JPH0665646U - Engine crankshaft - Google Patents

Abstract

(57) [Abstract] [Purpose] To suppress the noise from the recess provided at the end of the crankshaft. [Structure] A concave portion 2 is provided in an end surface 1A of a crankshaft 1, and a sound absorbing member 4 that rotates integrally with the crankshaft 1 is housed in the concave portion 2, and a hollow portion 2A is provided between the sound absorbing member 4 and the concave portion 2. Define.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to reducing noise and vibration generated in an engine crankshaft.

[0002]

[Prior art]

 It is known to form a hollow recess at the end of the crankshaft of the engine to reduce the weight. As shown in FIG. 3, a hollow recess 2 is provided at the end 1A of the crankshaft 1 of the engine 10. The crank pulley 6 and the crank damper 7 are coupled to each other through the fitted collar 3, and the concave portion 2 is formed to reduce the weight of the crankshaft 1. However, since the vibration inside the engine 10 is transmitted to the end surface 1A, this vibration may be transmitted from the recess 2 to the air and may be transmitted to the outside as noise, thus suppressing the generation of noise from the recess 2. For this reason, as disclosed in Japanese Utility Model Laid-Open No. 55-61653, there is known one in which a lid is provided on the end surface of the recess to suppress noise.

[0003]

[Problems to be solved by the device]

 However, the above-mentioned conventional crankshaft has a problem in that the lid provided on the end face may resonate to generate noise.

Therefore, an object of the present invention is to provide a crankshaft of an engine capable of suppressing noise generated in a recess provided in an end portion of the crankshaft.

[0005]

[Means for Solving the Problems]

 According to the present invention, a recess is provided at an end of a crankshaft, and a sound absorbing member that rotates integrally with the crankshaft is housed inside the recess, and a predetermined space is provided between the sound absorbing member and the recess. To define the space of.

[0006]

[Action]

 The vibration from the crankshaft is transmitted to the space defined by the sound absorbing member, but the sound absorbing member installed inside the recess absorbs the vibration of the air inside the space, reducing the noise generated from the recess. can do.

[0007]

【Example】

 FIG. 1 shows an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a crankshaft rotatably supported by an engine 10, and a hollow recess 2 having a predetermined circular cross section is provided on an end surface 1 A of the crankshaft 1 coaxially with the axis of the crankshaft 1. Is formed to a predetermined depth from the end surface 1A, and the weight of the crankshaft 1 is reduced by the recess 2.

The outer periphery of the collar 3 having a predetermined thickness is coaxially fitted to the inner periphery of the recess 2 and is supported by the crankshaft 1 and rotates integrally, and one end of the collar 3 is While protruding from the end face 1A to a predetermined position toward the outside (left side in the figure), a predetermined gap is formed between the other end of the collar 3 and the inner circumference of the recess 2 to define a hollow portion 2A described later. Prepare

A disk-shaped crank damper 7 for suppressing torsional vibration of the crankshaft 1 and a bottom of a crank pulley 6 for driving an auxiliary machine (not shown) are provided on the inner circumference of the collar 3. Mating with.

One surface of the crank damper 7 abuts on the end surface 1 A of the crankshaft 1, and the other surface abuts on the bottom portion of the crank pulley 6. Also, the crank damper 7 is fastened to the crank shaft 1 and integrally rotates.

The sound absorbing member 4 is housed over the entire length of the inner circumference of the collar 3, and the sound absorbing member 4 is formed of, for example, a substantially cylindrical foam rubber or a vibration-proof rubber. A hollow portion 2A is defined as a predetermined space between the end surface on the side and the recess 2, and the sound absorbing member 4 is hollow by fitting or fixing the outer circumference of the sound absorbing member 4 to the inner circumference of the collar 3. 2A is insulated from the outside of the crankshaft 1, and rotates integrally with the crankshaft 1 via the color 3.

With the above-mentioned configuration, the operation will be described.

The crankshaft 1 rotates as the engine operates, and vibrations from a combustion chamber (not shown) or the like are transmitted to the inner periphery of the recess 2 and the collar 3.

The air in the hollow portion 2 A defined between the recess 2 and the sound absorbing member 4 vibrates with the transmitted vibration, but the hollow portion 2 A is made by the sound absorbing member 4 and the collar 3 of the crank shaft 1. In addition to being insulated from the outside, the vibration of the air inside the hollow portion 2A is absorbed by the sound absorbing member 4 so that it is not transmitted to the outside of the crankshaft 1.

Therefore, the air inside the concave portion 2 provided on the end surface 1 A of the crankshaft 1 tends to generate noise due to the vibration of the crankshaft 1, but the hollow portion 2 A is exposed to the outside through the sound absorbing member 4. Since it is insulated from the recess 2, noise from the recess 2 can be suppressed, the quietness of the crankshaft 1 can be improved, and at the same time, the weight of the crankshaft 1 can be reduced by the hollow portion 2A. it can.

FIG. 2 shows another embodiment, in which the inner circumference of the crank pulley 6 and the crank damper 7 fixed to the end surface 1A of the crankshaft 1 is replaced by the outer circumference of the boss 1B projecting from the end surface 1A instead of the collar 3. The sound absorbing member 40 is fitted in the inner periphery of the recess 2 formed in the inner periphery of the boss 1B in the same manner as in the first embodiment, and other configurations are the same as those in the first embodiment. It is the same.

Since the hollow portion 2A is insulated from the outside of the crankshaft 1 only by the sound absorbing member 40, noise can be further suppressed as compared with the first embodiment.

Although the recess 2 and the sound absorbing member 4 are formed in a circular cross section in the above embodiment, they may be formed in a polygonal cross section symmetrical to the axis of the crankshaft 1 although not shown. .

[0020]

[Effect of device]

 As described above, according to the present invention, the vibration transmitted from the crankshaft to the space defined by the recess can be suppressed by the sound absorbing member housed in the inner periphery of the recess, It is possible to reduce the weight of the crankshaft while reducing the noise generated from the crankshaft.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an essential part showing another embodiment.

FIG. 3 is a sectional view of a main part showing a conventional example.

[Explanation of symbols]

 1 Crankshaft 1A End face 2 Recessed part 2A Hollow part 4 Sound absorbing member

Claims (1)

[Scope of utility model registration request] 1. A recess is provided at an end of a crankshaft,
A crankshaft for an engine, wherein a sound absorbing member that rotates integrally with the crankshaft is housed in the inner periphery of the recess, and a predetermined space is defined between the sound absorbing member and the recess.