JP2009281401A - Constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely suppress excessive deformation of a boot without damaging sealing performance in a joint inner space. <P>SOLUTION: This constant velocity universal joint is provided with an inner ring 1 jointed to a shaft 5, an outer ring 2 arranged on the outer peripheral side of the inner ring 1, and a plurality of balls 3 performing torque transmission between the inner ring 1 and the outer ring 2. The boot 7 for closing one end opening part of the outer ring 2 together with the shaft 5 is fitted to one end opening part side of the outer ring 2, and a seal plate 8 for closing the other end opening part of the outer ring 2 is fitted to the other end opening part side of the outer ring 2. A through-hole 8c is formed on the seal plate 8, and the through-hole 8 is closed by a sheet material 11 consisting of an elastic body deformable in accordance with volume fluctuation in the joint inner space. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a constant velocity universal joint used in, for example, a propeller shaft and a drive shaft of an automobile or various industrial machines.

  In an FR vehicle, an engine, a clutch, a transmission (transmission) are arranged at the front, a reduction gear device (differential), and a drive axle are arranged at the rear. . Further, the FR-based 4WD vehicle requires a rear propeller shaft and a front propeller shaft. These propeller shafts are equipped with constant velocity universal joints to accommodate changes in length and angle due to changes in relative position between the transmission and the differential.

  This type of constant velocity universal joint includes an inner ring coupled to a shaft, an outer ring disposed on the outer peripheral side of the inner ring, and a torque transmission member (for example, a plurality of balls) that transmits torque between the outer ring and the inner ring. It is known that a rubber boot is attached to one end opening side of the outer ring and a metal seal plate is attached to the other end opening side of the outer ring. Among these configurations, the boot and the seal plate are provided in order to prevent leakage of grease filled in the joint and to prevent foreign matter from entering from the outside of the joint.

  However, in this type of constant velocity universal joint with the joint internal space sealed, excessive deformation of the boot is caused by expansion of gas inside the joint due to heat generation during high-speed rotation and contraction of gas inside the joint during decompression. This may occur and may cause a problem that the durability of the boot is reduced.

Therefore, from the viewpoint of preventing excessive deformation of the boot, a vent hole communicating with the inside and outside of the joint is formed in the boot (for example, see Patent Documents 1 and 2 below), and such a vent hole is formed on the seal plate. (For example, refer to Patent Document 3 below) has been proposed. All of these are intended to prevent over-deformation of the boot by ensuring the balance of the joint internal / external pressure via the vent holes.
Japanese Utility Model Publication No. 7-44969 JP-A-8-28704 Japanese Utility Model Publication No. 1-166826

  However, in the former configuration in which the vent is formed in the boot, the boot must be partially cut away by forming the vent, so that the durability of the boot is inevitably lowered. In addition, since the inside of the joint communicates with the outside of the joint through the vent hole, grease may leak through the vent hole, or foreign matter may enter from the outside of the joint, and the sealing performance of the joint inner space is improved. There is a risk of damage.

  On the other hand, with the latter configuration in which the vent holes are formed in the seal plate, it is possible to prevent the situation where the boot durability decreases due to the vent holes, as in the configuration in which the vent holes are formed in the boot. From the viewpoint of doing, it seems to be preferable. However, in this case as well, there is a possibility that grease may leak through the air holes formed in the seal plate or foreign matter may enter from the outside of the joint, and the sealing performance of the joint internal space may still be impaired.

  Therefore, even if the conventional method as described above can prevent excessive deformation of the boot, the sealing function originally required for the boot and the seal plate is impaired. For this reason, the situation is that both prevention of excessive deformation of the boot and securing of the sealability of the joint internal space cannot be achieved at the same time.

  In view of the above circumstances, an object of the present invention is to reliably suppress excessive deformation of a boot without impairing the sealing performance of the joint internal space.

  The present invention devised to solve the above problems includes an inner member coupled to a shaft, an outer member disposed on the outer peripheral side of the inner member, the inner member, and the outer member. A torque transmission member that transmits torque between the first member and the other end of the outer member. A boot that closes one end opening of the outer member together with the shaft is attached to the other end of the outer member. In a constant velocity universal joint in which a seal plate that closes the opening is mounted on the other end opening side of the outer member, a through hole is formed in the seal plate, and the through hole is used to change the volume of the joint internal space. Accordingly, the sheet is closed with a deformable sheet material.

  According to such a configuration, even when the volume of the joint internal space fluctuates due to a change in internal pressure due to heat generation or the like during high-speed rotation, the volume fluctuation can be absorbed by deformation of the sheet material. That is, when the gas inside the joint expands, the sheet material is deformed so as to swell toward the outside of the joint. On the contrary, when the gas inside the joint contracts, the sheet material is recessed toward the inside of the joint. By deforming in this manner, volume fluctuations in the joint internal space can be absorbed. Moreover, since such an effect can be enjoyed by deformation of the sheet material, the inside and outside of the joint are actively communicated as in the case where a seal plate and a vent hole communicating with the inside and outside of the joint are formed in the boot. Therefore, the sealing performance of the joint inner space can be ensured reliably.

  Said structure WHEREIN: It is preferable that the said sheet | seat material is formed with the elastic body.

  If it does in this way, since it becomes easy to deform | transform a sheet | seat material according to the volume fluctuation | variation of a joint internal space, it becomes possible to follow exactly by the volume fluctuation | variation of a joint internal space.

  In this case, the seal plate has a press-fit portion that is press-fitted and fixed to the inner peripheral surface of the other end opening of the outer member, and the outer surface of the seal plate including the outer peripheral surface of the press-fit portion is the elastic body. It may be covered with the sheet material formed in (1).

  In this way, since the sheet material formed of an elastic body covers the outer surface of the press-fit portion, the sheet material is compressed and deformed when press-fitted and fixed to the outer member. Therefore, once the seal plate is press-fitted and fixed to the outer member, it is possible to ensure high sealing performance by the elastic restoring force of the sheet material. Therefore, the sealability of the joint internal space can be improved by the sheet material.

  Said structure WHEREIN: It is preferable that the said sheet | seat material is formed with the material whose elastic modulus is higher than the said boot.

  In this way, the sheet material is elastically deformed preferentially over the boot, so that excessive deformation of the boot can be more reliably suppressed.

  Said structure WHEREIN: It is preferable that the said through-hole is formed in the center part of the said seal plate.

  In general, when the joint rotates, the grease filled in the joint internal space moves to the outer diameter side by centrifugal force. Therefore, if a through hole is formed in the center portion of the seal plate, the ratio of holding the grease to which the centrifugal force is applied decreases with the sheet material closing the through hole. That is, the situation that the sheet material is deformed by the weight of the grease can be suppressed.

  Said structure WHEREIN: It is preferable that the said through-hole is circular.

  In this way, when the sheet material is deformed according to the volume variation of the joint internal space, the deformation of the sheet material is smoother than when the through hole has a corner such as a square. Can be done.

  As described above, according to the present invention, even when the volume of the joint internal space fluctuates due to a change in internal pressure due to heat generation or the like during high-speed rotation, the volume fluctuation can be absorbed by the deformation of the sheet material. It is possible to reliably suppress the excessive deformation. Furthermore, since the effect of suppressing the excessive deformation of the boot can be enjoyed by the deformation of the sheet material, the inside and outside of the joint is formed like a seal plate and a vent hole communicating with the inside and outside of the joint. Will not be actively connected. Therefore, it is possible to reduce excessive deformation of the boot as much as possible while ensuring the sealing performance of the joint internal space.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a longitudinal sectional view showing a sliding type constant velocity universal joint according to an embodiment of the present invention. As shown in the figure, the constant velocity universal joint includes an inner ring 1 as an inner member, an outer ring 2 as an outer member, a plurality of balls 3 as torque transmitting members, and a cage 4 as main components. Yes.

  The inner ring 1 has a plurality of linear track grooves 1b extending in the axial direction on the spherical outer peripheral surface 1a. A shaft portion 5a of a shaft (drive shaft or driven shaft) 5 is inserted into the center hole of the inner ring 1, and torque transmission is made possible by connecting them together by spline fitting. A snap ring 6 is attached to the tip of the shaft portion 5 a of the shaft 5, and the shaft 5 is prevented from coming off from the inner ring 1.

  The outer ring 2 is disposed on the outer peripheral side of the inner ring 1, and a plurality of linear track grooves 2 b extending in the axial direction are formed on the cylindrical inner peripheral surface 2 a in pairs with the track grooves 1 b of the inner ring 1. A ball 3 is incorporated between the track groove 1 b of the inner ring 1 and the track groove 2 b of the outer ring 2 that form a pair. The cage 4 is disposed between the spherical outer peripheral surface 1 a of the inner ring 1 and the cylindrical inner peripheral surface 2 a of the outer ring 2, and the ball 3 is held in the pocket 4 a of the cage 4 so as to be able to roll.

  Further, a rubber boot 7 is attached to one end opening side of the outer ring 2, and a metal seal plate 8 is attached to the other end opening side, and both ends of the outer ring 2 are supported by the boot 7 and the seal plate 8. The opening is closed.

  More specifically, the boot 7 has a large-diameter portion 7a, a small-diameter portion 7b, and an intermediate portion 7c having a U-shaped cross section that connects the large-diameter portion 7a and the small-diameter portion 7b. A small-diameter portion 7 b of the boot 7 is attached to the shaft 5 and fastened by a boot band 9 to be fixed. The large-diameter portion 7 a of the boot 7 is fixed to the one end opening portion side of the outer ring 2 through a metal boot adapter 10.

  On the other hand, the seal plate 8 includes a top plate portion 8a that covers the other end opening of the outer ring 2, and a cylindrical press-fit portion 8b that protrudes from the periphery of the top plate portion 8a. The press-fit portion 8 b of the seal plate 8 is press-fitted and fixed to the inner peripheral surface 2 a on the other end opening side of the outer ring 2.

  Further, a circular through hole 8c is formed at the center of the top plate portion 8a of the seal plate 8, and this through hole 8c is closed by a sheet material 11 that can be deformed according to the volume variation of the joint internal space. Yes. The sheet material 11 is formed of an elastic body (for example, rubber) having a higher elastic coefficient than that of the boot 7.

  The size of the sheet material 11 is not particularly limited as long as the through hole 8c can be closed, but in this embodiment, the sheet material 11 covers the outer peripheral surface of the press-fitting portion 8b of the seal plate 8. The sealing plate 8 is adhered and fixed to the outer surface of the sealing plate 8 in a state where the entire outer surface of the sealing plate 8 is covered. This is because the sealing performance between the outer ring 2 and the seal plate 8 is enhanced by the sheet material 11 formed of an elastic body.

  The constant velocity universal joint configured as described above transmits the rotational force applied by the drive shaft to the driven shaft when the outer ring 2 and the inner ring 1 rotate integrally.

  At this time, the volume of the joint internal space may fluctuate due to a change in internal pressure due to heat generation or the like during high-speed rotation. The change in the volume is caused by the sheet material 11 closing the through hole 8c of the seal plate 8. It can be absorbed by elastic deformation. That is, when the gas in the joint internal space expands, as shown in FIG. 2, the sheet material 11 is deformed so as to expand to the joint outer side, and conversely, when the gas in the joint internal space contracts. As shown in FIG. 3, the sheet material 11 is deformed so as to be recessed toward the inside of the joint. Therefore, the elastic deformation of the sheet material 11 can absorb the volume fluctuation of the joint internal space. Moreover, since the volume variation of the joint internal space is absorbed by the elastic deformation of the sheet material 11, the inside and outside of the joint are formed as in the case where the seal plate 8 and the boot 7 are formed with vent holes communicating with the inside and outside of the joint. Since it is not necessary to positively communicate with each other, it is possible to ensure the sealing performance of the joint internal space. Since these deformations are elastic deformations, the sheet material 11 returns to the original state shown in FIG. 1 when the pressure in the joint internal space returns to a steady state of about atmospheric pressure.

  Further, since the sheet material 11 is formed of a material having a higher elastic coefficient than that of the boot 7, the sheet material 11 is elastically deformed preferentially over the boot 7 and more reliably suppresses excessive deformation of the boot 7. Can do.

  Furthermore, the grease filled in the joint inner space moves to the outer diameter side due to the centrifugal force acting during rotation. Therefore, if the through-hole 8c is formed in the center part of the seal plate 8 as described above, the ratio of holding the grease to which the centrifugal force is applied decreases in the sheet material 11 that closes the through-hole 8c. That is, the situation that the sheet material 11 is deformed by the weight of grease can be suppressed.

  Further, since the through hole 8c has a circular shape, when the sheet material 11 is deformed in accordance with the volume variation of the joint internal space, for example, the shape of the through hole 8c is a corner portion such as a square. The sheet material 11 can be smoothly deformed.

  In addition, this invention is not limited to said embodiment, In the range which does not deviate from the summary of this invention, it can implement with a various form further.

  For example, in the above-described embodiment, the boot 7 having a U-shaped cross section having the intermediate portion 7c has been described as an example. However, even a bellows-shaped boot having a bent portion used for a drive shaft may be used. Good.

It is sectional drawing which shows typically the whole structure of the sliding type constant velocity universal joint which concerns on one Embodiment of this invention. It is an enlarged view which expands and shows the X area | region shown in FIG. 1, Comprising: It is a figure which shows a state when the volume of joint internal space expand | swells. It is an enlarged view which expands and shows the X area | region shown in FIG. 1, Comprising: It is a figure which shows a state when the volume of joint internal space shrink | contracts.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Ball 4 Cage 5 Shaft 6 Snap ring 7 Boot 8 Seal plate 8a Top plate part 8b Press-fit part 8c Through-hole 9 Boot band 10 Boot adapter 11 Sheet material

Claims (6)

An inner member coupled to the shaft, an outer member disposed on the outer peripheral side of the inner member, and a torque transmission member that transmits torque between the inner member and the outer member, A boot that closes one end opening of the outer member together with the shaft is attached to one end opening side of the outer member, and a seal plate that closes the other end opening of the outer member is the other member of the outer member. In the constant velocity universal joint mounted on the end opening side,
A constant velocity universal joint characterized in that a through hole is formed in the seal plate, and the through hole is closed with a sheet material that can be deformed in accordance with a volume variation of the joint internal space.   The constant velocity universal joint according to claim 1, wherein the sheet material is formed of an elastic body.   The seal plate has a press-fit portion that is press-fitted and fixed to the inner peripheral surface of the other end opening of the outer member, and the outer surface of the seal plate including the press-fit portion is formed of the elastic body. The constant velocity universal joint according to claim 2, wherein the constant velocity universal joint is covered with a sheet material.   The constant velocity universal joint according to any one of claims 1 to 3, wherein the sheet material is formed of a material having a higher elastic coefficient than that of the boot.   The constant velocity universal joint according to any one of claims 1 to 4, wherein the through hole is formed in a central portion of the seal plate.   The constant velocity universal joint according to any one of claims 1 to 5, wherein the through hole is circular.

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