JPH033075B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a method of forming an internal gear having a trochoidal tooth profile or an external gear having a circular arc tooth profile by internally meshing the internal gear with a circular arc tooth profile. The present invention relates to a tooth-shaped contact surface of a trochoidal motor or pump that obtains a motor or pump action by utilizing changes in the volume of a space created by the trochoidal motor or pump, and more particularly to the surface shape of the contact surface.

(Prior Art) First, a known trochoidal hydraulic motor will be explained with reference to FIGS. 2 and 3.

The trochoidal hydraulic motor consists of three parts: an output mechanism part a', a displacement mechanism chamber part b', and a valve mechanism part c'. Rotational force is transmitted to the output mechanism part a' and the displacement mechanism chamber part b' by the drive 1. Rotational force is transmitted to the displacement mechanism chamber b' and the valve mechanism c' by a valve switching drive 2. For this purpose, the driver 1 and the valve switching drive 2 have spline portions at both ends thereof. Further, the output mechanism section a' mainly has an internal spline inside thereof, and removes the eccentric motion by removing the rotation of the external gear 3 accompanied by eccentric motion generated by the displacement mechanism chamber b' via the drive 1. It consists of an output shaft 4 that extracts only the rotation as rotational force, a housing 5 and a bearing 6 that supports the output shaft 4, and transmits the output to the other side and supports external loads, and the valve mechanism part c' is Mainly, it has an internal spline inside, and the rotation of the external gear 3 accompanied by the eccentric movement generated by the displacement machine chamber b' is removed by removing the eccentric movement and extracting only the rotation by passing it through the valve switching drive 2. Rotating valve 7
and a valve plate 9 that is fixed to the ring 8 and switches the flow path of pressure oil in cooperation with the valve 7.
and a valve plate 10, the pressure oil supplied from the pump is transferred to the volume change chamber 11 of the displacement mechanism chamber b'.
The oil on the return side is collected from the volume change chamber 11.

The displacement mechanism chamber b' is a part targeted by the present invention, and as shown in FIG. A trochoidal tooth profile is adopted as the tooth profile of the external gear 3 which internally meshes with the internal gear 12, and the number of teeth of the external gear 3 is one less than the number of teeth of the internal gear 12. Further, the internal gear center 14 and the external gear center 15 are eccentric, and the external gear 3 and the internal gear 12 are connected to each other due to their contact points.
The same number of volume change chambers 11 as the number of teeth (seven in the case of FIGS. 2 and 3) are formed. And the valve mechanism section
By sending the pressure oil to the volume change chamber 11 through c', the volume change chamber 11 changes its volume and repeats expansion and contraction, and the external gear 3 rotates around the internal gear center 14, and the pressure oil Converts pressure energy into rotational force. This rotational force is transmitted from the internal spline of the external gear 3 to the internal spline of the output shaft 4 via the drive 1', and only rotation without eccentric movement is extracted to the outside.

In the trochoidal hydraulic motor described above, the internal gear 12 and the external gear 3 are internally meshed with each other to transmit power and partition the individual volume change chambers 11. If only the function of power transmission is to be performed, it is sufficient that only a part of the tooth profile of each internal gear 12 and the tooth profile of the external gear 3 are internally meshed. 3 is modified so that only the concave portion of the tooth profile of the external gear 3 meshes with the tooth profile of the internal gear 12 to maintain strength;
Although it is possible to reduce wear, when used as a motor or pump, the volume change chamber 11
Since the function of partitioning is also required, the individual tooth profiles must always mesh.

(Problems to be Solved by the Invention) In order to downsize and increase the pressure of trochoidal hydraulic motors or pumps, external gears, which are meshing and sliding parts, have high-strength characteristics, and internal gears have high-strength characteristics. Must have hardness properties. For this reason, both external gears and internal gears are usually manufactured from metal materials with a relatively high coefficient of friction, which leads to a decrease in power conversion efficiency and an increase in the temperature of the fluid used. Ta.

Therefore, proposals have been made to line the tooth surface with a low-friction material or to apply a thin electroless nickel coating to lower the coefficient of friction, but these have not sufficiently solved the problem of wear.

On the other hand, it is also known to form a chemical conversion coating such as a phosphate coating on the sliding parts of hydraulic equipment to reduce the coefficient of friction of the sliding parts. This chemical conversion film itself does not have a low coefficient of friction, but it has a low coefficient of friction because it retains a large amount of lubricating oil in minute irregularities.

It is also possible to form the above-mentioned known chemical conversion coating on the meshing and sliding contact surfaces of the teeth of a trochoidal hydraulic motor or pump, but the chemical conversion coating itself has the disadvantage of being easily worn and peeling off in a short period of time. There is.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a tooth-shaped contact surface of a trochoidal hydraulic motor or pump that has a reduced coefficient of friction and reduces power loss.

(Means for Solving the Problems) The present invention is characterized in that a mesh-like unevenness is formed on the contact surface of the tooth profile of a trochoidal hydraulic motor or a pump, and a chemical coating with a film thickness lower than the height of the unevenness is formed. The purpose is to apply a treated coating to the contact surface.

(Example) An example of the present invention will be described below with reference to FIG.

In general, the meshing and sliding contact surfaces of the teeth of a trochoidal hydraulic motor or pump mechanism must be made of high-hardness material and machined with high precision, so they are ground. Taking the external gear of the trochoidal hydraulic motor as an example, the external teeth that are the contact surface of the external gear 5 are ground in the axial direction, so as shown in A of FIG. Grinding marks remain in the axial direction (tooth trace direction), and unevenness consisting of peaks indicated by A and valleys indicated by B in the figure remains in the circumferential direction (direction perpendicular to the tooth trace direction). The cross section of the pump crest A in the direction of the tooth trace is smooth as shown in the figure.

Now, if we apply a phosphate film C to the external teeth shown in A and B in the figure and make them mesh and slide as shown in C and D in the figure, it will take a short period of time as shown in E and F in the figure. The coating C on the grinding grooves A of the external gear is completely worn and peeled off. The parts without this film cannot hold lubricating oil that also serves as hydraulic oil, which increases the frictional resistance of the transmission mechanism.

In the present invention, as shown in FIGS. 7 and 6, peaks A and valleys B (unevenness) are provided in the axial direction and circumferential direction of the external teeth.
The formation of the peaks A and valleys B is performed by grinding. This is then subjected to barrel processing and shot peening to round off the tips of the ridges A, and then a phosphate coating C is applied. In this case, the thickness of the coating C is made smaller than the height of the peaks A and valleys B. Here, the height of the peaks A and valleys B is preferably 1 to 10 microns, and the thickness of the film C is preferably about 3 microns, which is slightly lower than the height of the peaks A and valleys B. .

According to the external teeth of the present invention, the wear state after sliding and meshing remains in the form of a mesh in the axial direction and circumferential direction of the external teeth, as shown in R and N in the figure, and the wear state remains at any position on the contact surface. It will hold enough lubricating oil that also serves as hydraulic oil.

The above description is an example of the present invention, and the present invention is not limited to the external gear of the trochoidal hydraulic motor, but also applies to the tooth profile of an internal gear, the roller tooth profile, and the external gear of a trochoidal pump. It also includes internal gears, which utilize trochoidal curves for sliding that involves volume changes, forming mesh-like unevenness that intersects at a predetermined angle on the meshing contact surface, and that has a chemical formation lower than the height of the mesh-like unevenness. It is sufficient to apply a treated film. In this case, since the tooth profile is usually ground, it is convenient to use the grinding marks as they are for the unevenness.

Further, the present invention includes various chemical conversion coatings in addition to the phosphate coating.

(Effects of the Invention) The effects of the present invention configured as described above are as follows.

Lubricating oil that also serves as hydraulic oil is retained at any position on the sliding and meshing contact surfaces, reducing wear and friction loss as a transmission mechanism.

The control mechanism frequently operates intermittently, which is disadvantageous to the formation of a lubricating oil film, but the present invention has the advantage of retaining a small amount of lubricating oil and retaining lubricating oil at any position. When used in a control mechanism, control accuracy is improved, and as a transmission mechanism, it can reduce noise, improve transmission efficiency, and increase durability.

The starting characteristics of the motor or pump are improved.

[Brief explanation of the drawing]

1 to 1 are cross-sectional views of contact surfaces for explaining the present invention, FIG. 2 is a cross-sectional view showing an example of a known trochoid type hydraulic motor, and FIG. 3 is a cross-sectional view taken along line AA in FIG. It is a diagram. A: Mountain, B: Valley, C: Film.

Claims (1)

[Scope of Claims] 1. A trochoidal gear in which the internal gear has an arcuate tooth profile and the external gear has a trochoidal tooth profile or an arcuate tooth profile, and the volume change between both tooth profiles is used to obtain a motor or pump action. In a motor or a pump, a contact surface is formed with an uneven surface in the direction of the tooth trace of the grinding marks of a tooth profile and in a direction crossing the tooth trace direction of the grinding marks, and the contact surface is coated with a film thickness lower than the height of the irregularities. A tooth-shaped contact surface in a trochoidal motor or pump, characterized by comprising a chemical conversion coating formed thereon. 2. The tooth-shaped contact surface of a trochoidal motor or pump according to claim 1, characterized in that the height of the uneven surface is 1 to 10 microns.