaining using iiD, Fig. 6 <1)
In the normal state where the load on the ram shaft is small, the cam gear C is driven by the timing belt a in the six directions of the arrows. Next, when the intake and exhaust valves k are operated as shown in FIG. Figure 6 Gr)
As shown in , a strong load is applied to the teeth of timing bells 1 to a in the direction of arrow B so that the teeth of belt a are deformed (deformed as indicated by 111D in the figure). Conversely, when the intake and exhaust valve strings move in the closing direction as shown in Figure 5 (ii), the spring h
The elasticity acts in the same direction as the rotation direction of the camshaft, and as shown in Fig. 6
1i>, almost no load is applied to the teeth of the timing belt a. Since the opening and closing operations of the intake and exhaust valves are performed continuously, the rotation of the camshaft relative to the belt a causes large rotational fluctuations in the relationship between the belt a and the camshaft. Therefore, with the conventional technology, there is a problem in that the rotational fluctuation of the cam Ij*b is directly transmitted to the distributor, causing a shift in ignition timing and damage to the distributor and similar breakers, especially in engines with a small number of cylinders. In 1, unlike the case where the load of multiple cylinder valves is offset, the cam @l by the intake and exhaust valve k
The lb rotational fluctuation was large, and the above problem was significant. [Object of the invention] The present invention aims to solve the problems in the prior art described above.
This is an improved distributor drive that reduces rotational fluctuations in synchronized rotation with the cam in the drive system when driving the distributor, prevents ignition timing deviation, and prevents damage to parts. The purpose is to provide a mechanism. Hereinafter, in the present invention, the term "distributor" refers to an ordinary distributor that rotates in synchronization with the rotation of the engine, a breaker included therein, and the like. Configuration of the Invention In order to achieve the above-mentioned object, the configuration of the present invention includes an intermediate gear for driving a distributor in addition to a cam gear that drives a camshaft in an internal combustion engine, and the cam gear and the intermediate gear are arranged coaxially in parallel and meshed with a timing belt, and rotational power is transmitted from the intermediate gear to the distributor via the distributor drive gear, so that the distributor is rotationally driven independently of the camshaft. It is characterized by: [Embodiment 1] Hereinafter, one embodiment of the present invention will be specifically described based on the drawings. FIG. 1 shows an embodiment of a distributor drive mechanism in an internal combustion engine to which the present invention is applied, and reference numeral 1 denotes a timing belt driven by the crank teeth IO of the internal combustion engine. The cam gear 21 of the cam drive system 2 that meshes with nearly 3/4 of the width is driven, and the cam gear 21 is fixed to the camshaft 22 with a bolt 23, and the camshaft 22 is connected to the crankcase 3 via a bushing 4 to drive the cam @ Each cam 25 of the camshaft 22 actuates each rocker arm 5 of the valve mechanism. On the other hand, the distributor drive system 6 has an intermediate gear 61 for driving the distributor that meshes with teeth of about 1/4 of the belt width with respect to the timing belt 1, and this intermediate gear 61 is supported by bearings (32, 63). The drive shaft 64 is fixed to the distributor drive shaft 64 with a bolt 65, and this drive @64 is connected to the cam gear 21 and the cam shaft 2.
2 through the hollow part 2G of the crankcase 3, and the other end 31 of the crankcase 3.
Distributor drive teeth 1968 are fixed by bolts 69 via thrust bearings 66 on the outside of J.
5. This drive gear 68 drives the distributor driven gear 7 of the distributor. Next, the operation of the distributor drive mechanism having the above-mentioned configuration will be explained. Due to the vibration of the valve mechanism, the camshaft 22 rotates at a variable speed with respect to the drive speed of the timing belt 1, as explained in β2 in the problem to be solved by the invention. However, the drive system of the distributor 1-rebuter drive gear 68 is independent of the drive system of the cam@22, and the distributor intermediate gear 61 independently meshes with the timing belt 1, and its meshing portion Since the rotational fluctuations of the camshaft 22 are absorbed at , the rotational fluctuations are not transmitted to the intermediate gear 61 . Therefore, the distributor drive shaft 64 is directly driven by the timing belt 1 at a smooth speed with little fluctuation, and the distributor 1 to the repeater are rotated in synchronization with the rotation of the crankshaft. The above-mentioned embodiment shows an example in which the camshaft 22 is made hollow and the distributor drive shaft 64 is inserted inside it.
In the present invention, the cam shaft and the distributor drive 1 need only be driven independently, and as another embodiment, a distributor drive mechanism as shown in FIGS. 2 and 3 may be used. That is, as in the embodiment shown in FIG.
Fit the base end of the cam gear 21a and drive the cam gear 21a! VJ(!f
The J wheel (31a) may be independently meshed with the timing belt 1, and as roughly shown in the third factor, a disco The gear G1bJ5 and the distributor drive #J#1 wheel 6ab may be supported by a bearing 331+ that is separate from the camshaft 22b. Since the distributor drive shaft is driven by the camshaft, rotation is accurately synchronized with 1/2 of the engine rotation speed, and smooth rotational drive is ensured without being affected by rotational fluctuations of the camshaft. The advance angle by the advance angle device is stable, the ignition timing is stable and does not shift, and there is no sudden rotational fluctuation or vibration from the camshaft on parts such as the advance device, reducing the burden on the camshaft. Effects such as being able to prevent damage can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of a distributor drive mechanism in an internal combustion engine to which the present invention is applied, Fig. 2 is a sectional view of another embodiment, and Fig. 3 is a sectional view of another embodiment. , FIG. 4 is a sectional view of a conventional distributor drive mechanism, and FIGS. 5 and 6 are explanatory diagrams illustrating the operation of the conventional mechanism. 1... Timing belt, 21... Cam gear, 22
...Camshaft, 61...Distributor intermediate gear, 64...Distributor drive shaft, 68...Distributor drive gear. Patent Applicant: Agent for 7 Baju Heavy Industries Co., Ltd. Patent Attorney: Nobu Kobashi Ukiyo Patent Attorney: Susumu Murai Figure 1 (i) (ii) (iii) Figure 2 Figure 3 and j Figure 4 and Figure 5

Claims (1)

[Claims] Separately from the cam gear that drives the camshaft, there is an intermediate gear for driving the distributor, and these cam gears and the intermediate gear are coaxially aligned and meshed with the timing belt, and the intermediate gear is connected to the intermediate gear via the distributor driving gear. A distributor drive mechanism for an internal combustion engine, characterized in that the distributor is configured to be rotationally driven independently of a camshaft by transmitting rotational power to the distributor.