JPH01206121A - Universal joint - Google Patents

Abstract

PURPOSE:To simplify the construction without increasing the number of parts and reduce the cost by mounting a rolling body so as to be held in a concaved surface of an internal part integral with a primary shaft and make contact with the flat surface of an external part integral with a secondary shaft. CONSTITUTION:When a journal joint 10 makes turns at a joint angle, a rolling body 16 rolls on the flat surface of a secondary engaging part 15a, and the rolling body 16 and the secondary engaging part 15a make relative movements in the axial direction and the radial direction, respectively. The friction resistance therebetween during the relative movements may be reduced greatly. In this case, in conformity to the principal of the uniform motion used in the conventional uniform speed joint, the universal joint 10 turns at the uniform speed. The rolling body 16 is maintained in position by the concaved surface 20 formed in the primary engaging part 13a of the internal part 12 and rolls on the flat surface of the secondary engaging part 15a, on account of which the number of parts may be minimized and the cost be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a universal joint, and particularly to a universal joint suitable for use in a vehicle drive system.

(Prior Art) As a universal joint used in a vehicle drive system, there is a universal joint called a tripod type constant velocity joint. This consists of an inner part that is integral with the first shaft and has three trunnion shafts spaced equally apart in the circumferential direction; an outer part integral with a second shaft, having three extending guide grooves and disposed surrounding the inner part; and a roller rotatably supported by each of the trunnion shafts and sliding in each of the guide grooves. Equipped with. The portion of the guide groove that contacts the roller is formed to have an arcuate cross section, while the roller is formed so that its outer peripheral surface is spherical.

When the constant velocity joint is used by being incorporated into a vehicle drive system, the first axis and the second axis may form an angle, and the constant velocity joint may be rotated at a so-called joint angle. In this case, each roller moves relative to the outer part in the axial direction as the shaft rotates, and at the same time moves relative to the outer part in the radial direction. Vibrations are generated due to frictional resistance during this movement, causing discomfort to the occupants.

Various proposals have been made to suppress the vibrations.

In the universal joint described in Japanese Utility Model Application Publication No. 62-20225, the portion of the guide groove of the outer part that contacts the roller is formed to have a straight cross section, while the roller is formed to have a cylindrical shape. ing. A guide ring is disposed inside the roller, and the roller is supported on the trunnion shaft via the guide ring. The trunnion shaft is formed into a spherical surface that is convex toward the guide ring, and the guide ring is convex toward the trunnion shaft, and these parts are in contact with each other through the spherical surfaces.

In the universal joint described in JP-A No. 61-189:122, the portion of the guide groove of the outer part located outward in the radial direction of the roller is formed to have a straight cross section;
The roller is formed into a cylindrical shape. Interposed between the guide groove and the roller is a component having a U-shaped planar shape, the outer circumferential surface of which has an arcuate cross section, and the inner circumferential surface of which has a linear cross section. .

In the universal joint described in Japanese Utility Model Application Publication No. 61-114128, a plurality of needles for rotating the roller in the circumferential direction are arranged between the roller and the trunnion shaft, and the roller is connected to the trunnion inside these needles. A plurality of needles are arranged for movement in the axial direction of the shaft.

(Problems to be Solved by the Invention) The universal joints described in any of the above-mentioned publications have an increased number of parts and a complicated structure. Moreover, the parts newly added to form the unique universal joint require precision machining, which is time-consuming and causes high costs.

An object of the present invention is to provide a universal joint that can be simplified in structure without increasing the number of parts and can suppress increased costs.

(Means for Solving the Problems) A universal joint according to the present invention includes three first engaging portions that are arranged at equal intervals in the circumferential direction, extend in the radial direction, and have a concave curved surface. The inner part consists of three members arranged in the circumferential direction, each of these three members having an engaging piece at each end in the circumferential direction, and the engaging pieces are adjacent to each other. The first
an inner part that is integral with the first shaft and constitutes an engaging part; and a second outer part that surrounds the inner part and has a recess formed by two planes that receives each of the engaging parts.
The second engaging portion is provided at equal intervals in the circumferential direction.
an outer part that is integral with the axis of the inner part, and a surface in each recess that is held in the concave curved surface of the first engaging part of the inner part and in contact with a flat surface of the second engaging part of the outer part. and arranged rolling elements.

Preferably, the three members constituting the inner part are formed in the same shape.

The concave curved surface of the inner part is outside the concave conical surface, concave spherical surface, concave elliptical surface,
The rolling element is formed into a shape such as a tetragonal surface or a concave polygonal surface.On the other hand, the rolling element is formed into a shape other than a sphere, in which the equatorial portion of the sphere is formed into a circular contour with a uniform diameter.

(Operations and Effects) Of the three members of the inner part, the rolling elements are sandwiched between the engaging pieces of two members arranged adjacent to t'L, and the members are fixed to each other, so that the rolling elements is attached to the inner part. This inner part is assembled into the outer part to complete the universal joint.

For example, the first shaft is coupled to the driving side and the second shaft is coupled to the driven side. The driving force or rotational torque transmitted from the first shaft passes through the inner part to the rolling element, from the rolling element to the outer part, and is taken out to the second shaft.

When the universal joint rotates at a joint angle, the rolling elements roll on the plane of the second engaging part, causing relative movement between the rolling elements and the second engaging part in the axial and radial directions. This greatly reduces frictional resistance during relative movement.

In this case, the universal joint rotates at a constant velocity according to the same constant velocity principle as the conventional constant velocity joint.

Since the rolling element is held in place by a concave curved surface provided on the first engaging part of the inner part and rolled on the plane of the second engaging part, the number of parts is not as described in the above-mentioned publication. The number of joints can be significantly reduced compared to conventional universal joints, and the structure is simpler. Thus, cost reduction is possible.

The inner part consists of three members, and the rolling elements are held by closely fixing the engaging pieces of adjacent members to each other, making it easy to process the concave curved surface of the inner part.

(Example) The universal joint 10 includes an inner part 12, an outer part 14, and rolling elements 16, as shown in FIGS. 1 and 2.

The inner part 12 includes three engaging portions 13a arranged at equal intervals of 120° in the circumferential direction and extending in the radial direction;
It has a central cylindrical boss portion 13b. Inner part 12
is coupled to shaft 18 as described below. Each engaging portion 13a
is substantially a rectangular parallelepiped, and is formed such that the length of the shaft 18 in the axial direction is greater than the thickness D in the direction perpendicular to the axis. The length is larger than the diameter of the rolling element 16, which will be described later, and the thickness D is smaller than the diameter of the rolling element 16.

A concave curved surface 20 is provided on each engaging portion 13a. In the illustrated embodiment, the concave curved surface 20 includes a circle 22 drawn on an imaginary plane centered on the axis 01 of the shaft 18 and perpendicular to the axis, and
A radius 2 extending from 1 to the center in the thickness direction of each engaging portion 13a
It is a concave conical surface formed to be point symmetrical with respect to the intersection point 02 with 4. This point of intersection is called the geometric center. The rolling element 16 is arranged so that its center coincides with the geometric center.

The inner part 12 includes three circumferentially arranged members 26.
It consists of 28.30. Preferably, these members are formed in the same shape. Each member has an engaging piece at each end in the circumferential direction, and the first engaging portion 13a is configured by being fixed to the engaging piece or the engaging piece of an adjacently arranged member. Ru.

In the embodiment shown in FIGS. 3-5, three members 26
．． 28.30 has the same shape and has an engaging piece 27a at one end in the circumferential direction and an engaging piece 27b at the other end, and both engaging pieces are integrally formed by an arcuate body 27c. It has become.

Each engagement piece passes through the geometric center 02 and the axis O of the shaft 18.
A first joint surface 32a that is perpendicular to I, and a second joint surface 32b3 and a third joint surface 32 that are perpendicular to the first joint surface 32a and parallel to a plane that includes the geometric center 02 and the axis 01, respectively.
It has c. If formed in this way, as shown in FIG. 3, when the two engaging pieces 27a and 27b are joined together, a step will be formed at the joined part, making it easier to position the adjacent members relative to each other.

In the embodiment shown in FIGS. 6 and 7, the three members 26, 28, 30 forming the inner part have the same shape. An engaging piece 29a at one end in the circumferential direction and an engaging piece 2 at the other end
9b is integrated with the body portion 29c. Each engagement piece has an abutment surface 33 that includes a geometric center 02 and an axis 01.

Adjacent members 26, 28, and 30 have rolling elements 16 interposed between the engaging piece of one member and the engaging piece of the adjacent member, as shown in FIG. A hexagon socket head cap bolt 38 can be attached by means of a pin 36 or as shown in FIG.
The rolling element 16 is held between both engaging pieces.

Adjacent members can be joined together at their outer peripheral surfaces by electron beam welding or laser welding.

The boss portion 13b is formed by the body of the member 26, 28, 30. An internal spline 40 is cut in a portion of the body excluding the connecting portion with the adjacent body, and on the other hand, the shaft 18 having a spline on the outer circumferential surface is fitted into the boss portion 13b, and the boss portion 1
3b with the retaining ring 42 (Fig. 2), and the inner part 12
is connected to shaft 18.

The outer part 14 surrounds the inner part 12 and has a recess 44 that receives each engaging part 13a of the inner part 12.
The second engaging portions 15a are provided at equal intervals of 120° in the circumferential direction.

Each engaging portion 15a of the outer component 14 has a shape that projects outward in the radial direction from the base portion 15b, and the engaging portion 15a and the base portion 1
One end in the axial direction with respect to 5b is sealed by a closing portion 15c, and the other end is open. A shaft 46 is integrally coupled to the closing portion 15c. The inner part 12 is inserted into the outer part 14 through the opening of the outer part 14.

The recess 44 has on both sides two planes 45 parallel to the plane containing the axis O8 of the shaft 18 and the geometric center 02 of the engagement part 13a of the inner part 12, these planes 45 being parallel to the axis O8 of the shaft 18. extending along.

The distance between the two palm surfaces 45 is 2R.

The rolling element 16 is a sphere of radius R in the illustrated embodiment.

This rolling element 16 rolls into contact with the concave curved surface 20 of each engaging portion 13a of the inner part 12, and is held in a fixed position by the concave curved surface 20. The rolling elements 16 are dimensioned to provide a loose fit against the concave curved surface 20 of the inner part 12 and against the two flat surfaces 45 of the outer part 14.

In the above embodiments, the concave curved surface is a concave circular male surface, but instead of this, the concave curved surface can be formed by a concave spherical surface, a concave elliptical surface, a concave composite surface, a concave polygonal surface, or the like.

The concave elliptical surface and the concave compound surface are not in full surface contact with the rolling element, but are in partial surface contact, and the concave polygonal surface is in point contact. A complete surface contact, such as the contact between a concave spherical surface and a sphere, has a lower surface pressure than a partial surface contact, a partial surface contact has a lower surface pressure than a line contact, and a line contact has a lower surface pressure than a point contact, but in processing, Complete surface contact is the most difficult, followed by partial surface contact, line contact, and point contact, which are the easiest. Therefore, depending on the magnitude of the rotational torque to be transmitted, it is decided whether to use complete surface contact, partial surface contact, line contact, or point contact, and select a concave curved surface. That's preferable.

In the above embodiment, the rolling element 16 is a sphere, but instead of being stiff, the equatorial part of the sphere is a circular contoured surface with a uniform diameter, and the remaining eight parts are spherical, or the first engagement The part held by the concave curved surface of the second engaging part and the part that contacts the flat surface of the second engaging part are spherical surfaces, and the part connecting the stiff spherical surfaces can be formed into an arbitrary shape.

Each engaging part 13a of the inner part 12 is inserted into the recess 44 of the engaging part 15a of the outer part 14, grease is sealed inside the outer part 14, the opening of the outer part 14 is covered with a boot, and the universal joint 10 is assembled. is considered to be in use. For example, the shaft 18 is connected to the drive side and the shaft 46 to the driven side.

The rotational torque transmitted from @1 is transmitted to the engaging part 13a of the inner part 12, the concave curved surface 20, the rolling element 16, and the engaging part 15a of the outer part 14 in this order, and is taken out to the shaft 46.

When the flexible fiber arm 10 is rotated with a joint angle,
The rolling element 16 moves axially in the recess 44 of the outer part 14, and at the same time a relative movement of the rolling element 16 and the outer part 14 in the radial direction occurs. Since these movements are performed by rolling of the rolling elements 16, the r9 friction resistance is small.

[Brief explanation of the drawing]

Fig. 1 is a sectional view taken along a plane perpendicular to the axis of the universal joint, Fig. 2 is a sectional view taken along line 2-2 in Fig. 1,
FIG. 3 is a plan view of the inner part, FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, and FIG. 5 is a sectional view taken along line 5-5 in FIG. 3. 6 is a sectional view similar to FIG. 4 of another embodiment of the inner part; FIG. 7 is a sectional view taken along line 7--7 of FIG. 6; and FIG. FIG. 4 is a cross-sectional view similar to FIG. 4; 10: Universal joint, 12: Inner part, 13a, 15a: Engagement part, 14: Outer part, 16: Rolling element, 18.46: Shaft, 20: Concave curved surface, 26.28.30: Member, 27a, 27b , 29a, 29b: engaging piece, 44: recess. Agent Patent Attorney Nobuyuki Matsunaga Figure 1 Figure 2 42 13b 42 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] An inner part provided with three first engaging parts arranged at equal intervals in the circumferential direction, extending in the radial direction, and having a concave curved surface, the three members being arranged in the circumferential direction. Each of these three members has an engaging piece at each end in the circumferential direction, and the engaging piece is fixed to the engaging piece of the adjacently arranged member to form the first engaging piece. The first part that constitutes the joint
an inner part that is integral with the shaft of the inner part; and a second engaging part, which is an outer part surrounding the inner part and has a recess formed by two planes for receiving each of the engaging parts, are arranged equally in the circumferential direction. held by a concave curved surface of a first engaging portion of an outer part integral with a second shaft and a first engaging part of the inner part, which are spaced apart;
and a rolling element disposed within each of the recesses so as to contact a plane of the second engagement portion of the outer part.