JP2000337395A - Propeller shaft with ball spline mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the pressure variation of the blocking space in a dust sleeve when a sleeve yoke and a spline shaft are displaced in the axial direction, and to prevent the invasion of a muddy water into the blocking space. SOLUTION: In this propeller shaft, a shaft which consists of a hollow shaft (propeller shaft) 41 and a spline shaft 42, and a tubular yoke (sleeve yoke) 2, are engaged through a ball spline mechanism 5, and near the front end of the tubular yoke 2 is covered by a dust sleeve whose one side end is fixed to the spline shaft 42, while its other side end is sliding contacted to the outer peripheral surface of the tubular yoke 2. In this case, a blocking space G in the dust sleeve 6 is communicated to the inner space H of the hollow shaft 41 by a through hole 420 for air removing formed to the spline shaft 42. As a result, the pressure variation in the blocking space G can be prevented without opening the through hole 420 for air removing directly to the outer side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propulsion shaft for transmitting power to an automobile or the like, and more particularly to a propulsion shaft provided with expansion and contraction ball spline mechanisms between universal joints provided at both ends. The present invention relates to a propulsion shaft with a ball spline mechanism.

[0002]

2. Description of the Related Art Propulsion shafts used as propeller shafts for medium-sized trucks and buses, for example, often use a ball spline mechanism between universal joints at both ends to facilitate expansion and contraction of the shaft. Have been.

[0003] In such a propulsion shaft with a ball spline mechanism, as shown in a partial cross-sectional view of a conventional structure example in Fig. 3, one of the universal joints 1a has a base end of a sleeve yoke 2 as a cylindrical yoke. And the other end of the universal joint 1b is connected to the base end of a shaft 4 via a weld yoke 3, and the shaft 4 and the sleeve yoke 2 are rotated about an axis by a ball spline mechanism 5. Are joined so as to be able to transmit and smoothly displace each other in the axial direction.

[0004] That is, the shaft 4 is composed of a propeller tube 41 consisting of a hollow shaft with a welded yoke 3 welded to its base end, and a spline shaft 42 welded to its tip.
Are formed with ball spline grooves on the outer peripheral surface. On the other hand, a ball spline groove is also formed on the inner peripheral surface of the sleeve yoke 2, and the ball spline mechanism 5 uses the sleeve yoke 2 as an outer shaft, the spline shaft 42 as an inner shaft, and each ball spline between them. The main elements are a plurality of balls 51 arranged in the groove and a spring 52 for urging and pressing each ball 51 from both axial sides in each ball spline groove.

In order to prevent foreign matter such as dust from entering the ball spline mechanism 5, the vicinity of the tip of the sleeve yoke 2 is covered with a dust sleeve 6.
One end of the dust sleeve 6 has a spline shaft 42.
Is fixed to the flange portion 421 formed on the outer periphery of the sleeve yoke 2, and the other end is slidably contacted with the outer peripheral surface of the sleeve yoke 2 via the dust seal 61, so that the other end is formed at the tip end of the sleeve yoke 2. The space including the open portion is sealed from the outside to prevent entry of foreign matter into the ball spline mechanism 5.

Here, the closed space G in the dust sleeve 6
FIG. 4 is a diagram for preventing the pressure fluctuation in the closed space G because the volume thereof changes when the sleeve yoke 2 and the spline shaft 42 are displaced in the axial direction and the pressure in the closed space G fluctuates. As shown in an enlarged view of a portion A in FIG. 3, an air vent hole 422 communicating with the outside is formed in the spline shaft 4.

[0007]

By the way, in the conventional propulsion shaft with a ball spline mechanism as described above,
Since the air vent hole 422 is open to the outside to allow the closed space G in the dust sleeve 6 to communicate with the outside, there is a problem that muddy water easily enters the closed space G through the air vent hole 422. Was. Here, although a felt seal or the like is interposed between the inner peripheral surface of the distal end portion of the sleeve yoke 2 and the outer peripheral surface of the spline shaft 42, muddy water that has entered the closed space G removes the felt seal or the like. There is a danger that it will penetrate into the ball spline mechanism 5 and deteriorate its function.

The present invention has been made in view of such circumstances, and prevents the pressure fluctuation in the closed space G in the dust sleeve 6 when the sleeve yoke 2 and the spline shaft 42 are displaced in the axial direction. Moreover, it is an object of the present invention to provide a propulsion shaft with a ball spline mechanism that prevents muddy water or the like from entering the closed space G.

[0009]

In order to achieve the above object, a propulsion shaft with a ball spline mechanism according to the present invention has a universal joint at both ends, and a cylindrical joint having a base end connected to one universal joint. And a shaft whose base end engages the other universal joint engages via a ball spline mechanism, and the shaft is a hollow shaft connected to the other universal joint and a distal end thereof. And a spline shaft that forms the inner shaft of the ball spline mechanism and is fixed at one end to the outer periphery of the spline shaft outside near the tip of the cylindrical yoke,
In a propulsion shaft with a ball spline mechanism, the other end of which is covered by a dust sleeve that is in sliding contact with the outer periphery of the cylindrical yoke, the space in the dust sleeve is defined by an air vent through hole formed in the spline shaft. It is characterized by communicating with the inside of the hollow shaft.

According to the present invention, an air vent hole for preventing pressure fluctuation in a closed space in a dust sleeve is not opened directly to the outside, but is opened in a hollow shaft (propeller tube). It seeks to achieve its intended purpose.

That is, in this type of propulsion shaft, the shaft is conventionally mainly composed of a hollow shaft (propeller tube) for the purpose of weight reduction and the like, and the spline shaft is fixed to the tip of the spline shaft. Therefore, the internal space of this hollow shaft is adjacent to the closed space in the dust sleeve with the spline shaft interposed, and a through hole connecting to both spaces is formed in the spline shaft to connect these two spaces. Can be done. The internal space of the hollow shaft is usually communicated with the outside by a hole formed in the weld yoke, for example, in order to allow the air expanded by the heat when welding the weld yoke and the spline shaft to both ends thereof to escape to the outside of the hollow shaft. Because
The pressure fluctuation during the axial displacement of the sleeve yoke and the spline shaft is prevented without directly opening the air vent hole in the closed space in the dust sleeve to the outside, thus preventing the intrusion of muddy water and the like. Can be suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view showing the entire configuration of an embodiment of the present invention, and FIG. 2 is an enlarged view of the vicinity of the ball spline mechanism 5.

The basic structure of the propulsion shaft in this embodiment is the same as that shown in FIG. 3, and universal joints 1a and 1b are provided at both ends, respectively. The base end of a cylindrical sleeve yoke 2 is connected to 1a, and the base end of a shaft 4 is connected to the other universal joint 1b via a weld yoke 3. Each of the universal joints 1a and 1b has a known structure in which the sleeve yoke 2 or the weld yoke 3 and the cylindrical hole yoke 7a or 7b are connected by cross bearings 11a and 11b, respectively.

The shaft 4 is composed of a propeller tube (hollow shaft) 41 with a welded yoke 3 welded to the base end and a spline shaft 41 welded to the tip end, similarly to the shaft shown in FIG. ing. Further, ball spline grooves are formed on the outer peripheral surface of the spline shaft 4 and the inner peripheral surface of the sleeve yoke 2, respectively. A plurality of balls 51 are provided in each of the ball spline grooves therebetween. A spring 52 that presses and biases the ball 51 to both sides in the axial direction is disposed.
The ball spline mechanism 5 is formed by these components. The sleeve yoke 2 which is the outer shaft of the ball spline mechanism 5 and the spline shaft 42 which is the inner shaft are mutually displaceable in the axial direction, and are mutually displaceable around the axis. , So that rotation can be transmitted by non-slip engagement. In FIG. 2, 81 is a bush, 82 is a retainer washer, 83 is a felt seal, and 84 is a spacer.
85 is a C-shaped retaining ring.

A felt seal 83 is provided at an opening between the inner peripheral surface of the distal end of the sleeve yoke 2 and the outer peripheral surface of the spline shaft 42 to prevent foreign substances such as dust from entering. In order to prevent foreign matter such as dust from reaching the opening, the vicinity of the distal end of the sleeve yoke 2 is covered with a dust sleeve 6 as in the conventional example of FIG. One end of the dust sleeve 6 is fixed to the outer peripheral surface of a flange portion 421 formed near the end of the spline shaft 42 on the joint side with the propeller tube 41, and the other end is connected to the sleeve via a dust seal 61. Sliding contact with the outer peripheral surface of the yoke 2 forms a closed space G including the distal end opening of the sleeve yoke 2.

Now, the closed space G in the dust sleeve 6 will be described.
Is communicated with the internal space H of the propeller tube 41 by an air vent through hole 420 formed in the flange portion 421 of the spline shaft 42. The internal space H of the propeller tube 41 communicates with the outside through a hole 31 formed in the center of the weld yoke 3. The hole 31 is originally formed when the weld yoke 3 and the propeller tube 41 are welded, and when the propeller tube 41
A hole formed for the purpose of allowing air expanded in the internal space H of the propeller tube 41 to escape to the outside by heat generated during welding between the propeller tube 41 and
Due to the presence of the hole 31, the closed space G in the dust sleeve 6 communicates with the outside via the internal space H of the propeller tube 41 only by forming the air vent through hole 420 in the flange portion 421 of the spline shaft 42. Will be.

According to the above-described embodiment of the present invention, when the spline shaft 42 and the sleeve yoke 2 are relatively slid in the axial direction, the volume of the closed space G in the dust sleeve 6 changes. Since the closed space G communicates with the internal space H of the propeller tube 42 via the air vent through hole 420 and communicates with the outside via the hole 31, the internal pressure fluctuates due to the volume change. Absent. Further, the air vent through hole 420 opens toward the internal space H of the propeller tube 42 and does not directly open to the outside. There is no danger of muddy water etc. invading.

[0018]

As described above, according to the present invention, one end is fixed to the outer periphery of the spline shaft so as to cover the vicinity of the tip of the sleeve yoke, which is the opening of the ball spline mechanism, and the other end is formed of the sleeve yoke. The closed space in the dust sleeve that is in sliding contact with the outer peripheral surface is communicated with the internal space of the propeller tube by the air vent through hole formed in the spline shaft, and is communicated with the outside through the propeller tube. Therefore, even if the sleeve yoke and the spline shaft are relatively slid and displaced in the axial direction to change the volume of the closed space in the dust sleeve, the internal pressure does not change, and the pressure change is prevented. The air vent hole of the dust sleeve does not open directly to the outside as in the past, so that the air inside the dust sleeve is closed through the air vent hole. Muddy water or the like may not be to enter the space.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing an entire configuration of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a detailed structure near a ball spline mechanism 5 in FIG.

FIG. 3 is a partial sectional view showing a configuration example of a conventional propulsion shaft with a ball spline mechanism.

FIG. 4 is an enlarged view showing a detailed configuration of a portion A in FIG. 3;

[Explanation of symbols]

 1a, 1b Universal Joint 2 Sleeve Yoke 3 Weld Yoke 4 Shaft 41 Propeller Tube (Hollow Shaft) 42 Spline Shaft 420 Air Vent Through Hole 421 Flange 5 Ball Spline Mechanism 51 Ball 52 Spring 6 Dust Sleeve 61 Dust Seal G Closed Space H Propeller Internal space of tube 41

Claims (1)

[Claims] A cylindrical yoke having a universal joint at both ends and a base end connected to one universal joint, and a shaft having a base end engaged with the other universal joint form a ball spline mechanism. And the shaft comprises a hollow shaft connected to the other universal joint and a spline shaft fixed to a tip end of the hollow shaft to form an inner shaft of the ball spline mechanism. An outer end near the tip of the cylindrical yoke is propelled with a ball spline mechanism, one end of which is fixed to the outer periphery of the spline shaft and the other end of which is covered by a dust sleeve which is in sliding contact with the outer periphery of the cylindrical yoke. In the shaft, the space in the dust sleeve is communicated with the inside of the hollow shaft by an air vent through hole formed in the spline shaft. Ball spline mechanism with a propeller shaft to be.